Glimpses of nature beauty ART

download

of 268

  • date post

    09-Sep-2014
  • Category

    Education
  • view

    791
  • download

    15

Embed Size (px)

description

Glimpses of nature beauty ART

transcript

  • UC-NRLFSM E72

THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA PRESENTED BYPROF. CHARLES A. KOFOID AND MRS. PRUDENCE W. KOFOID GLIMPSESNATURAL HISTORY. BERLIN W. FRONTISPIECE. GHMPSES ^NAT iTfWhat prodigies can Power Divine perform,More grand than it produces year by year,And all in sight of inattentive man ! COWPER LONDON :HARVEY AND DARTON, GRACECHURCH-STREET. LO.VDONJOSEPH RJCKERBY, PRINTER,SHBRBOURN-LANK. Hfc PREFACE.THE intention of this simplelittle Work is so obvious,that itperhaps scarcely requires a preface. Written todirect theattention of one much-loved child to thegoodness and power of God, as displayed in all histvorks, it isnow offered to many, in the hope that from"these Glimpses of Natural History" theymay beledto more extended views of so boundless asubject. LONDON, 1843.M348387 CONTENTS....... .......The Walrus and FlyGalls Page.19SnailsThe Camel....... . . . . . . ..16 26Charcoal .......The Sunflower. . ....3540Sponge .........Rust Indian-rubber . . Lead . Pencils, &c. . . ..4658Colours ..........A Traveller...6773Rain ............Fall of the Leaf .8087On ...... Rooks, &c.Insect ChangesVariety in Nature. . . . . .96 104.115Water-Pimpernel. . . . . .125 vi CONTENTS. Page.Evergreens1 K/Leaf-insects .158MossesHorsetail.Heaths, &c,.Mother-of-l>earl THE WALRUS.Page 1. GLIMPSES OF NATURAL HISTORY.THE WALRUS ANDFLY.AUNT.Do yourecollect the description I read to you theother morning of that icy region, Spitzbergen, and ofthe animals which inhabitit ?MARY.Oh, yes, perfectly.AUNT.Then youperhaps, be able to answer the ques- will,tion I amgoing to ask you.What resemblance isthere between a walrus and a fly ?MARY.Really, my dear aunt, you are proposing an enigmaB 2THE WALRUS AND FLY.tome. HowcanI discover any likeness between thatlarge, inactive, disgusting creature, and the little alertinsect I often watch with somuch pleasure ? AUNT.Ido not refer to their appearance, for in that thereis, indeed, no similarity. But consider what I toldyou of the habits of the walrus of its manner of moving, ;for example.Are you not now struck with any pointof resemblance ? MARY.I remember youtold me the walrus can climb per-pendicular masses of ice,and I see flies ascending ourglass windows, and I should think their surfacesome-thing like that of the smooth, polished ice, so perhaps Ihave found out your enigma. AUNT.You have.I did not, however, propose it merely to tryyour ingenuity, but in order that I may give you anexplanation of the means by which both these creaturesare able to surmount the law by which the motions of THE WALRUS ANDFLY.3all others (with very few exceptions) are guided, andthus to sustain their bodies against gravity.Beforeattempting this I must recal to your mind a subject Ialluded to in our reading yesterday, and which I pro-mised to recur to : the pressure of the atmosphere. MARY.Oh ! I have been wishing for some explanation ofthat term, for I cannot understand how it can be appliedto a fluid, asyou have told me the air is so thin andtransparent, that though we are surrounded by it we canneither feel nor see it. AUNT.Our being surrounded by it is the very reason whywe do not feel it. Our bodiesare so equally supportedbyit on all sides, that we do not perceive any partialpressure; but if I could remove the portion of air fromone side ofbody, the weight and consequent pres-mysure would be so great that I should no longer be ableto bearit.And this is proved by a machine called anair-pump, bywhich a vessel may be deprived of the airit contains, and a vacuum formed. A familiar instance B -2 4 THE WALRUS AND FLY.will serve toshow how, by thismeans, we discover thepressure of air. If you were to put any body, yourhand, for instance, over a jar with an opening at bothends on an air-pump, as the pump was worked youwould find a gradually increasing weight on your hand,and at length, when the operation was completed, andthe air in the jar quite exhausted, you would find itimpossible, by any exertion of force, to lift your handfrom thejar. MARY.Then, I suppose, the air above the hand presses itdown, and it cannot be raised because there is no airbelow tooffer resistance. AUNT.Exactly so;for when air is pumpedin again thehand is raised with the greatest ease.But now for theapplication of what I have said to our present subject,which, I fear, this long digression will almost have madeyou forget. MARY.No, indeed; you said that afly and a walrus haveboth the power of walking againstgravity. THE WALRUS AND FLY. 5AUNT.Very well :now, the reason of their possessing thispower is, that they are furnished with an apparatus bywhich they can form a vacuum, and adhere to the verti-cal glass or iceby atmospheric pressure. The air isexpelled from the space below their feet, and the weightof the air above their feet causes them to adhere ; but, atthe same time, they are wisely provided with muscularforce sufficient to raise their feet with the greatest ease,so that theirmovements arenot impeded. If youremark the flies which congregate in our houses in theautumn, you will see that they are at first very livelyand active, but that as they grow torpid they move withdifficulty, as iffastened to the window. When they arewell and active theyeasily overcome the atmosphericpressure, but as the weather becomes colder, it makesthem sickly and weak, and then this resistance is toogreat an effort for their declining strength, and you mayseethem toiling along, as if their feet were too heavy forthem, nay, sometimes even sticking to the glass till theydie.MARY. Whofirst discovered that flies had this singular power ? 6THE WALRUS AND FLY. AUNT.It is to Sir Everard Homethat we are indebted forascertaining the fact.had been suspected by former Itnaturalists, but he proved it by examination. For sometime he was in doubt about two points with which theis provided, not being able to understandfoot of the flyfor what purpose they were there. It had been imaginedthat they were inserted in the cavities of the surfaceover which the insect was walking, and thus retained itin opposition to gravity ;in this opinion, however, SirEverardHomedid not agree. On examining the footof the walrus he discovered their use there it was :evident that two toes (which answer to the points in theflys foot) are used for the purpose of bringing the webclosely down upon the surface traversed, so as to enablethe animal to form a more complete vacuum, and thatthe ah* is readmitted on their being lifted up. MARY.What a difference there must be in size between thetwo feet ! AUNT.Yes, that of the fly requiresmagnifying one hundred THE WALRUSAND FLY.7times to makethe apparatus i have described visible,while that of the walrus must be diminished four timesto bring it within the compass of a quarto plate.MARY. Thank you, my dear aunt, for your, explanation I:shall now never see flies on our windows without recol-lecting it, and I shall observe them more closely.AUNT.There are otherfamiliar instances inwhich you mayremark thispower of the atmosphere.You rememberthe difficulty we found the other morning in detachingthe limpets you wished from the rock to which theywere so firmly fixed ; if you examine them you will findthat they have no apparent means adequate to resist theforce you applied to them. The edge of the shell isnot furnished with any mechanism by which to hold thesubstance on which it is placed this is, indeed, so hard;and smooth, that it would be difficult to conceive anythat would answer the purpose.It is retained initssituation by the formation of a vacuum below the shell,and the consequent pressure of the air on its outer sur- 8 THE WALRUS ANDFLY.face.Sea-anemonies, again, are attached by the samemeans they are such soft, gelatinous bodies, that it :seems as ifone had only to put ones hand to the rockto gain possession ofthem but we find a strong resist- ;ance.You musthave remarked that when you touchan anemone itimmediately shrinks by this movement ;it is, no doubt, putting itself on the defensive, andexpelling the air from between it and the rock.Snails,periwinkles, &c. &c. adhere by the same means.Inthe same situations as limpets and periwinkles you willfind, very frequently, clusters of muscles, which are alsoattached to the rocks, but here observe a difference inthe manner : the form of the muscle does not admit ofits forming a vacuum, but it has a beautiful provision ofits own ; it has the power of throwing out a cluster ofsilky filaments, which fix themselves to the rock, andby whichit hangs securely. GALLS. MARY.HEREone of those curious mossy tufts on this rose*isbranch which I have often thought of asking you about.They are very pretty, but yet one only sees them occa-sionally, therefore, I suppose, they are not a usual pro-duction of the rose-tree.Perhaps you can tell mesomething of them.AUNT. I am not surprised at your feeling curious respectingthese singular excrescences, and you will be astonished,I think, when I tell you what purpose theyserve. Theyare the habitations of insects. MARY.The habitations of insects ! you really do surprise me.But how can that be, for I can see no opening ;not one 10GALLS.sufficient even for a very tiny insect to have entered by,and I should imagine, from the size of the tuft, that itsoccupant is not so diminutive, unless its house be verymuchtoo large for it.AUNT.Your wonder is very natural, for it has perplexed manywiser persons to account for the bodies called galls, andwhich originate from the same cause as the moss-likeappearance we are speakingof. Theancient philoso-phers, finding on opening these substances that theycontained grubs, conceived justly that these proceededfrom eggs, but they were embarrassed by the same cir-cumstance that perplexes you. They were at a loss toaccount for the conveyance of these eggs into themiddle of a substance in which they could find noexternal orifice.They imagined that they were theeggs of insects deposited in the ear