This page contains no text.
The Baldwm Librarym LTmir rlrnm rL s
ti/A-? 9'- /67Ir 0.0:
HOME TEACHINGS IN SCIENCE.
AV-jW-w--- -Ii` ~
HOME TEACHINGSIN SCIENCE.By PROFESSOR COWPERAND OTHERS.2Sit) IHlIustrations. /-cOLONDON:FREDERICK WARNE AND Co.BEDFORD STREET, COVENT GARDEN.NEW YORK: SCRIBNER, WELFORD,' AND CO.
CONTENTS.PugeJOHN RAYNER 7THE FIRST RAILWAY TRAIN 17THE THERMOMETER 36THE WINDMILL. 48THE BROKEN PUMP 65NOTHING WASTED 76THE BAROMETER 83THE LOCK 95THE SECONDS CLOCK 103THE EIGHT-DAY CLOCK .120THE ELECTRIC TELEGAPI 129MAKING TELEGRAPHS 117APPARENT COURSE OF THE SUN 159
HOME TEACHINGS IN SCIENCE.JOHN RAYNER;OR,$cintific Unob3tefge useb for tbe .r1iu111-ioi11 of ULifC."PAPA," said Richard Bourne one evening, closing"Pepper's Cyclopedic Science," "have you ever knowna boy who was able to make his knowledge of science ofgreat use to other people ?"" Yes," replied his father, " I have known one very re-markable instance of a lad using his scientific knowledgefor the benefit of his fellow.creatures."" Oh, do tell me about it," said Richard, eagerly." During the summer holidays, when I was quite a boy,I had a young friend (a schoolfellow) staying with meand my younger brother Edward. His name was JohnRayner, and he was then fourteen, two years older thanmyself. I was much attached to him, not only from his
8 JOHN RA YNER.being good-natured and obliging, but because, with thesame love of reading as myself, he was far more cheerfuland lively, and always seemed to be able to tell us every-thing at the very moment that it was wanted. Whetherin our games, or in our school studies, he was generallyappealed to by the boys. How he obtained so muchinformation, I do not remember that we ever troubledourselves to inquire; but my father, who liked Johnexceedingly, said it was from his constant habit of obser-vation. Certainly, many things were observed and re-membered by John, which other boys had not taken theleast notice of, though enjoying the very same oppor-tunities. Well, during the midsummer holidays that Iwas speaking of, my mother and father were unexpectedlyobliged to leave home, to see a sick relation who lived atsome distance. The evening before their return, we threeboys occupied ourselves in assisting our old gardener toput the garden in order. The garden sloped down to abroad river, which joined the sea at a few miles' distance.While the gardener was arranging some flower-pots ona stand on the grass-plot, and John and Edward werewatering the flower-beds, I was sweeping the turf near thewater's side. Suddenly I observed, at a little distance,something that I could not well make out, floating downthe river. I called to the gardener, to ask him what hethought it could be."' Oh, it is nothing but a dead pig,' answered the gar-dener, as he sauntered towards me."' Are you sure of that ? I exclaimed, for I thought,as it drew nearer, that it looked like a child."' I do not think it is a pig,' said John Rayner, whohad joined us. 'I am sure it is not: it is a boy!' And
JOHN RA YNER. 9in a moment, to our great surprise, he flung off his jacket,and threw himself into the river.""Oh, papa!" exclaimed Richard, "what did you andyour brother Edward do ? ""Neither of us knew what we were about," repliedMr. Bourne. "Edward exclaimed in terror, He will bedrowned! he will be drowned he will be drowned!' andplaced his hand before his eyes. I would have dashedafter the brave fellow, but the gardener, who knew Icould not swim, held me back. He called out to Johnnot to fear, but to keep well up against the tide; this lastadvice was very necessary, for the current was strong,and John found himself drifting in the direction of themouth of the river. Fortunately, he was a good swimmer,and his courage never left him. He swam with all hisstrength towards the floating body, and seizing it by thehair with one hand, with the other he directed his courseback to the shore. The gardener, Edward, and I watchedhim anxiously, and the moment he came within reach,assisted him to land, and in laying the body on the grass-plot.""Was the body quite lifeless, papa ?" said Richard,eagerly."We all thought so at the time; all, at least, exceptJohn. My brother Edward recognized the poor littlefellow at once, as the son of a washerwoman that livedon the common. He had seen him playing at marblesbut the day before, and he therefore felt more shockedthan any of us. He burst into tears as he exclaimed,'Poor, poor woman, she will never see her boy again!'" I remember how much we were astonished when Johnreplied in a hurried tone, 'She may see him again, if we
io JOHN RA YVNR.use the right means to recover him. Let us lose notime. Edward, run quickly for a doctor, while we carryhim into the house; and as you pass the kitchen, tellSusan to get a bed warmed directly.' You may be surewe lost no time in obeying him."' We had better hold the poor boy up by the heels,'said the gardener, 'to let the water that he has swallowedrun out.'"'No, no, no!' exclaimed John; 'by doing so, youwill kill him, if he is not already dead. We must handlehim as gently as possible. Run for the shutter of thetool-house, and we will place him upon it.' When wehad done so, and the body had been carried into the house,Susan and the gardener urged John to place it near thekitchen fire, saying that, as the body was as cold as apiece of marble, there could be no better plan than toplace it as near to the fire as possible. After a littlepersuasion, however, they yielded to John's entreaty, andthe body was carefully rubbed dry, and placed on a mat-tress on its right side, between hot blankets. I shouldtell you that, while I was fetching the shutter, John hadwiped the body gently with a handkerchief to remove asmuch of the water as he could at the time."There were no wet clothes to be removed, for theboy had evidently been bathing, and had most probablygot out of his depth while amusing himself in the water.After the body had been laid in bed, John bound the headwith flannel, and placed it high on the pillows. He thenbegged Susan to rub the body all over with hot flannels,which the gardener heated from time to time. I was toldto fill four common bottles with hot water. These bottles,wrapped in flannel, were placed under the armpits and
70HNV RA YAER. IIat the feet. John then tried the effect of snuff andhartshorn, to create sneezing, and threw cold water intothe boy's face ; but all without effect. He next took thekitchen bellows, and having carefully blown out all thedust that had collected within them, directed me to closethe mouth and one nostril, while he gently blew into theother nostril from the mouth of the bellows. When hesaw the chest appear to rise as if filled with air, he putaside the bellows, and pressed the stomach upwards toforce the air out. He repeated this process fifteen ortwenty times in a minute, to imitate natural breathing."In the midst of his exertions, many of the poorerneighbours assembled, and made their way into the room,They expressed great sorrow for the sudden death of thechild, and warm sympathy for the unfortunate parent.Not one of them, however, could offer us the least as-sistance, because they were quite ignorant that any meanscould restore a person apparently drowned. They watchedus with curiosity and displeasure, and began to mutteramong themselves that they should not like a son oftheirs to be so treated, dead or alive. At last one womandeclared 'that all that nonsense would never bring thedead back to life.'"" And did you turn the people out of the room, papa?"said Richard. "I am sure I would have done so.""We did not think much about them at first," repliedMr. Bourne; " we were too much engaged in our occu-pation. But when John found that they crowded nearthe bed, and impeded the fresh air, which is absolutelynecessary to assist the recovery of a drowned person, heinsisted upon their leaving the room, and as he spokefirmly, although gen y, they gave way. All this time
I2 7OHN RA YNER.the windows and doors were left wide open. At lastEdward arrived, but the doctor was not with him. Hewas absent from home when Edward called, and a mes-senger was sent for him. Edward was anxious to be ofservice, but he could do little else than heat the flannels,or fill fresh bottles with hot water. We could not induceJohn to allow any of us to inflate the lungs. An hourand a half had now passed since the boy had been takenfrom the water, and still no signs of life appeared. Thegardener and Susan would have given up all furtherexertions as useless, and they urged John to think of hisown health, assuring him that from standing so long inhis wet clothes, he would certainly be ill, while he couldno longer do any good. John, however, resolutely de-clared that he would not cease his attempts to restore theboy to life till the doctor should pronounce them to beuseless; but to protect himself from the chill of his wetclothes, he asked Edward to fetch some wine or brandyand water, and to hold the glass for him while he drankit, as he could not disengage his hands. I need not saythat Edward obeyed his directions. The time seemed verylong, particularly to Edward, who was not employed somuch as the rest of us. He kept on the watch for John'sorders, gazing alternately on the pale face of the ap-parently dead boy, and then straining his eyes from theopen window, to catch the first sight of the doctor.Another half-hour passed, and at the end of that time,to the inexpressible delight of us all, the boy opened hiseyes, and uttered a faint sigh.""Oh my dear papa," said Richard," what did John say ? "" He made no exclamation whatever, but he claspedhis hands with exceeding joy. As for the rest of us, the
"O7HN RA YNER. 13surprise was so great, that I am ashamed to say we werequite bewildered: we ran backwards and forwards, en-treating John to tell us what we were to do next. In alow voice he told us that the greatest stillness was neces-sary, but that a teaspoonful of warm water might begiven him. This the boy swallowed, and seeing that hewas able to do so, John told us that now we might givea small quantity of brandy and water. After a few spoon-fuls had been poured down the boy's throat, he openedhis eyes again, and seemed to smile on his preserver.""But, papa," said Richard, " where did John Raynerlearn the proper means to recover a drowned person ? ""He was very fond of practical science, and had onceread a book which explained, on scientific principles, howan apparently dead person might be restored to life. Soonafterwards he met with the' Rules of the Humane Societyfor restoring persons apparently drowned.' He comparedthem with what he had read about cases of suspendedanimation, and thus, no doubt, impressed them on hismemory. Knowing the reasons for everything the rulesenjoined, he was not likely to make any fatal mistake,which he might possibly have done if he had only remem-bered them. But to return to our story:"After William had swallowed the brandy and water,and had taken a little thin gruel, he became able to speaka few words; but John begged him not to exert himself.At length the doctor arrived, but not to see a lifelessbody. The patient was breathing softly and freely, andthere could be but little doubt of his recovery. Whenthe doctor heard all that had been done by John, who,he saw, was a mere lad, he grasped his hand with eager-ness, and tears fell from his eyes as he expressed, in a low
II 7OHNV RA YNER.but energetic tone, the sincere admiration which he feltfor John's conduct. To the doctor's observations on hisown flushed cheek and feverish pulse, John could hardlyanswer. While he was exerting himself, he felt no illness,and indeed he had not thought of himself. But now thathe heard that William was out of all danger, and sawhim breathing freely, his own knees began to tremble, hishead became dizzy, and he felt exceedingly ill."'My dear fellow,' said the doctor, 'you must go tobed. If you forget yourself, we must take care of you.'"'Will he need me?' said John, motioning towardsWilliam."'Not in the least,' answered the doctor; 'I will giveall necessary directions, and I am sure your friend andthese good people will take care to follow them. Littlemore is requisite than rest, together with slight nourish-ments at intervals.'" John said no more, but allowed us to assist him tobed. The next morning, at his own earnest desire, weremoved William to his mother's cottage, and there hesoon became as well as ever again. John Rayner'srecovery was by no means so rapid. On the return ofmy parents the next day, they found him seriously ill. Icannot describe to you my anxiety during the first weekof his illness. I loved my friend far more than ever.While he remained in this state, I could not absent my-self from him. No other pursuit seemed to enter myhead, except that of nursing and attending on him. Mymother nursed him exactly as if he had been her ownson, and the doctor seemed never weary of his attentions.At last, to our great joy, the fever abated, and all dan-gerous symptoms ceased. I shall never forget the meeting
JOHN RA YNER. 15between him and William Jackson. The little gratefulboy had daily applied for the doctor's permission to seehis preserver, and when he stood for the first time by hisside, he could not speak-he could only shed tears, andkiss John's pale thin hands. Mrs. Jackson's warm ex-pressions would have overcome John, who when in healthwas easily touched by kindness; but my mother requestedher to remember that even pleasure might bring back thefever. 'Then what must I do if I may not tell him whatI feel ? said the grateful woman; 'I have nothing to givehim. Oh! I never wished for riches so much as I donow, that I might reward him as he deserves.'"'But I do not want to be rewarded, Mrs. Jackson,' Iremember John answered; 'all the riches in the worldcould not make me so happy as I am at this moment;they could not give me the dear kind friends that arenow around me, nor your boy's happy smile. No, mygood Mrs. Jackson, you need not wish to be rich for me.'" William entreated my mother so earnestly to beallowed to assist in nursing John, that she consented thathe should spend the hours between school at our house;and from that day, until John was well enough to be re-moved to his friends, who lived at a considerable distance,William assisted us in waiting on him. John recoveredhis health sufficiently to join me at school-a few weeksafter the holidays were over, and we became still moreattached to one another. His habits of observation in-creased as he grew older, and he has had many oppor-tunities of employing them to the benefit both of othersand himself. Before he was two-and-twenty, he wasengaged to explore parts of India, to make surveys ofthe country, and drawings and descriptions of its natural
16 OHN RA YNER.history. Since that time he has twice visited England,and I hope he will soon return to reside here. Then myboy will know my excellent friend, and I have no doubtwill love him also.""Oh, I am sure I shall," replied Richard, earnestly;"and I shall like to hear all his adventures. What afine fellow he must be!'" He is, indeed. I hope you will profit by his example.""I will try," said Richard, modestly. "Thank you,papa, for telling me the story. I see by it that all kindsof knowledge are useful even for boys; so I shall try tounderstand and remember all I read; then, some day Imay be as useful as he was."f
THE FIRST RAILWAY TRAIN.*ONE morning two loud raps at Mr. Harmer's doorannounced that the postman had brought a letter. Theservant put it into Mr. Harmer's hand, and said thepostage was thirteen-pence. Mr. Harmer paid the money,but soon observed that the name was "Mr. FrederickHarmer, junior." " Fred," said he, "here is a letter foryou, therefore you must pay the thirteen-pence.""Thirteen-pence! " exclaimed Fred, "what a deal ofmoney to pay for a letter from a school-fellow! "" Well," said his father, "if you do not like to pay thepostage, let me keep the letter, and you keep your money.""Where does it come from ?" said Fred; "it musthave travelled a long way to cost so much.""It has come from Manchester," said his father, " onehundred and eighty-six miles from London, for which theycharge eleven-pence, and two-pence more is charged forbringing it from London to our house."" Manchester-Manchester," said Fred, trying to recol-lect; " I have no school-fellow who lives at Manchester."* This paper and the other scientific articles in which the sameboys are introduced were written by the late Professor Cowper,very many years ago, before the introduction of the penny postage,and when, in the present sense of the term, there was only onerailway in the country; but nothing has occurred in the progressof science, to cast doubt on the correctness of Mr. Cowper's factsand clear explanations.2
18 THE FIRST RAIL WA Y TRAIN.Oh! perhaps it is from Uncle Alfred! there is the thirteen-pence, papa." And then Fred broke the seal in an instant,saw his uncle's name at the bottom of the page, and readwith glistening eyes the following letter:"DEAR FRED," As business will detain me some time in Man-chester and Liverpool, I shall feel much pleasure if yourfather will allow you to spend a few weeks with me; Ican then show you some of the manufactories, and wewill take a trip in the coach drawn by a steam-engine onthe railway. My friend Mr. Lincoln will take care ofyou on the journey down, and I will take you back."Write me an answer by return of post: you must alsowrite to my friend Mr. Lincoln, and tell him you willmeet him at the coach-office."Your affectionate Uncle,"ALFED HARMEE1.""Dear papa, how very kind of uncle Alfred! May Iwrite that you will permit me to go ?" His father gavehis consent on condition that Fred would write down ina memorandum-book an account of the different thingsthat interested him during his excursion, and his ownthoughts on all that he saw and heard; and Fred, quitedelighted, prepared to write the letter."Oh!" said he, "how glad I am I can have such aletter for thirteen-pence; it seems such a little moneynow, for bringing a letter one hundred and eighty-sixmiles in one day."His father told him that the mail coach to Manchesteremployed more than one hundred and eighty horses.
THE FIRST RAIL TA Y TRAIN. 19Fred set off at the appointed time, and the weatherbeing fine, he rode outside the coach. Mr. Lincoln hadsome business at Derby; their journey, therefore, ledthem through St. Albans, Dunstable, Northampton,Leicester, Derby, Cromford, Matlock, Bakewell, Chapel-en-le-Frith; and in due time he arrived at Manchester,where his uncle received him very kindly.Fred's Letter to his Father."DEAR PAPA, Manchester." How glad I am that you allowed me to acceptUncle Alfred's invitation I have only been four daysfrom home, and I am sure my sheet of paper will not behalf large enough to tell you all I have seen. Our journeyfrom Derby, where we slept, to this place, was so beau-tiful, that I wished for you, and mamma, and George, ahundred times, to enjoy it with me. Mr. Lincoln toldme he generally travelled that road to Manchester onaccount of its great beauty. I never saw real rocksbefore, although I have often read about them. Onecalled the High Tor, at Matlock, is a noble rock, threeor four hundred feet high, and there is a river runningat the foot of it. The rock seems just as if it had beenbroken from top to bottom. In some places you seelong slanting lines, as if one part of the rock had sunkdown. But I cannot write anything more of our journey,because I wish to tell you about the steam-carriages andthe railroad." Yesterday Uncle Alfred took me to the railroad, andhe showed me all the carriages and the steam-engine;and we s.w a Train (as they call six or seven carriages22.
20 THE FIRST RAIL WA Y TRAIN.-I ,' c; T fastened together)I " I r' I set off. They startedi' 1- very slowly, and pre-'. '' sently went along- i faster than our coachSdid when the horsesI,_ |-, ..! galloped. We saw a' 1: II train come in, andc V -- i te ti sa aSi! I they stopped them soSi, gently, that I wasS ) ,I quite astonished; and,-' '' there was not oneS'. i passenger that lookedI'i -i frightened; they allI Z seemed pleased thatThey had travelled sofast; then the steam-"Zengine was unfast-I ened from the train,S.' and the enginemanS'- '' i moved it about oneSJ j hundred yards, till itSame just under aS ,'.. water. As soon as theS'' engine came back,S '. and was hooked to- the train again, myS '' uncle and I got intoi i one of the open car-1 riages; he fixed upon. an open one in order
THE FIRST RAILWAY TRAIN. 21that we might see everything as well as possible. It wasnot long before the steam-engine began to pull very gentlyall the six carriages with one hundred and twenty peoplein them; and then we went faster, faster, faster, oh, sofast! I wish, dear papa, you had been with us,-thehorses galloping with the coach seem like nothing to it."What a wonderful invention the steam-engine is, andwhat a clever thought, to make an iron road for thewheels to run on; but how much time and labour itmust all have cost! At one place they have made theroad over a great black swampy place five miles long, byputting down many thousand loads of gravel. At anotherplace they have built a great high bridge, called theSankey Viaduct, over the Sankey River; and canal barges,with high masts and sails, go under it. At another placethey have cut through a hill called Olive Mount; thishill is all stone, but not a hard grey stone like the HighTor at Matlock, but reddish, and looks something likethat which grindstones are made of. All the rock thatthey cleared out they threw into a valley, and there madea great sloping embankment, at the top of which therailroad runs. We were only one hour and a quartergoing thirty-two miles! There is a mail coach at theend of the train of carriages, which carries the lettersbetween Manchester and Liverpool." Uncle Alfred has been very kind; he has explainedto me the steam-engine, and I have written down in mybook all I remember; and I think I can explain it evenso that George may understand it. Uncle Alfred is notoffended if I do not understand him immediately, andtherefore I do not mind asking him questions. I nevercan understand the explanation of a person who looks as
23 THE FIRST RAILWAY Y TRAIN.though he thought that I was stupid all the time I amspeaking."I wish I could draw like Uncle Alfred. When hesketches a machine for me, he makes me understand itquite clearly; so that I do not feel afraid that I shallnot understand a thing even if it does seem difficult atfirst. I could not help laughing when Uncle Alfred saida steam-engine was something like a squirt; but it isindeed, papa, as I will show you when I come home, forI have got it down in my book."Your affectionate Son,FRED."Fred stayed six weeks with his uncle, and during hisvisit, saw many of the manufactories. He went over acotton mill, a weaving factory, a calico printer's, an en-gineer's factory, a coal-pit, an iron foundry, the docksat Liverpool, and the Menai Bridge at Bangor. Hewrote several letters to his father; but the more he putdown in his book, the less time he had for long letters.This was his last to his father:"DEAR PAPA," My visit to Manchester is now nearly at an end,and I do not know whether to be glad or sorry. I am alittle sorry to lose seeing any more of the wonders ofmachinery, but I feel very, very glad, I shall have somuch to tell you all. I now see the great use of puttingthings down in a book, although at first I thought itwould be something like a task; I am sure I could nothave remembered a quarter of what I have seen, and nowI have only to look in my book, and it tells it me all
THE FIRST RAIL WA Y TRAIN. 23over again. We are to return to London this day week,and Uncle Alfred intends to spend a few days with you.He was intending to take me to see a printing machine,but he said you could take me to see the printing machinein London, and that he should like to go with us; so mypleasure is not at an end yet."Your affectionate Son," FEED."Uncle Alfred having concluded his business at Man-chester and Liverpool, he and Fred returned to London.They set off in a coach called the Telegraph, at five inthe morning. The first part of the journey Fred foundhimself very cold, having left his warm bed so early; yethe felt very cheerful at the thought of going one hundredand eighty-six miles in one day, and at the end of thatday seeing his dear parents."Uncle," said Fred, "I do not think I should like toget up every morning before five. Do those boys andgirls we saw going into the factory just when we set off,go there every morning at five o'clock ? "" No; they are probably only going for a few mornings,to make up time lost in repairing the steam-engine.Some years ago, however, children younger than youoccasionally worked in a factory from five in the morninguntil eleven at night, and for many weeks together.""What!" exclaimed Fred, "as long as we are travel-ling from Manchester to London! Oh, how tired theymust have been.""Yes," said his uncle; "many poor children were solittle cared for by their masters and parents that manyof them became cripples for life. A law has therefore
24 THE FIRST RAILWA Y TRAIN.been passed, to prevent, if possible, the children frombeing overworked. Do not think, Fred, however, thatall masters of factories are inhuman. There are goodmen and bad men in every class. Mr. Lincoln pointedout to you, I think, the large cotton mills at Derby, be-longing to Messrs. Strutt.""Yes," said Fred; "and the mills looked so whiteand clean, that I quite longed to go over them.""Well, great attention is paid to the comfort of thework-people in those mills. Messrs. Strutt have builta large school-room for the children. They take carethat the children shall learn something else beside spin-ning.""It seems quite silly, I think, uncle," said Fred, "formasters and work-people not to try to make each othercomfortable; for the master cannot get money withoutthe help of the workman, and the workman cannot earnwages unless he finds somebody to employ him. Theyought to do their best to please one another."The sun now shone out warm and bright, and Fredenjoyed the view of the country, the rapid motion of theTelegraph coach, and the expedition with which the horseswere changed. In short, Fred had become quite a traveller.As they met the various coaches coming along fromLondon, the Dart, the Tally-ho, the Courier, and others,the passengers began talking about the names of coaches,and as they gave their different opinions, Uncle Alfredasked Fred which name he liked best."I like the name of this coach best," said Fred: "theCourier is a good name for a coach, because a couriercarries news and goes quickly, but the telegraph carriesnews-most quickly of all."
THE FIRST RAILWVA Y TRAIN. 25The long rows of brilliant gas-lights at length appearedin sight, and in another half-hour the stage coach stoppedat Mr. Harmer's door. The parlour blinds were quicklydrawn aside, and the street door as quickly opened, whilehalf a dozen voices welcomed " Fred and Uncle." Onekind hand seized a cloak, another a hat, while a thirddrew the travellers towards the cheerful fire-side. In afew minutes Fred and his uncle were seated in the midstof a circle of affectionate and inquisitive friends, who wereall eager for answers to their several questions.The next day Mr. and Mrs. Harmer and George weredesirous to see Fred's memorandum-book. The drawingshad been made by his uncle, but Fred had written thevarious accounts in his own way." I hope you will begin from the very beginning," saidGeorge: "I should like to hear about your journey toManchester; for in your first letter you did not tell usmuch about it.""Well," said Fred, "I will do my best to please you:here is my little book, which I kept in my pocket duringthe journey, and while staying at Manchester. I thinkI had better read it myself, mamma, because the pencil-marks are unluckily often rubbed, and I suppose I shallmake out the meaning best." Fred accordingly beganreading the following extracts from his memorandum-book." September the 6th, I set off with Mr. Lincoln in anew coach from the Belle Sauvage, to spend some timewith my uncle at Manchester. The coach was made agreat deal lower than most of the other coaches that Ihave seen; and Mr. Lincoln said it was not so liable toupset, and therefore it might go very quickly with safety.
26 THE FIRST RAILWAY TRAIN.Everything about travelling seems to be done quickly.The coachman gets on the box quickly; they change thefour horses very quickly; and if a passenger walks slowlyup to the coach, the coachman says, 'Now, sir, if youplease,' to make him walk quickly. I did not suppose afew minutes could be of such consequence, until Mr.Lincoln told me, they changed horses twenty times be-tween London and Manchester, and then asked me, 'ifthey waste three minutes at each change, how much willthat be at the end of the journey ?' It would be a wholehour. Travelling must make people think a good deal ofsaving time."I heard the coachman, when we stopped at an inn,tell man to give the near wheeler a little water. I askedMr. Lincoln why they called the horse that was farthestoff from the coachman the near horse, and he told methat the horse on the left is the nearest to a postillion,because he rides upon it, and the horse on the right isthe farthest off from the postillion." I think it is very amusing to hear the different peopletalking outside the coach. One of our companions hadsailed with Captain Parry, and he told us many entertain-ing anecdotes of the Esquimaux. A gentleman who satnext to Mr. Lincoln was a Frenchman, who could notspeak a word of English. He was quite delighted whenMr. Lincoln repeated to him in French the traveller'samusing accounts. How much more obliging some peopleare than others in travelling Some take as much roomas they can, and speak rough and short; others, like Mr.Lincoln, seem to wish everybody to be as comfortable asthey are themselves." At one part of our journey, the horses became rather
THE FIRST RAILWVA Y TRAIN. 27restive. One of them had pranced about and frightenedthe others, and then they all galloped so fast that I be-came frightened. The French gentleman, who was notused to quick travelling in his own country, was quite asfrightened as I was, and wished to jump off the coach,but the coachman assured him there was no danger; andMr. Lincoln told him, whenever the horses ran away, itwas always safer to hold fast on the coach; and that ifhe jumped off, he would certainly be thrown violentlyagainst the ground, and be hurt very much. An Irishgentleman sat by my side, who had amused us much bythe funny stories he narrated; but when the horses begangalloping so furiously, he looked quite as much frightenedas the Frenchman. Suddenly he said to me,' I'11 troubleye, young gentleman, for a piece of chalk!'"' Oh, sir,' I exclaimed, 'I cannot think of chalk now,when we may all be over in a minute. What can youwant chalk for ?'"' Just exactly for that very reason, my honey,' heanswered; 'for I want to mark my own legs, that I mayknow them again, when we are all upset and kilt entirely !'"This answer set us all off laughing together, and bythe time we had done laughing the coachman had gotthe horses into a trot instead of a gallop, of which I wasvery glad." When we were crossing a little river called the Trent,the coachman told us, that one side of the river wasLeicestershire, and the other side Derbyshire; and Mr.Lincoln, who has travelled in foreign countries, said, thatsometimes a small stream would divide two great king-doms. When he travelled from France into Italy, hewent over a bridge, and one-half of the bridge was France,
28 THE FIRST RAIL WA Y TRAIN.and the other half Italy. In time of war, how disagree-able it must be, and how foolish it seems, for people wholive on each side of a little river, to fight with one another." We slept at Derby, and the next day went to see thebeautiful hospital, called the Infirmary. It looks like agentleman's house in the midst of a park: the trees, thegravel walks, and the flowers are all kept in the highestorder. When the sick people are getting better, howmuch they must enjoy such pleasant grounds! Theinside of the infirmary is so clean that you would scarcelythink anybody was ill there. We went all over it. Inthe cellar we saw a large stove, and a little brick roomall round it, full of holes to let the air go through againstthe stove, and so get warmed. From the top of this littlebrick room, there were brick flues, about as big as acommon chimney, that went to every part of the in-firmary, to convey the warm air to the rooms and passages."In the laundry, there was actually a little steam-engine! Who would have thought that sick peoplecould be made more comfortable by a steam-engine ? andyet they are, for it works a washing-machine, a mangle,and a pump. There is a large closet, that is warmed byhot air, into which they slide the clothes-horse when theyhave been washing; and so the sick people always haveplenty of clean linen. I asked who it was that had con-trived so many things for them; and Mr. Lincoln said, itwas Mr. Strutt, one of the proprietors of the great cottonmills, near Derby. When we left Derby, we passedMessrs. Strutt's mills, but Mr. Lincoln could not sparethe time to take me over them. At Cromford, we passedSir Richard Arkwright's mills, and Mr. Lincoln told mehe was the first person who spun cotton by machinery.
THE FIRSI T RAILWAY Y TRAIN. 29"We arrived at Manchester at night, and Uncle Alfredmet me at the coach-office. The next day he took meto several parts of Manchester. What a busy place it is !In almost every manufactory we passed there was a steam-engine, which made me wish to know something aboutsteam-engines; they seem so very useful; and UncleAlfred, when we got home in the evening, made me thedrawings in my book, and explained them to me." There are two kinds of steam-engine: one is calledthe Condensing EJngine, because the steam is somehowcondensed in it by means of cold water; and the other iscalled the High Pressure Engine, because the steam presseswith very high power in it. Uncle Alfred says the HighPressure engine is easiest to understand, and he beganto explain it to me, by telling me it was something like asquirt. Directly he said so, I began to hope that I shouldunderstand it, for every boy knows what a squirt is. Ihave often mended the plug, or piston, as they call it inthe steam-engine, by putting some tow round it. Theround part of the squirt theycall the cylinder, and thehandlepart theycall thepiston-rod. I find I must learn the __,.. Pislou-rod.names of things when they are --_!different from those I have Cylinder.been used to, or else I can- Inot tell what people are talk- i Piston.ing about."Well, now, suppose thepiston of the squirt made toslip up and down very easily,and the hole at the bottom of the squirt made large with
30 THE FIRST RAILWAY Y TRAIN.a gimlet, and then the point of the squirt put througha hole in a cork, and the cork put into atin bottle with some water in it; if youwarm this over the fire, the steam willpush the piston up to the top. We must,S however, take it off the fire directly thepiston reaches the top, or else it would7T2IT burst, because the steam cannot get out.i If we could only let the steam off thatj had pushed the piston up, and then letsome steam into the upper part of thecylinder above the piston, we could push the piston down0I-IS -. FiTe p pi.e.i' ba.II p,File b.is. a y / [nj 7 [3V
THE FIRST RAILWAY TRAIN. 31again; and then the squirt and the bottle would be alittle steam-engine."In a steam-engine, the piston-rod slides through ahole at the top of the cylinder at (A), in which some towis put to make it fit close enough to prevent the steamgetting by. There is a pipe (T), which I shall call thetop pipe, and a pipe (B), the bottom pipe, and a pipe (i),through which the steam goes into the cylinder, and apipe (o) (which passes on one side of r), through whichthe steam goes out of the cylinder; and these four pipes,0SI 1 [ FIG. 2.are all joined together in the shape of a cross. In themiddle of the cross at (c) there is a cock. This cock iscalled the four-way cock, because itopens and shuts all the four pipes.I thought this would be very diffi-cult to understand, but my uncle'sdrawings have explained it perfectly lito me."This is the shape of the plug of Plug.the cock; that is, the part which otch.turns. It has two deep notchesfiled in it opposite to one another,
32 THE FIRST RAIL WA Y TRAIN.leaving a solid division in the middle, and a section of itwould look like this:-Notch. Li. n.ui..Division. .Notch. _..Now, when the division stands thus \ like (Fig. 1.) thesteam goes to the top of the cylinder, and pushes thepiston down; and when the division stands thus / as in(Fig. 2.) then the steam goes to the bottom of the cylinderand pushes the piston up. While the fresh steam isgoing through the right-hand notch of the cock into thecylinder, the steam that has been used is going throughthe left-hand notch out of the cylinder into the open air.The steam-engine itself turns the cock by a little rodfrom the top of the piston."And now we see how we can push the piston up anddown. The next thing is to see how this up and downmotion can turn a wheel round. When I first saw howthis was done, it put me inmind of a knife-grinder'sFly-wheel. wheel, for the treadle andSiron connecting-rod go upand down, and pull theIron connecting. wheel round by the crookedSrod. part called the crank."This is the way it is'reade done in the steam-engine.Acrossthetop of the piston-rod is fastened a piece of iron called the T piece, becauseit makes the form of a T with the piston-rod. The. Tpiece moves up and down between guides, to make it
THE FIRST RAILWVA Y TRAIN. 33always move in a straight line with the piston-rod. Ateach end of the T piece is hung a connecting-rod, andthe other ends of the two connecting-rods are joined totwo cranks on the same spindle, on which a heavy wheelEND VIEW.-T -pieco,i 4 !1 Crank.Road Wheel. F'y-whcel,SI Fly-wheel.Locomotive Engine. Fixed Engine.called the fly-wheel is fixed, so that as the piston-rod,and T piece, and connecting-rods go up and down, theypull the cranks and the fly-wheel round.SIDE VIEW.Travelling, or Locomotive Engine. Fixed Engine."The cranks are generally fixed at the ends of thespindle, and outside the fly-wheel, and then they look morelike handles. When an engine is used for machinery, itis mounted upon brickwork, and turns a fly-wheel; butif used for going on the road, it is mounted on four road-3
34 THE FIRST RAIL WA Y TRAIN.wheels, and the connecting-rod turns two of the road-wheels."Uncle Alfred says, the use of the fly-wheel is notonly to make the engine work with regularity, but alsoto continue the motion, when the arm of the crank is ina line with the connecting-rod; for when the piston is atthe top or bottom of the cylinder, the arm of the crankand the connecting-rod are in a straight line with eachother; and in these positions, which are called the dead-points, the connecting-rod can no more turn the crankthan I could turn a grindstone by standing on the handle;but when a heavy thing like a grindstone is turnedround, if we take our hands off the handle, the grind-"-tone will turn a little way by itself. In like manner theheavy fly-wheel easily turns the crank at the dead-points,that is, where the connecting-rod has no power to turn it."As a heavy fly-wheel will continue to move a littleway by itself after we have left off turning it, so a heavycarriage will continue to move a little way on a railroadafter we have left off pushing it, and therefore the travel-ling engine, when once put in motion, easily turns thecrank past the dead-points. But if the engine at theend of the journey were to be accidentally stopped justat either of the dead-points, then it would be very incon-venient to put it in motion again, for the engine wouldhave to be pushed along till the crank had passed thedead-point." To avoid this inconvenience, all the steam-engines onthe railroad have two cylinders, which are generally placedin a horizontal position, instead of being placed uprightas in the above drawings :* one cylinder works the right-"* See drawings at page 33.
THE FIRST RAILWAY Y TRAIN. 35hand wheel, and the other the left-hand wheel; but bothwheels are firmly fixed on the same spindle or axletree,and therefore one wheel cannot turn without the other.The cranks are put at what my uncle calls 'right angles'to each other. This is a right angle L, and this is theposition of the two cranks; and so when one crank is ina line with the connecting-rod (which is the position inwhich it has little power to turn the wheels), the othercrank is in the strongest position for turning the wheels."The cylinders are generally placed thus:(c) is the cylinder, (T) the T piece sliding between twoguides (G). (c a) the connecting-rod jointed to the Tpiece at one end, and to the crank (K) at the other end."There are a great many ways of making engines; butmy uncle says it is best for me to understand an engineof a simple construction now, and that by and by I shallbe able to understand the most complicated engine.""You have never told us, Fred," said George, "whoinvented this wonderful travelling steam-engine. Didnot Uncle Alfred tell you ? "" Yes, he said," replied Fred, "that the great, if notthe only inventor of the locomotive engine, and of thewhole plan of railways, was George Stephenson. Myuncle told me some very interesting stories about himwhen he was a boy, and what difficulties he had overcomethrough life, which I am sure you would like to hear."3-2
36 THE THERMOMETER.Just as Fred said this, which much excited George'scuriosity to know more of George Stephenson, someschool-fellows called to see Fred on his return home, andto ask the two brothers to go on some expedition withthem. Fred put down the book to go out to welcomethem; but George, before he joined his friends, peepedinto the book, and said in a joyful tone," There are some more amusing things in Fred's book,papa: I can see cotton-mills, iron-foundries, and coal-pits.""Do not look at it now," said Fred, as he left theroom. "I will read some more another time."THE THERMOMETER."How very hot it is !" said Frederick Harmer, as heand his brother entered the parlour on their return fromschool. " I think it is the hottest day we have had thissummer. I do not suppose it can be hotter in the EastIndies!""It does not appear to me to be very hot," said hismother; "I feel cool and comfortable.""Ah !" said Fred, "you have been quietly reading atthis open window, while George and I have been walkingin the hot sun. No wonder, mamma, that you are coolerthan we are. Papa, do you not think the day remarkablyhot ?""I feel the day very warm, certainly," said Mr. Harmer,
THE THERMOMETER. 37"but not so oppressive as I did last Monday. I may bemistaken, however, in the real heat of the day, for lastMonday I rode a great deal, and to-day I have been mostlyengaged in the house.""Well, if people feel so differently," exclaimed Fred,"I do not see how we can ever determine whether oneday is hotter than another. Is there no way, papa, bywhich we can know for certain ?""Try and think if either of you can find any means,"replied his father."I should look at the ditches," answered George, " be-cause they are dried up in very hot weather; and thismakes me think that Fred and I are right about the heatof the day, for I observed as we walked along that theywere all dried up."" That is because there has been no rain lately," repliedMr. Harmer. " One night's rain might fill all the ditches,and yet the next day might be hotter than any of theprevious days.""Well, papa," said Frederick, "the old water-butt inthe garden has shrunk so much that the hoops are all fall-ing off. Does not that show how hot the weather is ?"" No; it only tells us that the weather has been drylately. If you roll the butt into the pond, the water willsoon make the wood swell, although the heat may con-tinue to be as great as ever."" That explains why the servants put the washing-tubsin the pond before using them," said George. " The woodswells and closes up the joints of the planks, so that thetub can hold water.""Yes, papa," said Fred; "I see plainly it is the dry-ness, and not the heat, which makes the wood shrink.
38 THE THERMOMETER.For if it were the heat, the hot water, which is put intothe tubs when the clothes are washed, would certainlyopen the joints by making the wood shrink.""Very true," said Mr. Harmer. "We must think ofsome other plan, then, to determine the heat of theweather. Do you know of anything that alters in size,shrinking or swelling, by heat or cold?"" Water, 1 know, swells by heat," observed Fred."I know that too," said George, " because the waterin our glue-pot boiled over yesterday.""Yes," said Mr. Harmer, "the place that was largeenough for the water when cold was too small to hold thesame water when hot. All other liquids as well as water,and also air and the metals, swell or expand by heat.The poker is a little longer and thicker when it is hotthan when it is cold. If you happen to have an iron ring,the link of a chain, or the top of a large key, that will justgo over the knob of the kitchen poker, you may readilysatisfy yourselves of this. Warm the knob between thebars of the kitchen grate for a short time, and then tryto put the ring over it. You will find that the knob hasexpanded, and that it will not pass through the ring. Youmay try another way. Suppose the ring is so nearly thesize of the knob of the poker that you can very nearly,but not quite, put it over the knob while both are cold.If you heat the ring, it will expand, and may then beeasily slipped over the knob.""How very curious !" said Fred." But, papa, I do not understand how we are to findout the difference of heat on different days by merelyknowing that iron swells by heat."" No; nor did I say that iron was used for that pur-
THE THERMOMETER. 39pose, Fred," replied Mr. Harmer: " fluids are much moresuitable. You know what a fluid is, George ?""Yes, papa; water and milk are fluids.""And so also are oil, wine, and brandy," said Mr.Harmer, " and there are several others. Fred, bring mea small phial, a cork, and along quill, and as you pass thestore-closet, fill the phial up to the brim with brandy."When these things were brought into the parlour, Mr.Harmer cut off the two ends of thequill, so as to make a long tube openat both ends, and boring a hole in thecork, he fitted the quill tightly into it. HotHe then pushed the cork well into the waterneck of the bottle, and by so doingforced part of the brandy into the quill.This being done, he made a mark on thequill even with the surface of the brandy." Now, Fred," said he, " take the phialin your hand, and observe the brandy." HandFred did so, and he had scarcely held shinethe phial a few moments when he ex- Parlourclaimed, "Papa, the brandy is moving!Collarlook, it is rising quite high in the quill!I might hold a piece of iron in my handfor ever, and there would never be anydifference in its size; but the brandy /expanded almost directly that I graspedthe phial. See, now it is standing still.' I" Yes; I will make another mark onthe quill with my pencil," said Mr. Harmer. " Nowplace the phial on the table, Fred.""Will the brandy come down again, papa, now thatFred has taken his hand away ?" asked George.
40 THE THERMOMETER." Look, George, and you may judge for yourself," saidMr. Harmer.George looked at the brandy in the quill as attentivelyas his brother Fred; and they both saw that, after somelittle time, it fell to the first mark Mr. Harmer had made."I see, papa," said Fred, when he observed that thebrandy remained stationary at the first mark, " the upperpencil-mark shows the heat of my hand, and the lowermark the heat of the parlour. I should like to knowwhether the brandy would sink lower in the cellar. Thecellar is much cooler than this room. George, will youcome with me ? and bring a lighted candle with you anda pencil; then we can try." George ran for a candle, fol-lowed by his brother; and when, after a short time, theyreturned, George exclaimed with delight, "Papa, it doescapitally! Look the mark is lower than the parlourmark, and we felt it quite cold in the cellar after thiswarm parlour."Fred seemed as much pleased as his brother, thoughhe looked thoughtful.The phial was then taken into the sunshine, and thebrandy rose higher and higher, but not so high as themark which was made when the phial was held in thehand. When Fred showed his father the mark that hehad made on the quill, which Mr. Harmer said might becalled summer-heat mark, he said he should like to plungethe phial into hot water."Then you must make your tube longer," said Mr.Harmer. " Cut two new quills neatly, and fit the threetogether. I advise you to dip the ends into gum-water,that your tube may not leak.""When this was done, the phial was put into a basin of
THE THERMOMETER. 41hot water, and the brandy quickly rose into the topmostof the three quills."How curious! how beautiful!" exclaimed both theboys; "and how useful! " continued Fred, "for it showsthe increase of heat exactly. If we had had this littlecontrivance during the last week, papa, we could havebeen certain about the heat of the weather. We couldhave watched the brandy each day, and made differentmarks for each day's heat. I think this contrivance of thequills, the phial, and the brandy, might be called a heat-measurer.""Instruments something like this," said Mr. Harmer,"but more exact, and with a fluid more suitable for thepurpose, are, in fact, used as heat-measurers. They arecalled by a name that signifies these verywords, thermo-meters; 'thermo' meaning heat,and 'meter,' measure."" Oh! how I wish we had one," said Fred."Do tell us, papa, how thermometers aremade.""The thermometers in general use," repliedMr. Harmer, " are little glass tubes, with abulb at one end, nearly filled with quicksilver,and sometimes with spirits of wine, which isa liquid something like brandy; and this tubeis fitted into a slip of wood or brass, on whichlines are marked called degrees."" How do they get the quicksilver into thetube, papa ? " said George; " I thought quick-silver was a metal, and are not all metals solidlike iron ? You said just now that fluids showed the dif-ference of heat much better than solid substances."
42 THE THERMOMETER."Yes, so I did, George," replied his father; "butquicksilver, although a metal, is in our climate a fluid.Near the North Pole it becomes as hard as any othermetal, and can be beaten with a hammer, and drawn outwithout breaking. But in the temperate and hot coun-tries it can be poured out like water, although it is nearlyfourteen times as heavy.""Well, that is curious!" exclaimed George." The quicksilver thermometer is most generally used,"continued Mr. Harmer, " because quicksilver will bear agreater amount of heat before it boils than spirits ofwine."" Papa," said George, " I should like you to tell us howthermometers are made from the very beginning.""Well then, George, I will try to explain how theyare made, as you say, from the very ..:... -.. " repliedMr. Harmer. "The workman takes a small glass tube,open at both ends, and melts one end of it in the flameof a lamp till the hole is closed; then he blows at theother end of the tube. The air cannot escape, and there-fore stretches the closed end, which is quite soft, into asmall bulb. He next holds the tube with the bulb overthe flame, but taking care that the heat is not strongenough to melt the glass. By so doing he drives outnearly the whole of the air, because as each particle ofair stretches or expands by the heat, it rises in the tube,and escapes at the open end. Having nearly freed thetube from air, he reverses it, putting the open end of itinto a cup of quicksilver; and now, Fred, what do youthink must happen?"" I should think, papa, that the quicksilver must mountin the glass tube as the tube cools, because the pressure
THE THERMOMETER. 43of the air outside the tube all over the quicksilver in thecup must press the quicksilver up the tube."" Yes, papa. I think Fred must be right," said George,"because it is just like the water rising in the pump-barrel, is it not ? As the glass tube has no air in it, thequicksilver creeps in to fill the empty place."" You are both quite right," said Mr. Harmer, laughing,"though you almost speak of the quicksilver, George, asif it were alive. The tube is not yet, however, sufficientlydeprived of air. The bulb is, therefore, again held over theflame till the quicksilver boils, and then the vapour orsteam of the quicksilver drives out all the air. Before thequicksilver cools, the workman holds the upper or openend of the tube in the flame; and when melted, by givingit a slight twist, he closes the hole. The quicksilver wouldexpand even if there were air in the tube, but not so-readily, because it would have to overcome the resistanceof the air, and therefore it has been contrived to draw allthe air out. The marks are made in this way: The glasstube is first placed in pounded ice, and the place wherethe quicksilver sinks to is marked by a slight scratch, andcalled the freezing-point. The tube is next plunged intoboiling water, and another mark is made called the boiling-point. When the tube is fitted into the frame, this boil-ing-point is marked 212, and the freezing-point 32. Thespace between these points is divided into 180 equalparts, called degrees; and below the freezing-point 32divisions are marked of the same size as those above thatpoint. And now the thermometer is complete, and a mostvaluable instrument it is; for, instead of guessing howhot or how cold anything is, we are able to tell exactly.""I am sure, papa," exclaimed Fred, " that people who
44 THE THERMiOMETER.have such an instrument as that need not dispute whetherone day is hotter than another. I wish you could showus a thermometer.""I should like to show you one very much, boys," re-plied Mr. Harmer. "I dare say our neighbour, Mr.Hervey, has a thermometer. Go to him, Fred, with mycompliments, and beg him to be so kind as to lend me onefor a short time. I think he will have no objection totrust you with it, for you are known to be careful whenthings are lent to you."" Oh, yes, papa," said they, both at once; "I am surewe will take great care not to injure it." And they ranto ask Mr. Hervey to lend their father his thermometer.Mr. Hervey willingly lent the thermometer, and hisson William came with Frederick.It was an excellent thermometer, and marked not onlyon one side according to Fahrenheit's method (the usualway of dividing thermometers in England), but on theother side according to the French method. Mr. Herveyiad written down many interesting remarks of his own:the heat of summer in the East Indies and in England;the cold of winter in Iceland and in Canada; the pointsat which spirits boil and oil congeals; and many otheruseful facts. The boys were much pleased to examine thethermometer, and George was now quite convinced thata metal could be fluid even without heating it over a fire,for he saw the quicksilver roll up and down the tube whenhe moved it as easily as water."You find this thermometer very useful, I dare say,"said Mr. IIarmer to young Hervey." Yes, sir, we often use it," replied William. " Everytime we brew it is frequently plunged into the water, that
THE THERMOMETER. 45F. signifies Fahrenheit's, or the English scale. F CC. signifies the Centigrade, or French scale.2120. Water boils. 2102001900. Brandy boils. I ,174. Spirits of Wine boil. e1270. Tallow melts. io/21100. Summer in East Indies. ISVery hot in England."". Common heat in East Indies |075. Summer heat in England.550. Temperate in England. 500. Common heat of spring-water. S .o430. Olive oil begins to stiffen.L0820. Water freezes. |50200. Very cold in England. 0o5. Winter in Canada.In Iceland, the cold is sometimes 240 below 0.At 400 below 0, quicksilver freezes.the malt may be put in at the right time. Were the heattoo little or too great, the beer would be spoilt. Then
46 THE THERMOMETER.my mother, who suffers so much from ill health, has oftena warm bath, and the doctor orders the exact heat that issuitable for her. We could not tell when we had madethe bath the right heat without the thermometer. Butwill not you show me your thermometer, Fred ? I shouldlike to see it."The boys showed William their father's contrivance,and they amused themselves by adding fresh lines to it.At last George said, " Papa, do you know where quick-silver is found ? ""The largest mines are in Spain; but quicksilver, ormercury as it is also called, is moreover found in Germany,Istria, and elsewhere. The mines in Istria were discoveredin a curious way about three hundred years ago. A greatmany coopers lived in that part of the country; and oneof the men, on leaving his work in the evening, placed anew tub under a dropping spring, to try if the tub leaked.When he came in the morning, he found his tub so heavythat he could not lift it. He was very much surprised,and began to examine the shining and heavy fluid whichwas at the bottom of the tub. It was quicksilver. Thecircumstance was soon talked about, and a company wasformed to search farther and discover the mine from whichthis quicksilver had flowed. In some parts of the rock,the metal was found to run in small streams. In otherparts it was mixed with sulphur or other ores, and it wasthen a solid substance, but easily separated by heat.""I hope, papa," said Fred, "that the man who acci-dentally discovered the quicksilver had some present madeto him.""Yes; he was liberally paid," replied Mr. Harmer."The present depth of the mine is above eight hundred
THE THERMOMETER. 47feet, and it yields a hundred tons of quicksilver everyyear.""I am glad the man was paid," said George; "for,though it cost him no trouble to find the quicksilverspring, I do not think it would have been fair to havegiven him nothing out of all the money that was gainedby the mine, when he was the very first to find it."" How very cold it must be in those countries wherequicksilver freezes !" said Fred; "that is not even markedon the thermometer. I suppose, papa, there is no metalthat expands so much with a small quantity of heat asquicksilver."" Certainly not," replied Mr. Harmer. " We knowthat a great heat is necessary materially to increase thesize of other metals. A piece of iron, measuring a footin length while cold, becomes only one-eighth of an inchlonger when heated red hot. And lead, which is muchsooner melted than iron, still requires a considerable heatto expand it. Have you ever seen a wheelwright put theiron hoop or tire round a coach wheel ? He first makesthe hoop too small to go on when cold, and then placesthe hoop in the fire, by which it is sufficiently expandedto slip on the wheel easily. But even for this smallenlargement great heat is required.""Ah, I see, papa," said Fred; " and then as the hoopcools it must contract and bind the wheel firmly to-gether."" Casks are bound in the same manner, Fred," con-tinued Mr. Harmer, "and masts of ships. So you seethat the knowledge of the expansion and contraction ofmetals is useful in many trades. Now, Fred, take in thethermometer to Mr. Hervey, and thank him for the use
48 THE WINDMILL.of it, and perhaps you can persuade your young friend tospend the afternoon with you."To this proposal William readily agreed, and after thethermometer had been carefully returned, the boys leftthe parlour to amuse themselves in the garden and tool-house.THE WINDMILL.IT was the custom of Mr. Harmer to take his family afew miles from town in the month of May, to spend thesummer in the country. This change was always enjoyedby the young people; for much as they liked the variouspleasures of London, yet with the return of spring camethe thoughts of their country occupations,-hay-making,cricket matches, pony-riding, &c.It was about a month after Frederick and George'sarrival in the village of Sanderstead, near Croydon, thatthey were trying one of their best kites. The kite wasmade of thin tissue-paper, and from its extreme lightness,and the slenderness of its string, it mounted beautifully,ascending steadily higher and higher, until the boys weresurprised at the small speck that it formed against theblue sky."How hard it pulls " exclaimed George; "I scarcelythink the string will hold long. I will let no more out,Fred."George had hardly made this resolution when the string
THE WINDMILL. 49broke about half-way up, and the wind carried the kitetowards a mill, a field or two off.To the great vexation of the boys, the kite pitched andfluttered over the mill till the string got entangled in thesails. The kite was whisked round and round by the sailsbefore they could even call out to the miller to help them;when, however, they had succeeded in making themselvesheard, to their great surprise the mill was stopped in amoment. The miller then took the kite off the sail, andgave it to the boys. The paper was sadly torn, but, asthe frame was still whole, Fred thought it would be worthwhile to repair the kite; and he thanked the miller forstopping the mill."I wish, sir," said George, "you would be so good asto tell us how you could stop those great sails so easily.I thought it would be a very difficult thing, because I haveheard that when the wind is high it blows so violentlyagainst the sails that they will knock down any one whocomes in their way."" So they will, my boy," replied the miller, " and I ad-vise you always to be very careful not to get in their way.Stopping the mill, however, is an easy matter; but, as Iam very busy to-day, I cannot well afford the time toexplain to you how it is done."Fred and George were sorry to hear this, and they werejust going away, when a little girl, who had been standingnear the miller, trying several times to gain his attention,exclaimed, "Pray, dear father, do not send them away;I am sure they are the boys who were so good-natured tome."Upon hearing his little daughter's remark, the millerasked the boys their names.4
50 THE WINDMILL." Frederick and George Harmer," replied Fred."Ah, then," said the miller, "you are the boys whowere kind enough to take care of my little girl in yourfront-court the other day, when a lorse took fright, andran away from a chaise in the road that passes your house.I am very much obliged to you for your kindness to her.To-day is certainly, as I said, a busy day with me; but onegood turn deserves another, and if you like to see my mill,and how I stop the sails, I will show you with pleasure.""Thank you, sir, thank you !" exclaimed both the boysat once; " we should like to see the inside of the mill verymuch indeed."The good-natured little girl looked as pleased as Fredand George, though she did not follow them up the stepsof the mill, but, nodding and smiling, she ran into hermother's cottage, which was near the mill.The miller showed the boys every part of the mill, andthey were both so much interested that they would havestayed much longer if the miller could have spared themany more of his time.Some portions of tho miller's explanations were diffi-cult to understand, because, for parts of the machinery,he used names which the boys were not accustomed tohear. George also was apt to be rather impatient, andto think of one thing while the person speaking to himwas explaining another; but they both learned manythings about the structure and management of the mill,and then they ran home to tell their father what they hadseen and heard."Papa," exclaimed George, as he entered the parlour,"you do not know where we have been this morning.Come, I will give you three guesses."
THE WINDMIZLL. 51"Three guesses " said Mr. Harmer, looking up fromhis book; "a very liberal allowance. Let me see yourhands, George. You have not been to the brick-field,certainly. I should judge, by their appearance, and fromthat white patch on your coat, that you have spent themorning at the lime-kiln, or at the baker's, or in the wind-mill. Ah! I think I am near the mark."" Yes, papa, you are right," said Fred; " we have beenall over the windmill, and the miller has taken a greatdeal of pains to explain everything to us.""But, Fred," said George, "before you tell papa allthe particulars, just let me tell him two or three thingsthat I liked very much, and which I think are very curiousindeed. First of all, papa, do you know that those greatsails, which the miller says are forty feet long, can bestopped directly, by merely pulling a rope ? I could doit; anybody could do it. Next, there is a tiny windmillstuck on the roof of the mill, which turns the great sailstowards the wind, whichever way it blows. There isanother thing, also, that is very clever, though the millersaid it was a very simple contrivance. When more cornis wanted to be put into the hopper to be ground betweenthe great stones, a little bell rings of itself, and then themiller knows that the hopper is empty, and he fills it again.So, papa, the little bell is just as useful as a man standingby to watch, and to call out, as the hopper becomes empty,' More corn, miller, more corn.' "" You must have had a very entertaining morning in-deed, boys," replied his father; "but I should like toknow how all these things are done, George. Cannot youexplain some part of them to me ? "" Not vc:r well, papa, I am afraid," said George, half
52 THE WINDMILL.laughing and half ashamed, "because, though I asked themiller to tell me how the sails were stopped directly Iwent into the mill, yet he did not explain it to me tillquite the last thing; and all the time he was talking ofthe other parts of the mill, I was saying to myself, 'Iwonder when he will come to the stopping of the mill?'I suppose that prevented me from understanding all hesaid to Fred. But, papa, Fred can tell you, I am sure."" Because Fred was so much more attentive, I suppose,eh, George?" said Mr. Harmer. " Well, Fred, I shalllike to hear all you can remember."" So shall I," said George, "for I was vexed with my-self afterwards for thinking so much about the stoppingof the sails. After all, I did not see exactly how it wasdone, for when we went up the ladder to the very top ofthe mill, I was rather afraid of falling, so that I could notattend much to the explanation.""That was unlucky, indeed, George," said his father."I think, papa," said Fred, "that I shall be able toremember and explain the different parts of the mill muchbetter if you have a print of the inside of a windmill.Have you any book about windmills? "" Yes, I think I have," replied Mr. Harmer; "and whileI look for it, Fred, do you put down on a slip of paperthe various things that were done in the mill this morning,and then we shall see if there is any difference betweenyour mill and the prints in the book.""While Mr. Harmer was out of the room the boys triedto remember the different things that they had seen." Write down the stopping of the sails first," saidGeorge."No, no," said Fred, " we must first of all put down-
THE WINDMILL. 53" 1. The wind blows the sails round."2. The sails turn towards the wind, whichever way itblows."3. The corn is ground into flour between the twol:rge heavy stones."4. The flour is sifted to get the bran from it."5. The mill can be stopped whenever the miller likes.""Will you not put down the ringing of that usefullittle bell, Fred ?" said George."If you wish me to do so," replied Fred; "but that isonly a little contrivance; the five things I have mentionedare far more important."When Mlr. Harmer returned to the parlour with the vol-ume he had spokenof, the boys soon /"found out the printof a mill that ex-actly resembledthe one they hadbeen over, andwhich was called asmock-mill, fromsome fancied like-ness to a smock- /frock. In the same _-- Ipage was a print -of a post-mill, so POST-MILL.called from the whole mill turning round on a post. Thewheels belonging to the post-mill were thick and clumsy,because they were made of wood; but in the smock-millall the wheels were light and neatly formed, being madeof iron.
5 THE WINDMILL." Well, papa," said George, " all the wheels that wesaw this morning were made of iron. I could not helpthinking how well they fitted, and how difficult it mustbe to hammer iron wheels into their proper shape. Themill-maker must be a long time making them.""No," said his father; " the wheels are not made inthe way you imagine. The mill-maker, or millwright, ashe is called, first makes a neat wooden pattern exactly likethe iron which he is in want of. The ironfounder pressesthis pattern into a box of sand, and then carefully removesit. A mark is thus left in the sand just the form of thepattern. The ironfounder next pours into the mould aquantity of melted iron, which fills every part of thehollowed sand, and thus an iron wheel is cast as easily asyou cast a leaden dump. Now, Fred, let me see yourlist."1. The wind blows the sails round."" Yes," said George, laughing, "we all know that, butFred is so very exact, papa, is not he? There is onething about those sails though that I do not understand:the wind blows in front of the sails, and yet they go side-ways. How is that? Do you know, Fred ?""I do not think the sails are quite flat," said his brother."They slope a little."" " Yes," said his father, "and Ican easily show you how the windacts upon them; I will cut this- card into four little sails, and puta pin through the middle. Nowblow against the sails, George. They do not turn, becausethe sails are flat, but when I bend one edge down, so asto slope from the wind, see what follows."
THE WINDMILL. 55"The sails turn swiftly round, papa, moving sidewaysfrom the wind, exactly like the real sails of the wind-mill.""Precisely, George. Well, the second thing you ob-served in the mill, boys, was that the sails turned towardsthe wind, whichever way it blew. How was that contrived,Fred ? "" Oh, that is an excellent contrivance, papa, which, themiller told me, saves a great deal of trouble. The roof,or cap of the mill, is separated from the mill itself; thelower edge merely lies on the top part of the mill (bothbeing quite round), in the same manner as the lid of around box fits on the box itself. The roof supports a greatiron spindle or wind-shaft, as the miller called it; and theshaft and the roof will all turn round together on the topof the mill. The vane, which George calls a little wind-mill, is also fixed to the roof. When the wind blowsV--- -- -----against the vane, it makes it turn a pinion. See, George,here is an exact print of this part of the mill, with halfof the cap removed, so that you can see the inside also.The pinion marked P turns in a large toothed ring, R,
56 THE WINDMILL.which, as you must recollect, the miller said was firmlyfixed to the top of the mill. Now, as the pinion cannotpossibly move the fixed ring, it pulls itself round theteeth of the ring, drawing with it the roof, the shaft, andthe sails together."" That is certainly a very useful contrivance," said Mr.Harmer, "and I do not wonder at the miller's sayingthat it saved a great deal of labour; for in the old post-mill, every time the wind changes, the whole mill has tobe turned round on the great post upon which it is built.""Why, how is that done, papa ? " said George.His father pointed to the print of the post-mill, wherea large beam of wood was represented fastened to themill at one end, and supported at the other by a largecoach wheel. "When the wind changes," said Mr. Harmer," it is necessary to raise the steps a little off the ground,and to secure them to the great beam; then two men takehold of the wheel-end of the beam, and by main forcepull the mill round towards the wind.""What a clumsy plan," exclaimed George. "But, papa,there is one thing which neither you, nor Fred, nor themiller has explained. I do not understand how the roofof the mill can be turned round without breaking thewheels in the mill.""I think I know," said Fred; "but, papa, you willexplain it best.""Are you afraid," said his father, " of a hard word,George ? "" Oh, no, papa; I do not think any word hard, whenyou have made me understand the meaning of it."" Now for the hard word then. Look at this print,George. The wheel A, on the upright shaft, is concentric
THE WINDMILL. 57with the lower edge of the room, that is, they have thesame centre.""There is nothing difficult in that word, I am sure,papa, either to understand or to remember," said George." The coloured rings in a kite, and in my target, have thesame centre; and I have often made concentric circles,without knowing they were called by that name."" Well," said his father, "now observe the wheel B onthe wind-shaft, and you will see thatwhen the cap travels round, the wheelB will go round the wheel A, and thattheir teeth must always work together;because the wheel B will always be at /the same distance from the centre ofA. The two wheels can never jam COcE"1TRIC CIRCLE.against one another, nor get away from one another."I see, I see," said George, eagerly; " while the pinionis travelling round outside on the great fixed ring, andcarrying the cap with it, the wheel B inside the cap travelsin the wheel A on the top of the upright shaft. Now,Fred, you can go on to grind the corn.""Oh, I shall not be long about that, George," saidFred, laughing, "now we can turn the sails to the windwhichever way it blows; for the great wheel B must notonly turn the wheel A round, but also any other wheelthat is fixed upon the upright shaft. But first of all,papa, I must tell you about the mill-stones. They aremade of a curious sort of stone, full of small holes, like asponge or a piece of bread; and the miller said they camefrom France, and were called French burr-stones, andwere better for the purpose than any other stone what-ever."
58 THE WINDMILL." And the mill-stones, papa, are very large and heavy,"said George; "for the miller said that one mill-stone wouldsometimes weigh nearly twenty thousand pounds.""I am glad both of you obesrved the mill-stones soclosely," said Mr. Harmer. "A hard, smooth stone wouldpress the corn together, and not cut it sufficiently; anda rough, brittle stone would break, and fill the flour withparticles of sand. The burr-stones are not often broughtto this country much larger than a man's hat; a numberof them are therefore carefully cemented together, andbound with iron hoops, to form one mill-stone. Themethod that is employed in France to split the burr-stones to the requisite thickness, is rather singular.Circular indentations are made round the blocks, atproper distances, and then wedges of willow that havebeen dried in an oven, are driven into the indentationswith a mallet. When these wedges have been sunk to aRoperr depth, they are moistened with water; and, aftera few hours, the several stones that have been markedout are found to be perfectly separated."" That plan must save a good deal of knocking and ham-mering, papa," observed Fred; " but I suppose it can onlysucceed with stones that are porous like the burr-stones."There were some spare mill-stones in the mill, papa,so that we could see that one side ofeach was grooved over just like this."The stone with the little hole isfastened down tight, and the stone"with the great hole is put over it, butnot so near as to touch. The upperstone spins round so swiftly, thatyou can hardly see it move."
THE WINDMILL. 59Binx Fljor j|I LSECTION OF A MILL TURNING TWO SETS OF MILL-STONES."Is the little hole in the lower stone to let the flcurthrough ?" said George." No; I will tell yon the use of that hole presently"'
60 THE WINDMILL.replied his brother. " The upper stone, as it whirls roundover the lower, whirls the flour out from between themboth, into the case that surrounds the mill-stones, anddown a trough fixed to the side of the case. It is neces-sary to keep the stones a little distance apart, for if theytouched one another they would get very hot indeed."" Ah! " said George, " I put my hand into the flour asit came out of the mill, and it was quite warm Buthow do they keep the stones just the proper distance fromeach other, Fred ? "" A strong spindle is put through that small hole in thelower stone, George, and turns the upper mill-stone. Thelower stone, as I said, always remains fixed in one posi-tion; but the upper is fastened to the spindle; and so, byraising or lowering the spindle, you can raise or lower theupper stone, and thus keep the stones at the proper dis-tance apart."" But you have not told us now, Fred," said George,"how the spindle can be raised or lowered."" Gently, gently, George," said Mr. Harmer; "youscarcely give Fred time to remember which are the bestparts to explain first. I dare say he considered it wasmost important to know how the upper mill-stone isturned, before he explained how it is kept apart from thelower stone at the necessary distance, by means of thespindle."" Yes, papa, I was just going to describe how the uppermill-stones are turned. The great wheel G on the uprightshaft U turns the wheel W, which is fixed on the spindleof the mill-stone ; and, therefore, as the upper mill-stoneis fixed to the spindle, it must turn round with the spindleand wheel W. Now, here is the contrivance, George,
THE WINDMILL. 61for regulating the distance of the stones. You will easilyunderstand it, because this part of the mill is drawnseparately on a larger scale. The lower end of the spindleS rests on the beam B, and by turning the screw-nut S N,I -S --Il ^ Upper mill-tone.t Lower mill-stoue.F----- -- __ :Trough.you raise or lower the beam, and the spindle, and the uppermill-stone which is fixed to it. You were so much pleased,George, in watching the corn as it ran out of the greatsquare funnel, called the hopper, into the mill, that youheard nothing of the miller's explanation about the spindleand screw.""No, I know I did not," replied his brother. "I was
62 THE WINDMILL.thinking of something else, and listening to that noise,'Clack, clack, clack.' The corn, papa, ran out of thehopper into a sort of sloping trough, and there it wouldhave made a great heap, and then no more could havecome out; but the trough was made to wag backwardsand forwards, and so jog the corn into the large hole in theupper mill-stone. I know how that was done, papa. Oneend of the trough was fixed loosely upon a pin, and theother was suspended by a leather strap, and leaned againstthe square spindle G-, which just at this part spread intofour thick rods, forming a kind of cage; and so as thesquare spindle turned round, it kept jogging the troughcontinually. I think I can also explain the ringing ofthe bell just before the hopper got empty, because thispart interested me very much."" I should like to hear you try to do so, my dear boy,"replied Mr. Harmer, " even if you do not quite succeed.I have perfectly understood your explanation of the wayin which the corn is shaken into the mill."" First, papa, I must tell you that there is a little armof wood hung on a pin on the edge of the hopper, and abell fastened to the wooden arm (see section, p. 61, A);and if the bell and wooden arm were left to themselves, thearm would fall against the spindle, which, being square,would, as it turned round, jog the arm backwards andforwards, and keep the bell always ringing. This would beof no use, and therefore there is a strap of leather whichprevents this. One end of this strap is fastened to thearm, and the other end to the opposite side of the hopper.When the corn is put in, the strap is kept down by theweight of the corn, and thus the arm is prevented fromfalling against the spindle; but when the corn is nearly
THE WINDMILL. 63run out, the arm falls against the spindle, and then thebell, being jogged, rings directly.""This contrivance is certainly very simple," observedMr. Harmer, "and I agree with you, George, that it is avery pretty one. I am glad you have recollected someparts of the mill so well. What is the next thing onyour list, Fred ? Theflour is sifted to get the bran fromit.' Do you remember, Fred, how that was done ? "- __ .,,_ ..Finest flour. Fine. Coarse. Bran." Yes, papa; it was done by a curious sort of sieve.The sieve was long and round, something like a muff-box,only larger, and the wire was put round it. In someparts the wire was fine, and in some parts coarse. Aspindle went through the middle of the sieve with brushesfastened to it; and so, when the meal was put in, thebrushes were turned round pretty fast, and rubbed theflour through the sieve, and the bran fell out at the end.""N ow, papa," exclaimed George, "we have come tothe stopping of the mill, and I want to hear about thatparticularly, because it is so surprising that these greatsails can be stopped by merely pulling a rope."
64 THE WINDMILL." Not at all surprising," said Fred, " when you knowthe way it is managed There is a great smooth woodenwheel, X, on the wind-shaft,and over it there is a thinS curved piece of iron, withcurved blocks of wood fastenedto it of the same shape. ThisSis called the break, G. When.. ......." the miller pulls the long ropeR, this rope pulls a woodenlever L, to which the break isfastened; and that, of course,pulls the break down upon thewheel. The break rubs sohard against the wheel, that itpreventsit from turning round.And the miller can as easily set the mill going again, forhe has only to let go the rope, and the weight W pullsup the lever L, and lifts the break off the wheel; andthen, if the wind blows, the mill goes again."
THE BROKEN PUMP."COME, George, wake up," said Frederick Harmer tohis brother early one fine spring morning; "we musthave a good day's work in our new garden. The groundis almost as hard as iron, and we had better dig while itis cool. Don't you hear me; don't you understand ?"" Yes, I understand," answered George, in so sleepy atone that his brother quite laughed at him. The laughwoke George a little more, and after rubbing his eyesand gaping a few times, he sprang out of bed, declaringhe should be ready as soon as Fred.When the boys were dressed they went into the gardentogether. The new piece of ground which their fatherhad given to them the day before was an additional pieceto their former gardens. Mr. Harmer had now markedout for their use a large border, twenty-four feet longand nine broad; for he had observed with pleasure thatthe boys had raised many well-grown vegetables andflowers, and that they generally kept their gardens inneat order.The boys determined to plant this new piece withvegetables and fruit trees; but before they made anyplan for arranging the various beds and paths, they in-tended to dig it all over. They began to dig with hearty5
66 THE BROKEN PUMP.good will, but made very little progress, for the groundwas so hard that they could scarcely force their spadesin."This will never do," said Fred, "we shall not dig itup in a week at this rate. We have just two hours towork before breakfast, and we shall have scarcely anypart dug up to show papa. Let me think, what can wedo ? Oh, I know: we will water it, George, to softenthe ground.""I will run to the pump in a minute, and bring thetwo watering-pots," said George; "and you had betterfetch the large spade, Fred."While Fred went to the tool-house,George ran to the pump, but thoughShe could move the pump-handlemore easily than usual, no waterSame out of the spout, and he re-turned to his brother, exclaiming," How vexatious, Fred! we shallnot be able to dig our garden be-fore papa comes down to breakfast-there is no water in the well."" How do you know there is no water ? " asked Fred."Because I have pumped and pumped till I am tired,and I cannot bring up any," answered George." We will go to the well and drop some stones throughthe hole in the cover, and then we can easily tell by thesound whether the well is dry."The boys picked up some small stones, and went to thewell, which was covered over with a wooden lid and lockedwith a padlock. A knot in the wooden lid had fallen out,and they could easily drop the stones through the hole.
THE BROKEN PUMP. 67As they let the stones fall one by one, George was sur-prised to hear " splash, splash, splash.""It is very odd," said he, "that I could not pump upwater when there is plenty in the well. What can bethe reason, Fred ? ""I should think there must be something wrong withthe pump," said Fred; "we will see if we can find out."" But," said George, "how can we find out what is thematter, when we know nothing about the different partsof the pump ? I have never seen the inside, have you ?""Yes; I have seen the inside two or three times,"replied Fred; " and one day last week (I think it was theday you were at my uncle's) papa explained the differentparts of a pump to me, and he allowed me to take outthe bucket, and so I know he will not mind me taking itout now. Look, George, you can see some parts of thepump now these two doors areopen. The pump-handle isfastened to this upright ironrod by an iron pin, and when Imove the handle up and down,the pump-rod, as it is called,goes down and up.""I can see that quiteplainly," said George; "but Iwant to see the bucket youspoke of, Fred."Fred took out the pinwhich fastened the handle andthe pump-rod together, and drew out the pump-rod. Atone end of it was a round lump of wood, with a piece ofleather nailed round it. In the middle of this lump of
68 THE BROKEN PUMP.wood was a round hole, with a little trap door of leatherwhich opened upwards.Pump-rod "Do you call this thing a bucket?"Wood said George; "why, I expected tosee you bring a pail out of thevalv/ pump; this is not like a bucket. Nobucket could hold water with a greathole right through it, Fred."Leather "I know this bucket is not likeWood \ --what people usually carry water in,"replied Fred, " but papa told me thatthat was the proper name, and I heard the plumbers callit so. This lump of leather that covers the hole like alittle trap door, papa told me is called a valve."" What is this thick part of the pipe called, Fred, thatI can see in the lower part of the pump ? " said George."That is called the barrel," replied his brother;"though you see, George, it is more like two quart potsput one above another than a common barrel, which isthicker in the middle than at the top and bottom. Whenwe move the handle of the pump up and down, the bucketmoves up and down inside the barrel, which it fits.""But I wonder the leather round the bucket does notmake it stick fast," said George, "because, when leatheris wetted, it swells and takes more room."" Yes," said Fred, "I know that; and it is on accountof its swelling when wet that it is so useful. The bucketis made just to fit the barrel easily, so that when theleather is wetted it may press softly against the inside ofthe barrel; and the water cannot then run down betweenthe leather and the barrel. But look, this leather is quitedry, and a part of it is rotted away. I dare say that was
THE BROKEN PUMP. 69the reason the pump would not work. Tihis empty place,where the leather is worn off, must have let all the waterthrough, and then no doubt the leather got dry, andwould not press properly against the sides of the barrel.I am almost sure I can mend this bucket with a piece ofan old shoe that you have done wearing, George. I willrun to papa's dressing-room, and ask him if I may try."" Oh, do," said George; "and I will find the shoe bythe time you come back."Mr. Harmer gave the boys leave to try their experi-ment before he sent for the plumber, and the shoe wassoon found. Fred cut it neatly, and nailed the leatherover the bare part of the bucket. The boys then soakedthe leather round the bucket in a pail of rain-water thatstood in the garden, and ran to the pump with the mendedbucket. Fred placed the pump-rod and bucket insidethe pump, and fastened the pump-rod to the pump-handlewith the iron pin."Now, George," said he, "work away, my boy."George began pumping, but he said, " The handle doesnot move half so easily as it did, Fred.""So much the better," answered Fred; "we havemade it fit better then; hurrah! here comes the water,George; pop the water-pot under the spout.""How lucky it was, Fred," said George, "that youremembered what papa told you last week; we have agood hour now before breakfast."The boys carried water-pot after water-pot of waterto their garden, moistening about one-third of the newground. Then they began digging again, and were de-lighted to find how easily they dug up the ground whichwas so very hard till they watered it. After they had
70 THE BROKEN PUMP.been digging some time, George said to his brother,"Though you have told me about some parts of thepump, Fred, I do not in the least understand how thatbucket brings up the water. Did papa tell you? "" Yes, he did," replied Fred: " I am not sure, however,that I can explain it well to you. But when we go into breakfast I will show you the little drawings of thepump papa made for me, and I will try to make youunderstand the matter. Do you think, George, you canrecollect the names of the parts of the pump you saw ? "" Oh, yes," said George. " The handle is fastened tothe pump-rod. At the lower part of the pump-rod isthe bucket, which moves up and down inside the barrel.At the bottom of the barrel is a leaden pipe, about asthick as a rolling-pin, which goes from the barrel into thewell; then there is something like a square leaden boxat the top of the barrel which holds a good deal of water,and the spout sticks out from the box."" That box is called a cistern," said Fred; " but thereis another part of the pump that I have not told youabout, which is very useful indeed. It is called thesucker, and is fixed quite tight at the bottom of thebarrel, and never moves. It is a lump of wood with ahole through it as in the bucket, and a leather trap door,or valve, which opens upwards just like the valve of thebucket.""I am sorry you cannot show me that, Fred," saidGeorge, "but I suppose, as it is fixed inside the barrel,you cannot take it out. Well, when we go in you mustshow me the drawings of the different parts, but I likeseeing the real things best.""So do I," said Fred.
THE BROKEN PUMP. 71"When the boys went in to breakfast, they were muchpleased to tell their father of the success of their experi-ment. They had worked hard, and had dug up a thirdpart of their new ground. After breakfast they bothbegged their father to explain the pump to them, " be-cause," said Fred, "I am not sure, papa, that I shall beable to make George understand.""Try, Fred," said his father. "If you recollect well,I have no doubt you will, and as I have an engagementwith a friend, I cannot stay now."When Mr. Harmer had left them, Fred went to hislittle desk, and showed George the drawings. "Look,"said he, "you must first understand that these drawingsare called sections of the different parts of the pump."" You need not explain that word section," repliedGeorge, "for I know what it means. Anything cutright through the middle is called a section. If I cutthis stick from top to bottom, I make a sec-tion; and if I cut this loaf of bread through,I make a section."" Well then," said Fred, " papa has made Pump-roda drawing of the inside of the pump and itsdifferent parts, that we might understand it,just as if a real section were made from topto bottom."There are the pump-rod, bucket, and I'sucker. The sucker is fixed at the bottom ...i.of the barrel. The bucket with the rodmoves, as I explained to you in the garden, up and downin the barrel, when the pump is worked. Those littleblack things are the valves, which open upward. Tomake me see more distinctly the difference between the
72 THE BROKEN PUMP.drawing of a whole thing, and of its section, papa madethis next little drawing. This is a view of the sucker,not a section of it.S" When the water is above the valve, youknow, the valve must keep close. When thewater is below the valve, the valve must beforced open. When papa explained to me the reason ofthe water rising in the pump, the most difficult thing tounderstand was what papa called the 'pressure of theair.' The air presses on everything......""Why," said George, " do you think that difficult tounderstand, Fred ? I know the air presses against thesails of our boat and pushes it along, and against thesails of the windmill too. I do not think that is difficultto understand or remember.""When papa," said Fred, "was talking to me aboutthe pressure of the air, I thought of the windmill, andthe sails of the ships too; but still that is not the properexplanation of the pressure of the air, for the air presseson everything, not only when the wind blows, but whenthe air is quite still.""What," asked George, "when the day is quite hotand sultry, and we feel no wind at all ""Yes, always," said Fred; "and you can be sure ofthat, George, if you run quickly on a hot day, for youwill feel the air like a slight wind on your face, becauseyou press against the air in running. I tell you what Ithink the pressure of the air is something like, George.Water, you know, is heavy; and in the great sea, in therivers and in the ponds, it presses on the stones, the fish,and the weeds, whether there is a storm or whether thereis a calm. It does not signify in the least whether the
THE BROKEN PUMP. 73wind blow or not, the water presses with the same weighton the different things in the water.""But," said George, " I know that water is heavy, fora pail of water weighs a good deal; but does air weighanything ?"" Yes, it does weigh something, but not nearly so muchas water. If we had a pipe thirty feet high filled withwater, and another pipe of the same size that was thirtymiles high filled with nothing but air, the water in onepipe, and the air in the other, would weigh nearly alike."" But does the air go up so very far above the clouds ? ""Yes," answered Fred, "papa says it goes up evenhigher than thirty miles, but beyond that height it hasscarcely any weight; it is sufficiently near the truth,therefore, to say that there is thirty miles of air alwayspressing on the surface of the well, and upon all otherobjects around us. If we put a pipe into the water, andget the air out of the inside of the pipe, the air that ispressing so heavily outside the pipe on the surface of thewater in the well, will force the water up the pipe.""Well," said George, "I think I can understand nowhow it is. I draw the water from a cup into my mouththrough a straw; I have often done that till I have quiteemptied the cup. I somehow draw the air out of thestraw, and the air outside the straw presses on the sur-face of the water in the cup, and pushes it into the straw.But how does the pump draw the air out of the pipe? "" Why, first of all, suppose, George, the pipe has nowater in it," said Fred, "and suppose the bucket at thelower part of the barrel, as in the drawing opposite. Well,when you lift the bucket, some of the air in the pipecomes through the valve in the sucker into the barrel.
74 THE BROKEN PUMP.As soon as you stop lifting the bucket up, the sucker-valvecloses and prevents the air going back again into the pipe.When you push the bucket down, the air that you havejust got into the barrel pushes openthe valve in the bucket, and goesthrough the valve into the cistern,and then through the spout into theCstern open air. As soon as the bucket hasgot to the bottom of the barrel, thebucket-valve closes, and when youagain lift the bucket, some more aircomes from the pipe through theSsucker-valve into the barrel; and so. you keep on till you have taken allSthe air out of the pipe going intothe well.""And then," said George, hastily, " I know what hap-pens; for while the air is being pumped out of the pipe,the outside air keeps pressing on the surface of the waterin the well, and pushing it into the empty pipe; so that,I suppose, by the time the air is all out of the pipe, thepipe is full of water, and then the water goes throughthe valves exactly in the same way as the air did."" Yes, you are quite right, George," said Fred; "lookat papa's drawings and you will not forgot it. The littlearrows are placed on the side, George, to show which waythe bucket is moving. See, in the next drawing the arrowis pointed downwards. When we lift the handle of thepump, we push the bucket down, and the valves are inthe position shown. In the other drawing, the arrow ispointed upwards. When we pull the handle down, thebucket is lifted up, and the valves are then as shown."
THE BROKEN PUMP. 75"I am almost glad, Fred," said George, "that wecould not pump up the water when we first tried thismorning. I never thought about the inside of a pump be-fore. It is very curiousand very entertaining. Iwonder, Fred, if you andI could make a smallreal pump; I should likeit so very much.""Yes; I think wecould," said Fred. " Wecould make a small pondwell lined with clay forour well, and lay a pipefrom it to our pump. Ihave thought of some-thing else for our garden.""What is that? " said George." A fountain to fall in tiny showers over our plants,like the fountains in the the Zoological Gardens. Onlyours will be very small compared to those.""Oh! that would be beautiful," exclaimed George;"but, Fred, how can you manage that ?""I must ask papa first to lend me the book of platesthat contains drawings of pumps, fountains, and all kindsof things, for I am not sure I know the best way yet;but, George, we will talk of that by and by, for, look, itis near ten o'clock, and we must be off to school, and wehave plenty of work before us for the present, withoutthinking of fountains. Stop one moment while I putthe drawings into my desk, George. Now I am ready."And the two boys started together to school.
NOTHING WASTED." GEOnaR," said Mr. Harmer, early one spring morning," I am going to breakfast with my friend Mr. Franklin,who lives near the London Docks: should you like to gowith me ?"" Oh, yes, papa, I should like it exceedingly," repliedGeorge."Then put on your hat and gloves as quickly as youcan, for we must be at Mr. Franklin's before eight, andit is now twenty minutes to seven."George quickly obeyed, for he liked walking with hisfather, because he was always sure to see and hear some-thing amusing. He was soon ready, and he and his fatherstarted on their walk.It was a fine clear morning, and the sky appeared of adeep blue over the thousand chimneys of busy London.At this early hour few fires had been lighted, and therewas little smoke to dim the bright sky."How pleasant and fresh it feels, papa," exclaimedGeorge; "I am glad I have come with you. But thestreets do not look so amusing as in the middle of theday. A great many of the shops are still closed, andthose that are opened do not look half so gay, with thewindows nearly empty, and the shopmen dusting and
NOTHING WASTED. 77sweeping. I do not think," continued George, laughing,"that I should like to be employed getting shops readyfor customers. Oh! I see something I should like to do.Look, papa, at that boy in the stationer's shop: he hasa kind of watering-pot in his hand, with a hole at thebottom, through which the water trickles. See, the boyis making a figure of eight on the ground. Do stop onemoment, papa; I should like to do that very much."Mr. Harmer stopped at George's request to watch theboy." Papa, what is he doing that for ? ""To lay the dust in the shop, just as the water-cartsare used for watering the roads."" Papa," said George Harmer, "what is that foolishwoman looking in the dust-heap for ? I am sure she canfind nothing worth having there."" Do not be quite so sure, George," replied his father."There are many things that are made use of from thedust and sweepings of the various houses in London.That industrious woman finds it, no doubt, well worthher while to search over these heaps."" Why, papa, she is only picking up little pieces of cordthat can be of no use to any one, and she is even stuffingthose bits of rag and paper into her apron. What canshe do with them? "" She will probably take the cord, pieces of rag, andpaper to a rag-merchant, who will in his turn sell themto a paper-maker," replied Mr. Harmer. " The cord willbe used for making millboards and brown paper. Rag,I thought you knew, George, is employed for makingwriting-paper."" Yes, I know, papa, that writing-paper is made of rags,
78 NOTHING WASTED.after they have been well soaked and beaten in great vatstill they are quite a pulp; but I did not know that suchdirty little pieces of rag as those could be of any use.""The paper-makers can turn the worst coloured rags,"replied Mr. Harmer, " into paper of the most beautifulwhite; but the cleanest rags of course require less labour,and are therefore of greater value."" But what will be the use of the pieces of paper thatthe woman picked up ? " said George. " Can they beused again in paper-making? ""Yes, they are occasionally mixed with the rag pulp,but only for the commoner kinds of paper. Paper thatis made from rag alone is much stronger. But there isanother use for old paper."" What is that, papa ? ""Many of the toys that your sister plays with, aremade of old paper beaten into a pulp. Toys thus madeare much lighter than those made of wood. They aremade in a mould."" What ? is that poor old cow of Lucy's, that has beenbroken in halves, made of paper ?" said George: "it isquite hollow."" Yes; and the reason that paper toys easily split inhalves is, that they are generally made in two separatemoulds, and the two parts are afterwards joined together.Such toys are well adapted for very young children, asthe children cannot be hurt by the paper stuff as theymight be by hard wood.""I think I know something else, papa, that is made ofpaper," said George. " I heard mamma tell Ann to bringup a paper tray the other evening, so I suppose traysmust sometimes be made of paper."
NOTHING WASTED. 79"Yes, all the better kinds of trays are made from paperprepared in the same manner as for toys," replied M/r.Harmer. "Some manufacturers make small tables ofthe same substance. They are beautifully painted, andhighly varnished, and are much admired. The chiefmanufactories of paper ndchi, as it is called, are nearParis, though there are several in this country."George and his father now walked briskly on for sometime. Presently George begged his father to stop onlyfor one moment to observe a man diligently searching inthe road."Papa," said he, "I think that mail must have lostsomething: he is looking about so carefully. Shall weask him ? He has picked up something, and put it intothe pocket of his leather apron; what can it be ? There,now he has found something else. Can you tell what heis doing, papa ?""I think I can guess," replied Mr. Harmer. " He iscollecting all the horseshoe-nails that he can find. Youmay suppose, in a street where so many horses pass andrepass, that many nails may be found."" But, papa," said George, "after they have beenknocked about the street, and the wheels of the carriageshave passed over them, they must be so much bent thatthey can be of no use as nails again; can they ? "" No, George," replied his father, "nor are they re-quired for that purpose. Shoe-nails, from their particularform, are required to be made of very superior iron, orthey would snap in two. They are square, and thick atthe top, and then become very tapering. The blacksmithmakes them from a piece of iron of the same thicknessthroughout, and he hammers it until he has beaten it into
80 NOTHING WASTED.the form he wishes, so that every part of the iron is wellpressed. It is from this circumstance, and from the qualityof the iron which is always employed in making shoe-nails,that they are so valuable even after they have served theirfirst purpose. That man is probably collecting the nailsfor the gunsmiths to make the barrels of the very bestguns."" Oh, papa," said George, "do tell me how they canmake gun-barrels of the old nails which I thought werequite useless."" The nails are placed side by side, with the heads atthe top, about as many as my two hands could grasp, andbound with a small iron hoop just to keep them together.They are next heated till they are slightly melted, andare then violently hammered till they form one mass ofiron. This lump is then again heated, and beaten with aheavy hammer into one long slip of iron; this slip, likea long bit of ribbon, is wound round to form a tube, theedges being made to meet, but not to lap over.""Just, papa, as I could make a tube by winding a slipof paper round a pencil. If I could gum the edges ofthe paper together, and then draw out the pencil, I should,I suppose, have a model of a gun-barrel. But, papa,"
NOTHING WASTED. 81continued George, " how do they manage to make theedges of the iron stick together ? ""By heating the gun-barrel till the edges of the ironare slightly melted, and then giving the coil of iron severalsmart knocks at the top, which presses the edges together.This is repeated several times till each part is welded.The coil of iron is then bored to the size required for theinside of the gun-barrel, and the outside is turned in alathe till the iron is of the proper thickness."" Papa," exclaimed George, " what a deal of hammeringa piece of iron must go through before it becomes a gun-barrel."" Indeed it does, George, and for that very reason gun-barrels made in this manner are much superior in strengthand durability to the barrels of the common muskets;but, from requiring more labour to make them, they aremore expensive."" What a noise that dustman makes, papa," said George,"I can hardly hear you speak. There, he has gone intothat house. I am glad we have got rid of him. I wonderwhat he does with his cart-load of rubbish ? "" I dare say that cart-load is worth several shillings,"observed Mr. Harmer." Oh, is that possible ? Why, I thought the dustmenonly cleared away the small cinders and ashes, which areof no use to any one.""They are of no use for parlour or kitchen fires," saidMr. Harmer, "and therefore some people are glad to getrid of them; but they are very useful for other purposes,nevertheless. There are immense heaps of cinders andashes at Paddington and Camden Town. When they areall properly sorted, the larger cinders are bought byC
82 NOTHING WASTED.washerwomen for heating their boilers; and they pay asmuch as sixpence a bushel for them; that is, about athird of the price of fresh coals. They are also purchasedby brick-makers for heating the brick-kilns. The smallercinders and ashes are mixed with clay for brick-making.They are extensively used for manure in stiff clayey soils." But look, George," said Mr. Harmer, " there is a manpicking up pieces of broken green glass bottles. No onewould think at first that they could be serviceable."" Oh, yes, papa, I could find a use for them," repliedGeorge, quickly. "I have seen broken pieces of glass atthe tops of garden walls. I dare say the man is collec-ting them to be used for that purpose."" He may be doing so," said Mr. Harmer; "but it ismore probable that he is picking up the broken glass tobe pounded for glass-paper.""Paper cannot surely be made of glass," exclaimedGeorge with surprise."No," said Mr. Harmer, laughing, "but a paper thatis used by the carpenters and cabinet-makers for polish-ing wood is called glass-paper, from its being covered withfinely-powdered glass, which is fastened to the paper."" Oh, now I understand," said George. "The powderedglass makes the paper rough."After passing through many narrow streets, Georgeand his father came to an open space, where there was alarge heap of rubbish." Papa," said George, " I dare say some more usefulthings will be collected from that heap. But for whatpurpose can that man fill his wheelbarrow with old tinkettles and saucepans ? Do you think he will find anyone to buy such old worn-out things, papa ? "
THE BAROMETER. 83"Yes, very readily," replied Mr. Harmer. "All tinutensils, as they are called, George, are made of plates ofiron, which have been dipped in melted tin, and thus be-come covered over with a very thin coating of tin; andthose old saucepans and kettles are valuable only becausethey are made of iron." But here we are," said Mr. Harmer, " at Mr. Frank-lin's door, and I think we shall both enjoy our breakfastafter our long walk."THE BAROMETER.OEs evening, Mr. Harmer told his sons, Fred and George,that he intended to take them, the next day, to see Mr.Green ascend in his balloon. As he expected, the boyswere exceedingly pleased, and both exclaimed earnestly,"I hope nothing will happen to disappoint us, papa.-Ihope it will be a fine day to-morrow. Do you think itwill be fine, papa ? "" Yes," said Mr. Harmer; "I did not tell you of myintention till I was almost sure that it would be fine."" But, papa, what makes you almost sure that it willbe fine to-morrow ? " said George."1 can guess," said Fred; "papa has examined thebarometer, and he finds the mercury rising.""But how can he learn from that the state of theweather to-morrow ? " continued George. " I know---2
84 THE BAROMETER.people look at the barometer, to judge, as they say, of theweather, but I never heard anybody explain how theycould judge of the weather by examining it. Will youtell me the reason, papa ? "" Fred," said Mr. Harmer, "can you answer George'squestion ? "" Yes, papa, I think I can," said Fred, "although it isa long time since you explained the barometer to me.The mercury in the barometer rises and falls by theweight or pressure of the outward air or atmosphere, andthe mercury shows the change in the weight of the airwhile the change is going on, and before it can be seenby us. The glass tube that contains the mercury in thebarometer is closed at the top, so that the air cannotpress at the top of the mercury, but the tube is open atthe bottom, and goes into a little box of mercury, just asthe pipe of the pump goes into the well.""Oh! now I think I understand," said George; "theair presses upon the mercury in the box, and forces themercury up the tube, in the same manner as the air pressesupon the water in the well, and forces the water up thepump."" Exactly so," said his father; " and the only differenceis, that mercury being so much heavier than water, theair cannot support or hold up so long a pipeful of mercuryas it can of water. You recollect I told you, that a pipeof air about thirty miles high, or the height of the atmo-sphere, and. a pipe of water of the same size, thirtyfeet *"* More properly, thirty-four feet of water are equal in weightto thirty inches of mercury; but we have preferred to say thirtyfeet, because the numbers thirty feet, thirty inches, and thirtymiles are more easily remembered.
THE BAROMETER. 85high, would be of the same weight. Well, a pipe of mer-cury of the same size, thirty inches high, would weighthe same as the thirty-mile pipe of air and the thirty-feetpipe of water."The name Baro-meter,' means measure of weight.Now I will show you the different parts of the barometer;(a) is the glass tube, which, as yourbrother told you, is closed at the top.(b). The lower part of the tube isopen, and is placed in some mercury, inthe little wooden box (d). The box isclosed, so that the mercury cannot fallout; but the air easily passes into thebox, through the pores of the wood,and pressing on the surface of the mer- acury, forces it up the glass tube. Theair is heavier in fine weather than inwet weather; and so in fine weatherthe air presses the mercury up the glasstube, and in wet weather, when the airis less heavy, the mercury falls."["But, papa," said George, "it seems Ivery strange that the air should weigh Iimore without the rain than with it: -how can that be? " d 1" I have never understood how that L-could be," said Fred, " although I know that the mercurycould not rise, as it does in fine weather, unless the airwere really heavier at that time.""It is a difficulty to many persons," replied Mr.Harmer; "but I think I can make you both understandthe reason, when I tell you that the air can absorb or
86 THE BAROMETER.soak up a great deal of water, and yet the air be quiteclear, just as you can dissolve salt in water, and yet thewater remain quite clear. The cup of water with thesalt in it must certainly weigh more with the salt thanwithout it."" Certainly, papa," said Fred; " but still when the airis very dry and clear, one can hardly believe there is anymoisture in it."" The air in this room is quite clear," said his father,"and yet, I dare say, I can show you that there is moistureeven in this room, although we cannot see it."Mr. Harmer desired the boys to bring him a decanterof cold spring water, and to place it on the table. In afew minutes moisture was condensed upon the outside ofthe decanter, in little drops like dew." It has been found," said Mr. Harmer, " that a cubicfoot of air, that is, a quantity of air one foot high, onefoot wide, and one foot long, is capable of holding twelvegrains of water, without the water being in any way per-ceptible. Now, that cubic foot of air must of courseweigh twelve grains less, if we were to take all the waterfrom it. Infine weather the water is in the air; but inwet weather the water is coming out of the air, and fallingto the ground."The words, Fair,' Change,' Rain,' marked on thecommon barometer, mislead people, because the weatheris not always fair when the mercury stands at 'Fair,' noris the weather always rainy when the mercury stands at'Rain.' Indeed, the proper mode of judging of theweather is not merely to observe how high the mercurymay happen to stand, but to examine whether it is inclinedto rise or fall. If the surface of the mercury be round,
THE BAROMETER. 87it is inclined to rise, and we may generally expect fineweather; if the surface be hollow, it is inclined to fall,and we may then rather except rain. Project- Hollow,igz, or or"The barometer is a truly valuable in- convex, concave.strument to many persons, but particularly ,to sailors, the success of whose operations i idepends so much on the weather. I re-member an interesting account by Dr.Arnott, of the value of the marine barometer, and as Ithink you will like to hear it, I will read it to you."Mr. IIarmer then took down a volume from the book-case, and having searched for the word Barometer in theindex, read the following passage:" The marine barometer differs from that used on shore,in having its tube contracted in one place to a very narrowbore, so as to prevent that sudden rising and falling ofthe mercury, which every motion of the ship would elseoccasion. It has not been many years in general use,and the author was one of a numerous crew who pro-bably owed their preservation to its sudden warning. Itwas in a southern latitude. The sun had just set withplacid appearance, closing a beautiful afternoon, and theusual mirth of the evening watch was proceeding, whenthe captain's order came to prepare with all haste for astorm. The barometer had begun to fall with appallingrapidity. As yet the oldest sailors had not even perceiveda threatening in the sky, and were surprised at the extentand hurry of the preparations; but scarcely were thesepreparations completed, when a more awful hurricaneburst upon them than the most experienced had everbraved. Nothing could withstand it; the sails, alreadyfurled and closely bound to the yards, were riven in
88 THE BAROMETER.tatters; even the bare yards and masts were in great partdisabled. Such, for a few hours, was the mingled roar ofthe hurricane above, of the waves around, and of theincessant peals of thunder, that no human voice could beheard, and, amidst the general consternation, even thetrumpet sounded in vain. In that awful night, but forthe little tube of mercury which had given the warning,neither the strength of the noble ship, nor the skill ofthe commander, could have saved one man to tell the tale."I "What a dreadful storm it must havebeen!" exclaimed George, as his fatherfinished reading. " But how fortunatethat theyhad the barometerwith them!""Indeed it was!" said Fred; "butI think it was equally fortunate forthe crew that they had a wise cap-tain, who consulted the barometer evenwhen the weather appeared so beautiful.Without his watchfulness, the baro-meter would have been useless to them.""I have seen another kind of baro-S meter, papa," said George, "different" from yours. It has a hand like a clock.cHow is that made, for I have neverseen any mercury in it ? "S "No," replied Mr. Harmer; "be-S cause the mercury is enclosed in thewooden case. At the back of the baro-meter you speak of, which is called the wheel barometer,there is a long narrow door, and when that is opened youcan see the whole construction of the barometer, whichis very simple, and easily understood.
THE BAROMETER. 89"The glass tube (a) which holds the mercury, insteadof being straight as that in my barometer, is bent up atthe bottom (b), but the mercury does not run out, be-cause the air presses upon it. A little ball (c) floatson the surface of the mercury, and a thread is fastenedto the ball; this thread is wound once round a pulley(d), and to the other end of the thread a little weight (w)is fastened. When the mercury rises in (a), it sinks in(b); and the little ball, being rather heavier than theweight (w), sinks with the mercury, and, in so doing,pulls the pulley (d) round. To this pulley a hand orindex (e) is fastened, and therefore, as the pulley moves,the hand moves with it."The next morning proved as fine as was expected. Theboys were desirous of seeing the process of filling theballoon, and the party therefore took care to be in goodtime at the pleasure-grounds whence it was to ascend.The boys had seen a print of a balloon in the Ency-clopdia, and in that print there were a great many tubswith pipes coming from them to the balloon; they weretherefore surprised to see no tubs in the grounds, andthey asked their father the reason." The gas, or air, for the balloon," replied Mr. Harmer,"was formerly obtained at the time it was wanted, fromwater, sulphuric acid, and bits of iron put into tubs. Thegas so obtained is called hydrogen gas, and is thirteentimes lighter than common air, and when it is confined inthe balloon, if the balloon and the hydrogen gas togetherdo not weigh so much as common air, the balloon willascend. The hydrogen gas which is burnt in the streetlamps is not so pure as that made in the tubs, but it isnearly as light; and now it is found most convenient to
90 THE BAROMETER.buy the gas of the proprietors of the gas-works, as theballoon has only to be connected with one of the gas-pipcs in the street, and it is filled without further trouble.""Fred was just going to ask his father several questionsabout hydrogen gas, and whether he could not make somewith his father's help, when his attention was diverted byobserving that the balloon was nearly filled, and that Mr.Green was preparing to ascend. At the bottom of theballoon was a little wicker boat or car, hung by ropes toa large net which entirely covered the balloon. In thiscar Mr. Green placed two flags, some bags of sand, amariner's compass, a map, a barometer, and some longropes, with grappling-irons (that is, crooked iron hooks)at the end of the ropes.The balloon being sufficiently filled, Mr. Green steppedinto the car, and everybody wished him a pleasant voyage.He was very cheerful, and not at all afraid, for he had beenup more than two hundred times. By his orders, theropes which held the balloon were unfastened, and held byabout twelve men. Then Mr. Green took a flag in eachhand, and waving them about, called out " Let go " andinstantly the men let go their hold, and the balloon roseslowly and majestically; the people waved their hats andshouted "Huzza! huzza!" while Mr. Green waved hisflags in return.Presently he emptied one of his bags of sand, whichmade the balloon lighter, and it therefore ascended rapidly.In a short time it looked like a mere speck.As the boys returned home with their father, Georgeasked his brother what he thought all the things werefor, that Mr. Green put into the car." I think I can tell the use of them all except the baro-
THE BAROMETER. 91meter," said Fred. "The flags are merely to look gayand cheerful; the sand we saw was thrown out to lightenthe balloon, and make it go up higher; the mariner'scompass and the map must be to tell Mr. Green whichway he is going when he is above the clouds or in a mist;and the grappling-irons are to catch hold of a tree or ahedge, when the balloon comes near the ground, and tohold it steady while Mr. Green gets out of the car; butI do not know what can be the use of the barometer. Ido not think it can be to show Mr. Green what kind ofweather he is likely to have, because people in balloonsare generally up only one or two hours, and we are notaccustomed to such sudden storms in England as thatwhich Dr. Arnott has described. Can you tell us thereason of Mr. Green's taking up a barometer with him?"" Yes," said his father, " I will tell you with pleasure,if you cannot find it out yourselves. As the mercury inthe barometer is kept up by the weight or pressure of theair, do you think the mercury will be as high when thebarometer is carried up in a balloon to a considerableheight above the surface of the earth, as when the baro-meter is on the ground ? ""No, papa, it cannot be," said Fred, "because thereis not so much air to press on the surface of the mercury.There must be all that weight of air less which is betweenthe balloon and the flat ground; and therefore the higherMr. Green ascends, the lower will the mercury fall."" Well," said his father, "and do you see what use Mr.Green may make of the knowledge of that fact ""Perhaps," said Fred, "Mr. Green has observed, orhas been told, how much the mercury falls in a certainnumber of feet; and then, if he had examined the mer-
92 THE BAROMETER.cury at starting, he may, by observing how much it hasfallen, calculate the precise height he has reached. AmI right, papa ?"" Quite right, as to the use of the barometer," repliedMr. Harmer. "The mercury falls more in proportionnear the ground, than at very great heights, because theair is much heavier near the ground. You can imaginethat if a great deal of wool were piled up very high, thewool at the bottom would be pressed much closer togetherthan the wool at the top ; and so it is with the air. Itis on this account that we cannot say the mercury willalways fall one inch for 1,000 feet, although it does sonear the ground; at the height of three miles and a halffrom the ground, it would only fall half an inch for 1,000feet. There are also some other considerations whichmake an exact calculation rather difficult; but it will bequite enough for you to remember that the mercury sinksabout one inch for 1,000 feet, and one-tenth of an inchfor 100 feet. The heights of mountains and variouselevations are frequently taken by means of the baro-meter. Indeed, its use in this respect was discoveredbefore it was employed as a weather-glass. It was easierto observe the change in the mercury when taken to thetop of a mountain than to observe the slight alterationfrom the varying pressure of the air when stationary."The next morning Mr. Harmer read the following para-graph from the newspaper. " Yesterday, at one o'clock,Mr. Green ascended in his balloon from Hampstead, anddescended in safety at Croydon. When he first camenear the ground, the grappling-iron dragged along thesurface till it caught in a bush; just as he had drawnhimself to the bush, it gave way, and the balloon was
THE BAROMETER. 93nearly entangled among some tall elm trees; by promptlythrowing out some ballast, the balloon rose and clearedthe trees, when he again let out some gas, and descendedin a field. He called to a ploughman to catch hold ofthe grappling-iron; but the man was frightened, andcould render no assistance. The grappling-iron eventuallycaught some railings, and Mr. Green having secured theballoon, got out of the car, let out all the gas, folded uphis balloon, and returned to London. As the weatherwas very calm, the balloon continued in sight of Londonalmost the whole of the way, which induced Mr. Greento ascend higher than usual. The barometer at startingstood at thirty inches, and at its highest elevation it sunkto 23o inches, which, it is calculated, indicates a heightof 6,838 feet, or about a mile and a quarter."" How interesting this account is, papa," exclaimedFred, "after having seen the balloon, and had that con-versation with you about the barometer. Oh must yougo to town just yet ? " continued he, as he observed hisfather looking for his hat and gloves. "I wished to askyou so many questions about balloons and barometers.""I can spare you but five minutes, Fred," replied hisfather, " as the omnibus will be here by that time. Whatis it you particularly wish me to answer ? ""Do you know the greatest height that any one hasever ascended in a balloon ? " said Fred." Yes; I believe M. Gay Lussac, a Frenchman, remark-able for his knowledge and accurate observation, ascendedin 1804, higher than any other person has ever done, andhe reached the height of twenty-three thousand feet, ormore than four miles and a quarter above the level of thesea."
94 THE BAROMETER." Oh, papa " exclaimed Fred, " that is higher than thehighest mountain.""No, not higher than some of the mountains in Asia,"replied Mr. -Harmer, " but sixteen hundred feet above thesummit of the Andes. The mercury in the barometer fellto less than thirteen inches. At this extraordinary heightM. Lussac tried a variety of experiments upon air andother subjects, and with as much coolness and exactnessas if he had been in his own house in Paris."" One question more, papa: in what book can I findan account of M. Lussac's ascent ? "" In the Supplement of the Encyclopedia, where thereare many other accounts also of different voyages in theair," replied Mr. Harmer, "some of which, I think, youwill find very interesting."kr-AtC'e~
THE LOCK." jou seem very busy this morning, lads," said Mr.Harmer, as he entered the play-room, and saw Fredstanding upon a chair at a closet, arranging piles of bookswhich George was handing to him from time to time, whilearound them were painting-boxes, desks, models of steam-engines and carriages, boats, bridges, and a variety ofother things." Yes, papa," said Fred: " mamma has given us the useof this closet, that we may keep our books and differentthings together. Lucy is so fond of looking at our con-trivances, that she often injures them if they happen tobe within her reach, and we are not at home to take careof them: mamma says, therefore, that as Lucy is tooyoung to understand the value of them, it would be betterfor us to keep out of her reach those things which we donot wish her to play with. Is not this closet large androomy, and are not these shelves around the three sidesof it convenient ? ""There is one thing, papa, though, that the closetrequires," said George, " before we can be quite sure thatLucy cannot get at our things."" What is that ? " said Mr. Harmer."A lock, papa," replied George. " If you will allowus to put a lock on your door, we intend to buy one."
96 THE LOCK." I will allow you with pleasure," replied Mr. Harmer,"but who is to fix the lock ? ""I think I can," said Fred." Yes," said his father, "as you can use the necessarytools for the purpose, the chisel, the mallet, and screw-driver, and keyhole saw, I dare say you will be able toaccomplish it. I think, however, it would be a good planto try to fix the lock in a plain piece of wood first, andthen you will be less likely to spoil the door."To this Fred willingly agreed. " But what sort of alock am I to ask the ironmonger for ? " said he." It must be a common cupboard lock," said his father,"about four inches long; then the bolt must come outto the left hand, and I should like it to have solid wards.The lock should be sunk inside a hollow cut out of thedoor, and not merely screwed outside. The ironmongerwill know exactly what you want, if you ask for a four-inch, left-hand, inside cupboard lock, with solid wards.""Thank you, papa; as soon as we have placed thethings neatly in the closet, we will go and buy the lock."When the boys went to the ironmonger's, they saw agreat variety of locks, on one of which was written,"The sum of one hundred pounds will be given to theperson who can pick this lock." This made them verycurious to know something about it." It must be a very valuable lock, if it is impossible orvery difficult to pick it," observed Fred to his brother." I have heard a hundred times of locks that have beenpicked by thieves, for the sake of stealing valuable pro-perty."" Pray," said Fred, turning to the shopman, " why can-not that lock be picked ? "