iJ»* LI E> RARY OF THE UN,iy.LR.SITY •> or? Mil NO IS 82,3 Return this book on or before the Latest Date stamped below. University of Illinois Library ■ HAKKY AND LUCY. BY MABIA EDGEWORTH. COMPLETE IN THREE VOLUMES. VOL. I. The business of Education, in respect of knowledge, is not, as I think, to perfect a learner in all or any one of the sciences ; but to give bis mind that disposition and those habits that may enable him to attain any part of knowledge he shall stand in need of in the future course of his life. Locke. THE THIRD EDITION, REVISED AND CORRECTED. LONDON : BALDWIN AND CRADOCK; AND GEORGE ROUTLEDGE, RYDER'S COURT, LEICESTER SQUARE. 1840. %Z3 £ca3Vi^ TO THE CHILDREN OF HER FATHER'S FRIEND, CAPTAIN BEAUFORT, THIS BOOK IS DEDICATED BY MARIA EDGEWORTH. \ [ a 2 7741oO CONTENTS OF VOL. I. Barometer ' PAGE 1 Portable Barometer . 17 Hygrometer 28, 40 Pump Pump Disasters 65 . 78 Air Pump Making Ice M . 87 r 107 Steam Engine . 115,129 Packing up Cotton Manufactory ' . 142 . 152 Gas-lights . 178 Matlock . , 189 Journey . , 206 Etruria . , 217 Pyrometer 238 The Garden - 247 Boating Party . Windmills 270 287 Journey resumed $ SOI PREFACE; ADDRESSED TO PARENTS. These volumes are intended for young people from the age of ten to fourteen. They complete the series of " Early Lessons ;" an humble work, from which no literary fame can be acquired, but which I have been most desirous to complete, from the belief that it will be more useful than any other in my power. I have had another motive for finishing it; one which, though it may be no concern of the public, I may be permitted to name. " Harry and Lucy" was begun by my father, above fifty years ago, for the use of his own family, and published at a time when no one of any literary character, excepting Dr. Watts vni PREFACE. and Mrs. Barbauld, had ever condescended to write for children. That little book was, I be- lieve, the very first attempt to give any correct elementary knowledge or taste for science in a narrative suited to the comprehension of children, and calculated to amuse and interest, as well as to instruct. Finding, from experience, that it answered the intended purpose, my father con- tinued the book at intervals ; and in the last part, published in 1813, I had the pleasure of assisting him. He then communicated many ideas for the completion of his plan, which I thought too valu- able to be abandoned. I considered that a full knowledge of his views, and long habits of ac- quaintance with his mode of teaching mio-ht enable me to do justice to his plan, though I was aware of the difficulty of combining ingenious with practicable illustrations, and still more sensible of the accuracy requisite for elementary scientific instruction. The want of his mind working alono- with my own, I knew must be in this attempt peculiarly felt; but I have been encouraged to persevere by the assistance afforded me by his and my own scientific friends. To name these kind and able friends; would gratify my vanity and o TREFACE. IX might ensure the confidence of parents ; but it would, perhaps, have more the appearance of ostentation than of candour, and might leave others responsible for errors which may have escaped the most careful revisal. I have endeavoured to pursue, in this Conclu- sion of Early Lessons, my father's object in their commencement — to exercise the powers of atten- tion, observation, reasoning, and invention, rather than to teach any one science, or to make any advance beyond first principles. The essential point is to excite a thirst for knowledge, without which it is in vain to pour the full tide even to the lips. As Dr. Johnson said to Boswell, when he was describing the pains his preceptors had taken to give him learning — " Sir, anybody can bring a horse to the water, but who can make him drink ?" Consistently with the sort of instruction to be conveyed, it was impossible to give as much of the amusement arising from incident and story in this book as in some others. But the varying occur- rences of domestic life, the frequent changes of scene, and the different characters of the children, with all their hopes and fears in the pursuit of X PREFACE. their own little schemes and experiments, will, I hope, produce sufficient action to create interest, and to keep awake attention. No pernicious sti- mulus has been given, no deception or cajolery employed to effect our purpose. All attempts to cheat children, by the false promise that they can obtain knowledge without labour, are vain and hurtful. The gods sell everything to labour, and mortals, young or old, must pay that price. The wages of industry should, however, be rendered as certain as possible; for the pupils will exert themselves in proportion to their hopes that their efforts will be recompensed by the plea- sure of success. I have taken all the precautions in my power to secure to each effort of attention its just reward. Much that would be tiresome and insufferable to young people, if offered by preceptors in a didactic tone, will be eagerly accepted when sug- gested in conversation, especially in conversations between themselves. In these there is always a certain proportion of nonsense : an alloy which is necessary to make sense work well. Children can go on talking to one another much longer than they can bear to hear the address, however PREFACE. XI wise or eloquent, of any grown person. Young people of good disposition learn with peculiar ease from each other, because the young teacher has not forgotten his own difficulties : knowing exactly where they lay, he sees how to remove them, or to assist another over the obstacles. The great preceptor, standing on the top of the ladder of learning, can hardly stretch his hand down to the poor urchin at the bottom, looking up to him in despair ; but an intermediate com- panion, who is only a few steps above, can assist him with a helping hand, can show him where to put his foot safely ; and now urging, now encou- raging, can draw him up to any height within his own attainment. The system of mutual instruction can be still more advantageously pursued in teaching the ru- diments of science than those of literature, and may be extended even to higher branches of in- tellectual education. Upon this principle, in the following volumes, the young brother is employed to teach his sister what he has learned, either from his father or from books. Harry's abilities and knowledge will perhaps appear a little above his age ; but this the reader Xll PREFACE. must excuse, and attribute, as he pleases, to edu- cation, or to accident, or to natural genius. Harry will not be disliked because he is not pedantic ; and he has some redeeming faults and foibles, which save him from the odium attached to a per- fect character, and from the danger of beino- thought too good to be natural. Lucy, on the other hand, may at times seem too childish and volatile; her respect for accuracy not being at first much greater than that of the sailor, who said, « We'll not quarrel for a handful of degrees." But these faults produce the non- sense and the action necessary to relieve the reader's attention. As to the danger and the pe- nalties of her becoming an affected scientific ladv, it is left to her mother's and her own good sense and good taste to guard against that evil. All that can be said or thought upon the subject by the other sex is comprised in the Edinburgh wit's declaration — " I do not care how blue a lady's stockings may be, if her petticoats are but lono- enough " My father long ago foresaw, what everybody now feels, that the taste for scientific, as well as literary knowledge, which has risen rapidly, and PREFACE. Xlll lias spread widely, would render it necessary to make some provision for the early instruction of youth in science, in addition to the great and suc- cessful attention paid to classical literature. In public establishments, alterations, even when felt to be requisite, must for many reasons be tardy ; much, in the mean time, may be prepared by pri- vate instruction. It has been feared by some that the general diffusion of knowledge will tend to damp the energy of genius; and that original invention will decline, in consequence of increased cultivation. This might, perhaps, be the consequence of inju- dicious cultivation. If the acquisition of a great quantity of learning of all kinds, or of any kind, were made the sole and ultimate object, the mind would »be oppressed, and invention extinguished under the mass : but of this there is no danger if the faculties be proportionably exercised, and if the pupil be enabled to arrange, and above all to employ, his knowledge. In science, the hope of future discoveries, and the ambition to invent, are great, natural, and never-failing excitements to voung and old. That very ingenious and very mysterious phi- XIV PREFACE. losopher, Dr. Hooke, speaks somewhere in his works of an algebra by which he could determine what things are possible or impossible to perform or to invent. Without perfectly crediting or per- fectly understanding this veiled prophet, we may hope and believe that the inventive power may be assisted and improved by exercise, by reasoning and by judicious experiments. Many admirable observations on the nature and conduct of the un- derstanding, on the causes which have prevented our advancement in knowledge, and on the habits of false reasoning, prepossessions, and prejudices, which enslave and disable our faculties, are to be found in the works of Bacon and of Hooke, of Locke, Stewart, and Playfair. These observa- tions should not be suffered to lie dormant in books, the admiration only of the learaed; nor should we be content with merely citing them occasionally, to adorn our writings, or to point our conversation. Metaphysics, after being too much in fashion, have been thrown aside too disdain- fully, and their use and abuse have been con- founded. Surely it would be doing good service to bring into popular form all that metaphy- sicians have discovered, which can be applied to PREFACE. XV practice in education. This was early and long my father's object. The art of — teaching to invent I dare not say — but of awakening and assisting the inventive power by daily exercise and excitement, and by the application of philo- sophic principles to trivial occurrences, he be- lieved might be pursued with infinite advantage to the rising generation. I have now stated all the objects of this book : how far they have been accomplished must be left to time, and parents, and, above all, to children to decide. MARIA EDGEWORTH. May 3 Is/, 1825. HARRY AND LUCY. BAROMETER. " Mamma, do you recollect, two years ago, when my father was explaining to us the barometer and thermometer, and when he showed us several little experiments ?" said Lucy, and she sighed. "Yes, my dear, I remember that time very well," said her mother; "but why do you sigh?" " Because I was very happy then," said Lucy. "And are not you happy now, my dear?" "Yes, mamma, but not so very happy as I was then, because now I do not go on with Harry as I used to do." " How so ? I hope that you have not had any quarrel with your brother ?" " Quarrel ! oh no, mamma, it would be impos- sible to quarrel with Harry, he is so good-na- tured ; and he is as fond of me as ever, I believe. But yet, I do not know how it is, we do not suit each other quite so well as we did. We are not so much together; I do not know sll he is doing, nor go on with all he is thinking of as I used to do." B Z BAROMETER. " My dear Lucy, you and your brother have been learning different things for some time past ; and as you grow older, this must be ; your differ- ent employments must separate you during a great part of the day ; and so much the better, you will be the more glad to be together in your hours of amusement. Do not you find this ?" " Yes, I do, mamma," said Lucy, " but — " and after this but she sighed again. " But now we are not amused always in the same way. Harry has grown so excessively fond of mechanics, and of all those scientific things, which he is always learning from my uncle and papa." " I thought, Lucy, that you were fond of those things too ?" said her mother. " So I am, mamma; only I am not nearly so fond of them as I was formerly : I do not exactly know why ; but, in the first place, I suppose, be- cause I do not understand them now nearly so well as Harry does : he has got very far before me." " True," answered her mother, " you have been learning other things, which it is more necessary for a girl to know." " Yes, mamma, I remember your saying just after that happy barometer time, that I thought of nothing but experiments ; papa said, that must not be. Then I was not allowed to go into his room with Harry in the mornings. However, I BAROMETER. 6 learned more of arithmetic, and drawing, and dancing, and music, and work." " And you grew fond of these ; so much the better," said her mother. " This does not make you less happy, does it?" " No, no, mamma; hut then came the time when Harry and I were quite separated. That long — long — long time, when you were ilJ, mamma, and when I was at my aunt Pierre- point's : while I was with her, I read nothing but stories and poetry, and I heard my aunt and people who were there reading plays. She used to praise me for understanding w r it, and for repeating poetry. Then I grew very fond of them. But Harry is so grave always about wit, he never understands it at first ; and at last he says, * Is that all ? ' — As to similes, they always interrupt him." ? They interrupt him ! " said her mother, " per- haps, Lucy, you interrupt him." (t Sometimes, perhaps, I do, mamma ; but he always finds out that similes are not exact. This is very provoking. I wonder why he is so much fonder of exactness than I am." " Probably because in science, which he has been learning,* he finds at every step the use, the necessity of exactness. He could not go on with- out it in measuring or in reasoning." " Mamma, I understand the use of exactness b 2 BAROMETER, in some things. In drawing in perspective, and in proportion, by a scale, as you taught me. Harry came to me the other day, and asked me to draw a cart for him ; and I was glad to find that I could help him in something." " And I dare say he will be glad to help you in his turn. You each know different, things, which you can learn from one another, and in which you can be of mutual assistance. This is just as it should be between friends." " Thank you, mamma, you make mc feel happy again. I will ask Harry to bring me up to him in all he has been learning, as fast as pos- sible, that we may go on together as we used to do, if you have no objection, mamma." " Do so, my dear Lucv ; but I warn you, that you should not expect to go fast ; you must be content to go slowly, and you must submit to be inferior to your brother for some time. This may mortify you, my dear, but it cannot be avoided, you must bear it." " Very well, mamma, I can bear it. But mother," said Lucy, hesitating a little ; " there is one other thing I want to say, befoie I can be quite happy." «« Say it then, my dear : what are you afraid of? — Not of me, I hope?" " Oh ! no, mamma, not afraid of you ; but I am not sure that the person, who said what I BAROMETER. want to tell you, would like that you should know that he said it ?" « You can tell me what was said, then, without telling me from whom you heard it. Cannot you, Lucy V « I can, and I will," said Lucy. " Then you must know, mamma, that one day, when I was at my aunt Pierrepoint's, she was telling somebody that papa used to teach me scientific things, along with Harry ; but that, since I had come to her, I had not learned any thing of that sort. And — now it comes, mamma, the gentleman, who is not to be named, laughed." " Well, there was no great harm in that." " No, mamma ; only that he laughed in a particular sort of way, scornfully. And he said, that it was well for me I had left off such learning ; that I should be a much more agreeable woman without it; that ladies had nothing to do with science, or ought to have nothing to do with it. He said, that scientific ladies are always displaying what they know, or what they do not know. Those were his very words. He said, that scien- tific ladies were his abhorrence. And he looked as if he abhorred them terribly. I was very sorry at the time, that he knew papa had taught me any thing along with Harry. I was ashamed and frightened, and I thought it was all wrong. But now that I am come home I think, that it was all O BAROMETER. right ; for I see how much papa likes that you should know the scientific things that he is busy about, and how happy it makes you ; and I want to go on again with Harry : only I wish,, mamma, that all people were of the same opinion about this." Her mother smiled, and said, " That can never be, my dear Lucy : you will find many people have different opinions upon this subject. But all will agree with your nameless gentleman, that when women pretend to understand what they do not, whether about science or any thing else, they are absurd and ridiculous. And if they talk even of what they understand, merely to display their knowledge, they must be troublesome and dis- agreeable. Therefore they should take care not to do so. They should be particularly cautious of talking on scientific subjects, because they seldom obtain accurate knowledge ; they are, therefore, likely to make mistakes, and to be either troublesome in asking questions, or ridicu- lous in showing ignorance and conceit." " That is," said Lucy, ** if they set up for being scientific ladies." " Yes, if they do that, they must take the con- sequences, they will be disliked," said her mother. " But then, mamma, I am so much afraid of being abhorred. Even if they are not conceited, will they be abhorred, mamma?" BAROMETER. 7 * Not by persons of sense, my dear," said her mother. " As far as I can judge, I think that sensible men would be ready to assist any un- affected, unassuming woman, who really wished to inform herself, and would like her the better for being interested in their conversation, their writ- ings, and their pursuits." ec I hope, then, mamma, that I shall be an unaffected, unassuming woman." '■' I hope so, my dear chiid," said her mother, " If your father did not hope so too, he would never teach you any more on these subjects." " I should be very sorry for that," said Lucy. " Yes, I think you would, my dear : for, even with your little experience, you feel that there is a real pleasure in going on, as you say, with your brother." " That I do, indeed, mamma." " As you grow older," continued her mother, " you will perceive, that, by acquiring knowledge, women not only increase their power of being agreeable companions to their fathers, brothers, husbands, or friends, if they are so happy as to be connected with sensible men, but they increase their own pleasure in reading and hearing of scientific experiments and discoveries ; they ac- quire a greater variety of means of employing themselves independently, and at home. But, above all, the acquisition of knowledge not only 8 BAROMETER. enlarges but elevates the mind, by filling it with admiration and gratitude towards that bountiful Providence who has established such wise laws for the welfare and preservation of the world." " Yes, mother," said Lucy ; and, after a pause, in which she re- considered all her mother had been saying, she returned to what still a little alarmed her imagination. " But yet, mamma, I feel afraid of being abhorred; and if the acquiring knowledge should make me vain — there is the danger. " " There is the danger to be sure," said her mother. " But, as far as I have observed, ignorant women are as vain, and often more so, than those who are well informed ; and now, when almost, all are so educated that they have a taste for literature, and some acquaintance with scientific subjects, there is less danger that any should be vain, of what is no peculiar distinction." " Oh, mother, I will take the greatest care," said Lucy ; " you shall see, as I grow up ; and thank you for explaining all this to me." " Perhaps, my dear, part of what I have been saying is rather above your comprehension?" " No, mamma ; not at all. If it is not con- ceited to say so, I think I understand it all perfectly well ; and now I know what is ricrht and wrong, and my mind is settled ; and I am happy again, and very glad that I may have the pkasure of learning again from papa ; and, above BAROMETER. 9 all, glad that 1 may go on again with Harry. And here he comes, mamma ; I see him from this window, coming along the path from my uncle's. Oh, mamma ! he has a great walking stick in his hand, and he is hobbling like an old man of an hundred and ten." " I hope he has not hurt himself," said her mother, coming to the window. " No, mamma, I believe lie is only in play. There ! the old man is running as well as ever he did in his life ; and I will run and meet him." As soon as Lucy was near enough to make her voice heard, she asked her brother why he walked with his uncle's walking stick ? as she supposed it to be. " It is not his," said Harry, " it is mine ; my uncle has given it to me." " Yours ! and it is quite new ; I never saw it before. How beautifully varnished ! and what a pretty head ! But why did my uncle give it to you, Harry ? It would be of use to him, and it will be of none to you," said Lucy. " There you are mistaken ; I beg your pardon, Lucy. It will be of as much use to me as it would be to him, and of the same sort of use," said Harry. i( Same sort of use !" said Lucy ; " but of what sort ?" " Guess," said Harry. <( 10 BAROMETER. " I suppose you mean in play, to act an old man, as you did just now ?" No in earnest useful/' said Harry. What can you do with it ?" said Lucy ; " for you are too young to walk with it, and too old to ride upon it." " Too old ! to be sure I am," said Harry, in- dignantly ; " I have not ridden upon a stick these hundred years. Guess again." Lucy now wanted to examine this wonderful stick more closely, in hopes of discovering what its merits might be, but Harry seemed unwilling to let it out of his hands. " Oh ! I know what it is. It is full of money. It is like the staff which the man had in the trial in Don Quixote, which Sancho Panza found out was full of money, because he would not let it out of his hands." " I do not in the least know what you mean," said Harry, " for there is no money in this." " Then let me look at it ; I will not run away with it. How heavy it is," observed Lucy, " what wood can it be made of ? — This outside seems to be mahogany, but I never felt any so heavy. It cannot be all wood ; it must be hollow T , and there must be something withinside of it." " Stop ! stop ! do not shake it ; do not turn it upside down ; you will spoil it," cried Harry. w Ho ! ho ! then there is something withinside BAROMETER 11 of it. I have found that much out," said Lucy ; u and you say, ' Do not turn it upside down/ like the words on the box of glass that came last week ; ' Keep this side uppermost? So I guess that there is glass within your stick. You smile, there is ! Glass ! — Then perhaps it is a spy-glass, — a telescope? — a magnifying glass? a microscope ? No, none of these ? What can it be ? Of what use can glass be in a walking stick, Harry ?" " Of a great deal, as you will acknowledge when you find it out. Guess again," said Harry ; " it is a thing that you have seen." " But I have seen so many things," said Lucy. " And of which you know the use," said Harry. u But I know the use of many things ! Tell me a little more," said Lucy ; " what is it used for T* " For weighing something,''' said Harry ; " stay, I am not sure that it is quite fair to say it is used for weighing a thing, and yet it is something." " 1 know now," said Lucy ; " that motion you made with your hand up and down against the air, told me. The something that it is used for weighing is air, and it is a barometer." u Now you have found it out," said Harry. w And now I know what makes your stick so heavy," said Lucy. " The quicksilver— the mercury. I remember feeling the weight of mer- cury, when papa put into my hands two cups of the same size, one full of water, and the other full 12 BAROMETER. of mercury. How stupid I was not to think of this at first, and not to guess it was a barometer !" Harry now showed where his walking stick opened, and he showed her withinside of it a barometer and thermometer ; he explained to her how the quicksilver was screwed up tight, so as to prevent it from shaking. He told her this was called a portable barometer. " Yes, it is portable," said Lucy ; " it can easily be carried from place to place. It must be convenient to travellers. But is it in any other way better than the barometer which hangs up in papa's room, or than that which stands upon three legs in my uncle's library?" Harry said, that he was not sure that it was better for common use, to show the chancres of the weather; " but this," said he, " is not merely a weather-glass, as barometers are sometimes called. This is intended for another purpose." ff What other purpose ? " said Lucy. " First, let me tell you why my uncle gave it to me," said Harry ; " because he was pleased with my having taken pains, two years ago, to understand the barometer, and with my remem- bering it now. Then he bid me try to find out the particular use of this portable barometer." " And did you, Harry ? " " Yes, but I was helped. My father, who was present, put me in the right road. I was very BAROMETER. 13 stupid at first. My head went quite off the wrong way, but my father was very patient, and brought it back again, and set it upon the right road. Still I was very slow. My uncle thought I should never find it out. He said it was too difficult, and that my father had better tell me. But papa said he was almost sure that I should find it out myself. This encouraged me, and I tried and thought again, and my uncle left off walking up and down the room fretting. He was so good as to be patient too." " That was kind of him," said Lucy; " I know it is very difficult to be patient with people, if they are slow in finding a thing out, when one knows it all the time. One longs to tell, or to push them on to it." " Papa did not push me," said Harry, " that would have thrown me down ; but he pulled, he helped me on gently, step by step, as he does so nicely ; and he let me find it out at last quite by myself." Well, then, you can do the same for me, Harry." I will try," said Harry. Thank you. But first let me tell you all that I have been saying to mamma, and all that mamma has said to me." She repeated it all, as well as she could, ending with, " Mamma tells me that I may go on with you, Harry, as we used to do ; and she said she te a (( 14 BAROMETER. thought that yo i would be so kind as to bring me up to you in all you have been learning." " I will try/' said Harry. " I hope I shall not be very stupid," said Lucy. u No, no, Lucy, I dare say you will not ; do not begin by thinking you will, that is a very bad way ; because then you go on, thinking you are afraid you will be stupid, instead of attending to what is asked and said to you. Now, Lucy, sup- pose you were at the bottom of a deep well." " If I were at the bottom of a well, then I should find out the truth ; because you know the common proverb, as Mr. Cranbourne said, that truth is at the bottom of a well." " Nonsense," my dear Lucy, cried Harry ; " now if you go to your wit, and what Mr. Cran- bourne says, I cannot attempt to talk to you about the barometer." " Well, I will be very attentive," said Lucy. " Suppose, then, I was at the bottom of a well. But should not I be drowned?" added she, in alow voice. " Very true, I should not have said the bottom of a well, but the bottom of a deep pit," said Harry. " Oh, that is another affair," said Lucy, M I like that better. Now, then, I am at the bottom of a deep pit." " Now, then, which do you think would press the heaviest, the air at the bottom of this pit, or the air at the top of a high house ?" BAROMETER. 15 " I think it woald press heaviest at the bottom of the pit/' said Lucy. " Why ?" asked Harry. * Oh ! my dear, such an easy question," said Lucy. " Well, answer it at any rate," said Harry. " Because, in the bottom of the pit, the air in the pit is added to the air that is above the pit, and also you must add all the air that reaches to the top of the house." " I believe you understand it. Suppose you took this barometer to the bottom of the pit, do you think that the mercury would rise or fall ? My dear Lucy pray think before you answer." Lucy thought, and answered : ** I think it would rise at the bottom of the pit." " Right ; now if you took it to the top of a high house, would it rise or fall ?" " I think it would fall," replied Lucy. - Why ?" said Harry. " Because then there would be less weight pressing upon the quicksilver in the cup, and therefore less quicksilver would be pressed up into the tube." " Very well indeed, Lucy ; I see you remember all papa taught us about the barometer. Now suppose the pit was sixty feet deep, and that the house was forty feet high. Forty and sixty make a hundred, you know." " To be sure," said Lucy. « Well?" 16 BAROMETER. " Well," said Harry, " I must go slowly. Suppose that you observe exactly how much the quicksilver falls, when you take it from the bottom of the pit to the top of the house,, you would have a measure by which you could judge of the whole height and depth." e( I see I should," said Lucy ; " I see ! I see the use of your barometer, and it is very useful." But you do not see all yet," said Harry. By marking this you would not only know how much the quicksilver falls in that hundred feet ; but by dividing it, and making a scale, you might know the same thing afterwards, in any number of feet, in any height to which you might take the barometer ; and by this you would have an easy way of measuring the height of mountains." " Very ingenious ! very convenient !" said Lucy. " Now I understand the use of your portable barometer perfectly." "■ Not perfectly," said Harry. " There is a great deal more to be learned about heat at different heights, and rarefaction of the air. But I will not puzzle you with that, especially as I am not clear about it yet myself. But this is the general notion, which papa says is quite enough at first.'* " Quite enough for me," said Lucy. " Thank yon, Harry, for telling me no more." 17 PORTABLE BAROMETER. " I wish ! oh how I wish !" cried Harry, AIR PUMP. ** Now, brother, for the air pump," cried Lucy ; " as you used to say ' Now, papa, for the baro- meter.' ' " My uncle," said Harry, " has been so good as to lend me his portable air pump to show you. Was not it good of him to lend it?" "Very good, indeed," said Lucy; "and how convenient to have so many things portable ! Portable barometer, portable hygrometer, portable air pump.'' " Now, Lucy, recollect what was the great thing to be done in pumping," said Harry. * Was not it to make a vacuum ?" said Lucy, hesitating, as if she was afraid of making a mistake. " Yes, to be sure, my dear," said Harry. " Be quite certain about that." " I am quite certain," said she ; " I was only afraid to say it at first, lest I should not be right." " But do not be afraid. When you know a thing, know it very firmly. The truth cannot alter between yesterday and to-day ; nor can the truth ever alter, you know." " That is a great comfort," said Lucy. " Was 88 AIR PUMP. not it Boyle who invented the air pump, or was it Torricelli ?" " Neither/' said Harry ; " it was that poetry you repeated, which put that mistake into your head. And when once one has got any thing wrong into one's head there is no getting it out again. But you are partly right. Boyle im- proved the air pump very much, and it is some- times called the Boylean vacuum, that is, Boyle's vacuum. But Boyle was too honest a man to claim for his own the first vacuum. I mean the first making use of it for the air pump. He knew, and always said, it was Otto Guerick's invention." " Well, I dare say it was," said Lucy ; " you need not say any more about it. I do not care much who made the first vacuum, nor who first made use of it for the air pump." " You do not ! Lucy, my dear, consider what you say. Suppose I had invented the air pump, or something as great, would you, my sister, like that somebody else should take from me the honour and glory of the invention?" " No, I should not," said Lucy ; " but you are my brother, and alive ; and to be sure I should be anxious that you were not robbed of the glory. But those other people, Mr. Otto Guerick and Mi*. Boyle, are nothing to me; besides, they have been dead and buried long ago, and what signifies it now to any body V AIR PUMP. 89 «* It signifies a great deal," said Harry. " Sup- pose it was my father, or my grandfather, or my great grandfather, should not I care? would not you? Then so would Otto Guerick's, or Boyle's children, or grandchildren, or great grandchildren, if there are any living. And there is a great family of Boyles, I know ; and do you think that for the world they would give up the Boylean vacuum ?" w I suppose not," said Lucy. " But now let us go on to the air pump itself, and the vacuum, let it be whose it will." " So we will," said Harry ; " but, before I show it to you, remember, that what you are going to see is a pump for pumping out air, not for pumping up water. So put water quite out of your head." " I have put water quite out of my head. I understand that the air pump is to pump out air. But, brother, before you begin, let me say one thing." " Say it then, if it is not poetry." " No, it is only that I think a pair of bellows is a sort of air pump. Hey, Harry?" " Well, that is not foolish, Lucy. You may call a pair of bellows a sort of air pump ; only that bellows never could be a right air pump without two valves. But do not go on thinking of them all the time I am explaining to you. 90 AIR PUMP. Now look at my uncle's air pump. You see this glass/' continued Harry, and he pointed to a large glass bell, which stood over a sort of frame or stand. " Lucy, what do you think is in this glass ?" " Air, I suppose," said Lucy. t( It is full of air, and of nothing else/' said Harry. " The thing to be done is to get all the air that is in the bell out of it. And that is to be done by means of these pumps," continued he, pointing to two tall cylinders of brass, which stood upon the stand with the glass bell ; they commu- nicated at the bottom with a pipe, which opened into the bell. There was a handle, by which, as he told Lucy, she could move the pistons of these pumps up and down. " Just in the way in which the piston moved up and down in the water pump yesterday," said she. " I see, I see ; it is all nearly the same thing, only that this pumps air out, as you said, and the other water. I understand it all perfectly." " Stay, stay, Mrs. Quick-Quick, you do not understand it all perfectly yet. You see only the likenesses, but there are differences which you do not see yet, and cannot, my dear Mrs. Quick- Quick, because it takes a great deal more time to see the differences than to catch the likenesses, Mrs. Quick—" She put her hand upon his mouth before he could repeat the offensive words. AIR PUMP. 91 « Brother, do not call me Mrs. Quick-Quick, and I will be as slow as you please, and I will not tell you of any of the likenesses I see. I will be quite silent, and only nod my head, when I understand ever so perfectly." w Then look at the air pump which is before you," said Harry, " and observe what I do. I am going to move the handle which you see at the top, which will raise up one of the pistons. What is underneath the piston ?" u Nothing," said Lucy at first ; but afterwards she added, * I believe there is a vacuum." "True. And what happens directly?" said Harry. " Air comes in directly to fill it, I suppose," said she. " Where does it come from?" said Harry. " It must come from the bell through this pipe," said Lucy, " which leads from the bell to the bottoms of the pumps." " Then, when that happens, there is less air in the bell than there was before : is not there?" said Harry. " Now move the piston down again, and what happens?" 11 You would press the air that is under the piston back again up the pipe into the bell," said Lucy, " if there is not a valve at the bottom of the pump that shuts against it, and prevents it from going back. But, though I do not see it, I. 92 AIR PUMP. . suppose there is such a valve, because you told me that it was necessary in all pumps." " You suppose rightly, and you remember very well," said Harry. " There is such a valve, and it prevents the air from going back into the bell when I push the piston down. But what becomes of the air ? " " It comes out into the open air through the valve in the piston, I suppose." " Very true. Now 1 will move the handle again, and repeat the operation. I should have told you, that we are assisted in pumpino- by the expansive force of the air." " I do not understand that/' said Lucy. " Yes, you do, my dear, if you will only re- collect the experiments papa showed you with a bladder," said Harry. Ages ago?" said Lucy. Yes, you remember seeing the bladder swell out with the expansive force of the air; and you may recollect that, after blowing in air for some time, when we tried to force in more air we could not; the bladder swelled out so that we could hardly hold its mouth together to tie it." " I remember it," said Lucy. " If we had let go the string," said Harry, ?* and the mouth of the bladder had opened, what would have happened?" ee air tump. 93 " The air would have forced its way out/' said Lucy. " Yes ; air, you know, will expand, and fill every empty place. Now I have pumped out all the air that I can from the bell, and, now that it is as empty as we can make it, we call it a vacuum, though very accurate people would tell you, Lucy, that it is not a perfect vacuum." " It will do for me," said Lucy, " and I think I understand the air pump really now. Is there any other difference between it and the water pump, brother ? You said there was a difference.' " I did say so, and I will explain to you what it is, if you will answer my questions patiently. What was it in the glass water pump that you saw yesterday, that pressed up the water into the vacuum below the piston ?" said Harry. ** It was the outer air ; the weight of the outer air pressing upon the surface of the water that was in the tub, forced the water up into the tube." * True ; the same in all water pumps," said Harry. " But here is no water for it to press upon. How then is this vacuum filled ?" " By the weight or force of the air itself only, I believe," said she. " What air ?" said Harry. " It must be the air in the bell/' said she, " for I see no other. But that is so little that there cannot be weight enough in that." 94 AIR PUMP. " No," said he, " it is not by loeight that this pump acts, but by the springiness of the air itself. This is the difference which I wanted you to observe, between the air pump and water pumps." " By the springiness of the air?" said Lucy. "Yes," said Harry ; "you felt the force- of that springiness in the bladder when it was full of air." Lucy said she should like to feel it again. She had almost forgotten it. Harry blew into a bladder, and filled it with air, and when it was full bid her try to press it together; when she tried to do it she perceived the sort of resistance that it made, and she felt the force with which, after she had squeezed it, it returned to its former place and form. " The same springiness,'' said Harry, " or what is called the elasticity of the air in the bell, is what fills the vacuum below the piston, each time it is drawn up. Now here is the description and plate of the air pump in Scientific Dialogues, and this is all that you need know about it at present. Stay, I will just look at the print of it in Rees's Cyclopedia, and see if I have left out any thing that I ought to tell you." As he opened the book, and as Lucy saw the engravings, she looked a little alarmed. " There seem to be as many different air pumps as hygrometers," said she, sigrhin^. AIR PUMP. 95 « Do not be afraid, I am not going to show them to you all," said Harry ; " but, now that you know the general principle, you would soon feel it easy, as I did, to understand them". " Oh no ! " said Lucy, " there seem to be such a number of pipes and valves, and little as and 6's, and ps and ^'s." u They only relate to the contrivances to prevent the outer air from coming in, while we are pumping the air out of the vessel that is to be emptied, which it is constantly trying to do. One pump is better than another only as it does this most effectually and most easily, and as it more perfectly empties or exhausts the vessel. By the by, I should tell you that, this glass vessel is called a receiver, and when it is emptied it is called an exhausted receive?-. I was puzzled at first by those words, exhausted receiver." " Thank you, Harry, for remembering that for me." u Now, my dear Lucy, you shall work a little at the air pump yourself, as you did at the water pump yesterday.'' * Oh thank you, thank you," said she, joy- fully ; " there is nothing like working oneself; it fixes a thing so well in my memory. I remember the look and touch of the things much better afterwards." While Harry was placing the machine, so that ft (C 96 AIR PUMP. it should be convenient to Lucy, she turned to look at the book of engravings, that lay open on the table. How well this air pump is done," said she. It is very like my uncle's ; not quite, perhaps. I will take care to mind about the differences." " This is very like it," said Harry ; " there is no difference of any consequence." "If we had not had my uncle's," said Lucy, " I think you could have made me understand the air pump quite well from this engraving; that is, after my having seen the glass pump yesterday, and its valve and the piston ; but with- out that I could not have understood it from this representation; because I see here only the out- side of a pump. Even though you had described the valves, and explained them to me ever so clearly, I should not have understood them so well as by having- seen and touched them, and moved them myself." " Certainly," said Harry ; " but, next to seeing the real thing, these engravings or drawings help one very much. Look, though you see only the outside of the pump in that perspective view, here is the inside of an air pump, all laid open for you. You know what is meant by a section?' 1 « Oh ! yes," said Lucy. " Suppose any thing to be cut in two, what you see inside of each part, when they are separated, is a section. Papa AIR PUMP. 97 explained that, and showed it to me, when he cut a lemon in two for me. I remember this minute, as well as if it were before my eyes, the look of the lemon, with the pippins cut in half, each in their little cells, the cells cut open too; and I remember — " " Very well, my dear," interrupted Harry, " you remember very well what is meant by a section, therefore you will understand this plate and this figure. But, Lucy, never be ashamed to tell me if you do not understand; you know I have but just learnt these things myself, and I remember the odd mistakes I used to make, and the puzzles I was in when papa was teaching me." Lucy looked at the engravings now without alarm, because, as she knew what they represented, they did not puzzle her, and she was not afraid of beincr tired. After having looked at the section, she said it made the whole as plain to her eye as if it had been made of glass. Something farther she said to herself, about a mans having a window in his breast ; but either she did not say it loud enough for Harry to hear, or he did not think it much to the purpose, for without attending to it he shut the book, saying, " Now -we have had enough of the prints. I thought just now you were very eager to work the air pump yourself, Lucy." * So I am still," said Lucy ; " only it was not H 98 AIR PUMP. quite ready, and I looked at the prints between times. Now let me pump." " Pump away ; this way," said he, showing her how to hold the handle, and how to move it backwards and forwards, and how she worked two pistons at the same time. She worked it, but not without difficulty. After she had pumped for some minutes, she found the difficulty increasing, and asked from what this arose. Harry said, from the resistance made by the pressure of the outward air, which becomes greater as the receiver is more and more exhausted. He took off the receiver, and put her hand over the hole at the top of the pipe, which communicates with the pumps, and bid her move the pistons with her other hand gently. She did so, and felt that part of the palm of her hand, which was over the pipe, drawn in. Her brother repeated, " gently, gently, 1 ' as she moved the handle. Indeed, soon there was no occasion to say so to her, for she felt the palm drawn in so as to be quite painful, and she grew red with fright. " Oh ! brother, it hurts me very much ; I cannot take my hand away. What shall I do ? " ** Stop pumping," said he, te and do not be frightened ; there is no danger." She stopped pumping, and her brother turned a screw, so as to let in the air. This relieved her air tump. 99 hand. She held it up to show him a purple circle on the inside of her hand. He pitied it a little — a very little. Lucy thought not quite enough. " I know," said he, " exactly how much it hurts you, because I have done the same a hundred times to my own hand. My dear, I wanted you to feel as I did myself. There is, as you said, nothing like feeling, to make one remember well. What do you think caused this ?" At first Lucy answered that she did not know. " Because you are thinking of the pain in your hand," said he. " That is true," said Lucy, fi but it is pretty well over now. What did you ask me?" " I asked you what caused that kind of sucking in of your hand," She thought for an instant, and answered., " I believe it was the pressure of the outer air, which was trying to get in at that hole, to fill the vacuum, and which was prevented by the palm of my hand, which it then drove in as much as it could. Well, now I am sure I have felt ' the pressure of the viewless air;' and now you must let me repeat the line, * The spring and pressure of the viewless air.' " Harry repeated it after her, declaring it was a very pretty line, besides, it had some common sense in it. Lucy had said it quite at the right h2 100 AIR PUMP. time, when it did not interrupt him, or any thin** that was going on. He was so much pleased with it, that he begged of her to repeat all those lines again for him ; and when they went out to their garden soon afterwards, instead of beginning to dig, he desired her to say the lines once more, for that he must learn them by heart, Thus he learnt from her some of her taste for poetry, while she acquired from him some of his love of science. In repeating these lines, Lucy observed which of them alluded to the barometer, and which to the air pump. When she had first learned them by rote, barometer and air pump had been so jumbled in her head, that she could not under- stand them. " How up exhausted tubes bright currents flow Of liquid silver from the lake below ; Weigh the long column of th' incumbent skies, And with the changeful moment fall or rise — " she now knew described the barometer, and the succeeding lines the air pump : " How, as in brazen pumps the pistons move, The membrane valve sustains the weight above ; Stroke follows stroke, the gelid vapour falls, And misty dew-drops dim the crystal walls ; Rare and more rare expands the fluid thin, And silence dwells with vacancy within." While Harry was learning these lines by heart, Lucy stopped as she prompted the couplet con- cerning " gelid vapour" and " misty dew-drops," AIR PUMP. 101 and objected, " I do not understand about misty- dew-drops on the crystal walls. I did not per- ceive any vapour on the glass bell." Her brother told her that these lines alluded to a fact which he had not yet mentioned to her, which his father had but very lately told him, and he was not clear enough yet about it to attempt, to explain it to her. Lucy said she was satisfied to wait ; that it was best not to know every thing at once, and pleasant to have something to look forward to. But altogether she confessed that, though the air pump was curious and ingenious, to use the air to drive itself out, yet the water pump she thought a much grander, and a much more useful machine. She thought the air pump was not of any use. Harry smiled, and answered, " So I thought at first. But, my dear, that was owing to mv ignorance; and when you know more you will find that the air pump is of great use. There are many experiments in natural history, as papa showed me, that could never have been tried, and discoveries that could never have been made, without it. For instance, to give you a little peep into the matter, we could never, without an air pump, have known that a guinea and a feather would fall to the ground in the same time, if there was no air to resist the fall of either of them." 102 AIR PUMP. iC A guinea and a feather ! A heavy guinea and a light feather ! oh, brother !" u Very true, I assure you ; as you will see one of these days." ft Harry, now I think I recollect I heard this about the guinea and the feather before, or read it somewhere ; and something else too about the guinea's making no more noise than the feather when it falls. You will show me this too, will you ?" " I am not sure that T can, Lucy," said Harry. " I tried in this air pump, and I did not find it was so. The guinea fell on the metal plate here at the bottom, and this plate touches the outer air, and rings, and makes a noise." • I do not clearly understand why it should make a noise when it falls, or why it should not," said Lucy. " I cannot explain it yet," said Harry ; ■ and I must try the experiment about the noise over again, to make myself sure whether I am right or wrong. I am certain that the feather and guinea come to the ground in the same time, for that experiment I have tried often, and it always succeeded." " Show it to me now," said Lucy. " No, not now. But you shall see all this, and a great deal more in time," said Harry. " But, Lucy, how could you say that the air pump is of no use ? When you know more about it, you will AIR PUMP. 103 see how much you were mistaken. You will find that all we know about the specific gravities, the different weights of bodies, and a great many curious facts about sound, and I cannot tell you how many delightful experiments and discoveries about the air that comes out of vegetables, and about the growing of seeds and of plants, and other experiments about different kinds of gases, as they are called — I say, my dear Lucy, as my father told me, none of these could have been known without the air pump. And then as to the gases — Oh, my dear, I cannot explain to you yet of what amazing consequence the gases are." Lucy opened her eyes, and stood looking, as if she thought she could never admire enough. After a reverend pause, she simply repeated the word " Gases !" u My dear, do not ask me about them yet. You are a great, great way yet from the gases. But if you are good I will put you into boiling water to-night at tea, and get you on to steam and the steam engine." " Thank you," said Lucy, without knowing clearly w T hat was to happen to her. " Now let us finish the new walk to my garden," said Harry. " But, before we go, I hope you will acknowledge the air pump, besides being very in- genious, is as useful as the water pump at least. Hey, Mrs Lucy, you look as if you were not con- vinced yet." 104 AIR PUMP. " I must wait till I have seen and till I can un- derstand all these things, before I can decide," said Lucy. " Very prove-kingly prudent and slow all at once," muttered Harry, striking the stones of the new road with his pounder. " Why, brother, how can I possibly say more, when you tell me I am so far from the gases ? and I am sure I did not understand a word you said about specific gravities ; as to the experiment about the feather and the guinea, I long to see that, with all my heart ; and I dare say I shall like the others about sound, and seeds, and vegetables, par- ticularly. But these are all curious experiments for grand philosophers, with your air pump ; they may be useful to your men of science, brother ; but what I say is, that the common pump is more use- ful to common people, every day. And I do say, that I like those machines best which are most useful." All the rest Harry heard patiently or passively, as he went on pounding his road ; but when she came to the last words, "And I do say, that I like those machines best which are most useful," he threw down his pounder, exclaiming, " You are very ungrateful, Lucy!" and he wiped his forehead, for he was very hot ; but, checking him- self, he added, " Ungrateful to the air-pump, I mean." AIR PUMP. 105 *' My dear, I did not mean to be ungrateful to the air pump," said Lucy, surprised that he could orow so warm about it. " I did not mean to affront the air pump, or you : I am sure I did not know you cared which I preferred. What can make you care so much about the pumps ?" " I do not know," said Harry. " But I was vexed because you would not do justice to the air pump, and gave your opinion against it, without knowing all, I thought that you were like that foolish woman who said to the great chemist, ' Of what use is all your chemistry, if it cannot teach you to tell me how to take the iron-moulds out of my gown?' Lucy, I hope you will never be so foolish." " Never, I hope," said Lucy ; rf and 1 hope you do not think I ever shall." " No, I hope not," said Harry. " But now I must say for the air pump, there is a use that may be made of it in common every day, in hot weather, to make something that is exceedingly agreeable." " What can it be ?" said Lucy. " Particularly with sweet-meats and creams," continued Harry. " Very good of pine-apple and pleasant of tea ; mamma told me, not bad even of water." " Do you mean ice ?" said Lucy. " Yes,'' said he, * the air pump can make ice." "Oh! Harry, I cannot believe that. How car that po&sibly be done ?" 106 AIR PUMP. " Go to • Conversations on Chemistry/ my dear, and you will be answered." " Very well, I will go to ' Conversations on Che- mistry,' " said Lucy : fl but not till I have dug this bed in my garden, and tied up all my carnations, and fed my white rabbit, and finished drawing the last snake of my head of Medusa, and put by the sulphurs in the cabinet, and practised e The Rising of the Lark.' " "Very little chance indeed, through all that jumble of things, of your remembering Conversa- tions on Chemistry and the air pump," said Harry " You shall see," said Lucy ; (c I have always a good memory for what I wish to do." 107 MAKING ICE. u Harry, I have done all that I said I would : I have dug the bed in my garden, tied up my car- nations, fed my white rabbit, finished my Medusa's snakes, put the sulphurs into their cabinet, prac- tised my ' Rising of the Lark,' and read and under- stood all that you marked for me in ( Conversa- tions on Chemistry*.' * " Really ! you have done a great deal," said Harry ; " much more than I expected. I thought the white rabbit would have made you forget every thing else. And do you quite understand all you have read ?" " I do," said Lucy, " for it is very clear. As I was reading I thought I saw every thing that was described ; and, after I had finished, I was more anxious than before to see the experiment you pro- mised to show me. Will von let me see it now, before I forget what I understand, and while my head is in it, as you say T* " I will show it to you as soon as ever I can," said Harry, "with my father's assistance. He says that I must not attempt to try this experi- * Eighth edition, vol. i., from page 151 to 160. 108 MAKING ICE. ment by ourselves, because sulphuric acid, which must be used in it, is very dangerous to meddle with. If we dropped any of it on our clothes, it would burn holes in them ; and, if we were to let a drop fall on ourselves, it would hurt us exceed- ingly, So take care, Lucy, not to meddle with it." ■_' I will take great care/' said Lucy. M I will look, but not touch." While Harry went out of the room to his father, who was preparing for their experiment, Lucy talked to her mother about the entertaining ac- count, which she had just been reading, of the method of making ice in India, even in the hottest nights. " How glad they must be, mamma," said Lucy, "when in the morning they see the ice in the shallow pans, which they leave out of doors during the night! Mamma," continued she, "I think that the Emily and Caroline in this book must have been very happy, seeing all the nice experi- ments mentioned here, and talking to their mother about them, and learning from her. This Mrs. B. seems to be a very good, kind mother. I should like to know her, if she is really a live person. Is there such a real person as Mrs. B., mamma?" " Yes, there is, Lucy." " There is ! And are you acquainted with her, mamma?" Lucy asked eagerly. " I am, my dear." (I « MAKING ICE. 109 e i You are ! And what sort of a person is she ? Do you like her ? Oh ! yes, mamma, I see by your look before you speak. You like her very much." I do, indeed, Lucy."' I am glad she is an acquaintance of yours, mamma. I hope I shall see her some time." " She is more than an acquaintance of mine, she is my friend ; and if you deserve it, my dear daugh- ter, I hope that she will some time be yours." " Oh, brother ! What do you think mamma has just told me ?" cried Lucy, running to meet Harry, who at this instant opened the door, and came in, followed by his father. " Oh, papa, do you know — " But observing that her father's hands were full, and that he and Harry were intent upon brinaino- in the air pump, she "wisely ceased her exclama- tions, and stopped short in what she was going to say. " Right to be silent, my dear,'' said her father, as she stood by without uttering a word, all the time they were preparing to show her the ex- periment. " It is very troublesome and disagree- able to have little girls, or little anybodies, or great anybodies, talking all the time we are busy pre- paring experiments." " Busy and anxious too, you know, papa ; for some experiments are dangerous," said Harry. 110 MAKING ICE. Lucy had learned, from what she had just read, that sudden evaporation can be caused by taking the pressure of the atmosphere off water, which produces cold sufficient to freeze it even when the outer air is much above the freezing point. A thermometer was near the air pump, and Lucy looked at it, as Harry desired she would. She saw that the mercury stood at 65 degrees, and she felt that the room was warm. Her father placed under the receiver a large shallow saucer, filled with sulphuric acid, and in it a small cup of water, raised on a little stand, with a thermometer in it, as described in " Con- versations on Chemistry." He asked Lucy if she knew for what purpose the sulphuric acid was put there. She said that the book had told her, that the use of the sulphuric acid was- to attract and absorb the water as it was evaporated. " And why should it be absorbed ?" said her father. " Because we want to freeze the water," said Lucy. "True; but you have not explained to me why we desire that the sulphuric acid should absorb this vapour." " Because, papa, that vapour fills up part of the vacuum, and it must be taken away, and the sul- phuric acid does this as it absorbs it." MAKING ICE. Ill " She understands it," said Harry. " Now we may go on — look, Lucy, at what haopens — keep your eyes fixed upon the water." She did so, and she soon saw little bubbles appearing on its surface. It is beginning to do something,'' said she ; but it looks more as if it were going to boil than to freeze." M You know," said he, " that before water can freeze it must appear to boil." "Yes, appear ; I understand why you say ap- pear. That was explained to me in the book." " Now it begins to freeze," said Harry, " look at the little spikes of ice." Lucy saw this, and said it was very curious ; but still she did not look quite so much surprised and pleased as Harry had expected, because, as she said, she saw only such tiny spikes of ice. She had imagined that all the remaining water in the cup would have been turned at once into a solid lump. Harry had talked to her about pine apple ice, and various other kinds of ice, which were so plea- sant to eat in hot weather, and which he boasted that the air pump was so useful in assisting people to make ; but, from the tiny spikes she had seen, she could scarcely conceive that a sufficient quantity could be made for this good purpose. Harry asked his mother if she would give them some cream 112 MAKING ICE. and some sweetmeat to make sweet ice cream ; tie wished exceedingly to show Lucy that it could really be done in the air pump. Their kind mother provided them with all that Harry desired ; but she doubted that they would be able to succeed, as it was difficult even to freeze water. Harry was deter- mined to try, for he had heard that it was a com- mon practice in London, to make use of an air pump in making ice cream. His father warned him that he was mistaken, but that he might try, and that he would then find out what his mistake had been. Harry put the cream into a small tea cup, and Lucy mixed with it their raspberry jelly. They put the tea cup into a larger cup filled with water, and this they placed on a little stand, which rested on a saucer, filled with sulphuric acid, within the glass bell of the air pump. It happened, as it too often happens to young experimenters, and to old ones also, that their experiment did not succeed. They could not freeze the cream. They tried to console themselves by eating the cream and sweetmeat. This was, however, but an imperfect consolation to Harry. The honour of the air pump and his own were at stake, and he recurred to the subject immediately. " I suppose my mistake was in putting the cream and sweetmeat into the air pump. I was only told that the air pump was useful in making ice. How MAKING ICE. 113 they make the ice cream with it I cannot guess," said Harry. " I can tell you that," said Lucy, " for I once saw the housekeeper make raspberry ice-cream." " Have you ?" said Harry ; " and how did she do it r 11 She put some cream and sweetmeat into a tin cylinder : tin I believe it was, or pewter. And this she surrounded with a great deal of pounded ice and salt. Then she kept turning and turning the cylinder round, with the cream in it, till at last it was all frozen." " Oh ! oh !" said Harry, " then now I see how it is. The air pump produces ice enough to freeze the cream. That must be the way it is useful." " But how can it produce it in such quantities as would be necessary ? It would be a year at the rate I saw it going on, with a little cup full of water," said Lucy. Harry acknowledged this, and they appealed to their father. He told them, that, for this purpose, much larger air pumps than they had ever seen would be necessary. That consequently a greater va- cuum was produced, and more water frozen. a Then it is true; Lucy, you see, the air pump does make the ice that makes the ice cream, and it is used for this purpose in London. Is not it, papa : 114 MAKING ICE. " Not in London/' answered their father ; " it is too expensive a process to be of much advantage in this country ; but I believe it has been found useful in India." u In India ! There, Lucy, you see how useful it is, and how far its fame goes/' said Harry. i( Did they really send an air pump made in England to India for this purpose ?" M Yes," said her father. * And, when we go to London, I will show you Mr. Carey's apparatus for making ice." " Oh ! thank you, father ; and I shall really see it made, not in little spikes, but in quantities," said Lucy. "Now, Lucy, you will acknowledge," said Harry, ee that the air pump is useful for common purposes." "I will ; I do," said Lucy. " And you will have much more to acknowledge on this subject by and by," said her father ; " when you see that it is applied to other purposes of common life." " Oh ! what, father?" cried Harry. "That I will not tell you now, Harry. 115 STEAM-ENGINE, In the evening, before tea-time, Harry and Lucy played at spiilikens, and afterwards a game of chess, in which Harry was beaten; because he was thinking of something he was going to tell Lucy about the steam-engine, and he missed seeing a rogue of a knight that had got so close to his king, that he could not stir without being check-mated. "Now for the steam-engine, which you pro- mised to explain to me," said Lucy. Harry was afraid that he could not, and, turning to his father, asked him to explain it. But his father desired that he would first try what he could do "This will be of service to you, Harry, for you will be then certain whether you comprehend it yourself or not. People are never sure they un- derstand anything perfectly till they have ex- plained it to another. If Lucy is puzzled I will help you out of your difficulty, whatever it may be." Harry said he would try, and began with these words :— i i 2 116 STEAM-ENGINE. " In the first place, a steam-engine is a machine — " There he stopped, and began again with, " In the first place, Lucy, you must know, that the machine called the steam-engine was invented — " He stopped short again, and a third time he attempted it, but he hesitated, and blushed, and, turning again to his father, lie said, " I can- not explain it before you, father. I am so anxious. It is very odd. I am not the least afraid of you, you know ; but I feel so ashamed and anxious. I think I should do it a great deal better if you were not by." ',' Very well," said his father, laughing ; i( then either you or I must go out of the room it seems. Luckily for you, I am just going into the next room. Is that far enough off'? though the folding doors are open, I assure you I shall not hear you," <( That will do perfectly," said Harry. " But what will you do about mamma ! She must stay to make tea," said Lucy. " Look, here is the urn coming in. Had not you better come out into the hall with me, Harry ?" " No, no," said Harry, " I do not mind mamma ; and, now I think of it, I want the urn. Lucy, look at the steam coming from the top of that urn; do you recollect, a great while ago, my father's holding a cold plate over the steam coming from the urn ?" STEAM-ENGINE. 117 "Yes," Lucy said, she remembered it well, though it was a great while ago. She remem- bered that the cold of the plate had turned the steam into water again, — had condensed it. She recollected the drops on the plate, which after- wards ran into each other, and down into little streams, when the plate was sloped. u Yes," interrupted Harry, " you have recol- lected enough of that; you are clear then that cold can condense steam, that is, can turn it back ag"ain into water." " Perfectly clear," said Lucy. " Now recollect another thing," said Harry ; e( which took up most room, the steam when it was steam, or when it was turned into water ?" " It took up much the most room when it was steam," said Lucy. "I am sure that cloud of steam which you see rising from the tea-urn, and which takes up so much room in the air, might, if vou held a cold plate over it this minute, be condensed into a few: drops, which would not half fill a tea-spoon." " Very true," said Harry ; " now do not think any more about that; but do you recollect our talking, a great while ago, about the tea-kettle's boiling over, as it is called? and do you remem- ber my saying, that if the top of the tea-kettle was screwed down tight, and if the spout was stopped, 118 STEAM-ENGINE. so that no steam could get out, that I thought the tea-kettle would burst ?" "I remember it all," said Lucy; "and papa said, you were very right ; and I remember after- wards the bursting and explosion of my chestnuts ; and the story papa told us of his pouring the hot lead into the damp elder, to make a pencil ; and the fact* I read about the bursting of a little hollow brass ball, in which there was water that turned to steam, and which caused an explosion, that blew a whole foundry to pieces." " Then you have some idea of the power of the expansion of steam," said Harry. "To be sure I have," said Lucy; " I know it is terribly great, bursting and killing people, and tearing away! How frightened I should have been, if I had been papa, when he was a little boy, when the lead bounced up to the top of the ceiling ! I am sure I was frightened enough when my own horse chestnuts bounced." But if this terribly great power," said Harry, were carefully used, and cleverly used, it would do, as you shall see, the most surprising and the most useful things ; it would raise water high as the house, and higher, from the bottom of the deepest mine : it could raise the weight of this room, and all that is in it, as high as the top of the highest tree, and higher." * Scientific Dialogues. ti ce STEAM-ENGINE. 119 " Oh, brother ! brother !" cried Lucy. "It is quite true ; it can do more in an hour than two hundred horses and fourteen hundred men. It can drag loaded waggons full of coal, such as you have seen going step by step, the horses pulling hard — it can pull these waggons up as easily as I can pull your little cart." " My dear brother, how can I believe it?" said Lucy. " It can drive across the sea, against the power of the wind and the tide, a great ship, with all the people in it, and all their horses and carriages, and all that they have in the world." i( Is it really possible ?" said Lucy. " I have heard people talking of steam-boats, and of the working of steam-engines ; and I remember papa's asking a gentleman, who was here the other day, whether his steam-engine was an hundred horse power. But I never knew how this was, nor could I conceive that steam could do all this by itself. Only steam like that ?" said she, fixing her eyes upon the steam that still came from the tea- urn. " Yes, only steam like that," repeated Harry. "Think what we men can make it do at our bidding." " Really and truly, Harry," said Lucy, rt it does more at men's bidding than any of the genii in the Arabian Tales, more than any of the slaves of 120 STEAM-ENGINE. Aladdin's lamp, for the hardest working of them could only be made to carry one house."