i Presented to the LIBRARY of the UNIVERSITY OF TORONTO by SHARON & KEN DINT - I r- 1 HISTORY OF THE EARTH AND ANIMATED NATURE. BY OLIVER GOLDSMITH. WITH COPIOUS NOTES; ^nd an ^ppenOix, CONTAINING EXPLANATIONS OF TECHNICAL TERMS, AND AN OUTLINE OF THE CUVIEUIAN AM) OTHER SYSTEMS, BY CAPTAIN THOMAS BROWN, F.L.S., M.W.S., M.K.S. . VOL. I.-PART I. A. FULLARTON AND CO., EDINBURGH, GLASGOW, AND LONDON. 1840. GLASGOW: PULLARTON AVU CO., PBINTKRS, VJLLtFIELO. I '■^ ■J^'^ *, '^'•Ur ^>^^. ^^— ^ '■1 hy /LFuUartoiv I- Co. GUl^ov. AN© AMIMA'T]!]!) MiklTUMH BY OLIVER OOJLD SMITH. VX'^lTH COPIOUS NOTES. TO WHirU IS SUBJOXJfED ASf ATTmm3K:K. / C'AFT-T Tif'{J)MAS ER©W^, JF.JL.S. M.W:.^_MJK.S. rRESlDENT OF XHE KOYAi PHTSICAL SOCIETY ''"■>«'.<:•■..« YOLA. AKTHliBAILD Ff^LLA'RTOy X- ViS). A HISTORY OF THE EAllTH AND ANIMATED NATURE. BY OLIVER GOLDSMITH. WITH COPIOUS NOTES; •slnD an StppenUix, CONTAINING EXPI-ANATIONS OF TECHNICAL TERMS, AND AN OUTLINE OP TUB ClIVIERIAN AND OTHER SYSTEMS, BY CAPTAIN THOMAS BROWN, F.L.S., M.W.S., M.K.S. VOL. I. A. FULLARTON AND CO., EDINBURGH, GLASGOW, AND LONDON. 1840. x'?^^A"k'p vj ril.ASCOW: "ULLAnrDN AXUCO., i'KINTCliS, V ILl. \ !■ I Ki.n. CONTENTS OF VOLUME FIRST. PART I. Chap. I. — A sketch of the Universe, 1. Chap. II. — A short survey of the Globe, from the light of Astronomy nnd Geography, 11. Chap. III. — A view of the Surface of the Earth, 14. Chap. IV. — A Review of the different theories of the Earth, 17. Chap, V. — Of Fossil Shells, and other extraneous Fossils, 28. Chap. VL— Of the Internal Structure of the Earth, 4-1. Chap. VII. — Of Caves, and Subterraneous passages that sink, but not perpendicularly into the Earth, 47. Chap. Vlll. — Of Mines, Damps, and Mmeral Vapours, .55. Chap. IX. — Of Volcanoes and Earthquakes, 66. Chap. X. — Of Earthquakes, 78. Chap. XL — Of the Appearance of New Islands and Tracts : and of the Disappearing of others, 92. Chap. XII.— Of Mountains, 99. Chap. XIII.— Of Water, 116. Chap. XfV.— Of the Origin of Rivers, 137. Chap. XV. — Of the Ocean in general; and of its Salt- ness, 161. Chap. XVI. — Of the Tides Motion, and Currents of the Sea ; with their effects, 173. Chap. XVII. Of the Changes produced by the Sea upon the Earth, 184. (^HAF. XVIII — A summary account of the Mechanical Pro- perties of Air, 199. Chap. XIX. — An Essay towards a Natural History of tlie Air, 207. Chap. XX. — Of Winds, regular and iiregular, 227, Chap. XXI. — Of Meteors and such appearances as result from a combination of the Elements, 250. Chap XXII.— The Conclusion, 270. i V CONTENTS. PART II. OF ANIMALS. Chap. I. — A Comparison of Animals with the inferior ranks of Creation, 274. Chap. II. — Of the Generation of Animals, 281. Chap. III.— The Infancy of Man, 300. Chap. IV.— Of Puberty, 309. Chap. V.— Of the Age of Manhood, 31'1. Chap. VI.— Of Sleep and Hunger, 337. Chap. VII.— Of Seeing, 349. Chap. VIIL— Of Hearing, 358. Chap. IX.— Of Smelling, Feeling, and Tasting, 367. Chap. X Of Old Age and Death, 378. Chap. XI. — Of the Varieties of the Human Race, 387, Chap. XII.— Of Monsters, 413. Chap. XIII.— Of Mummies, Wax-work, &e. 427. Chap. XIV Of Animals, 438. Chap. XV. — Of Quadrupeds in General, compared to Man, 449. A HISTORY OF ANIMALS. BOOK I. — ANIMALS OF THE HORSE KIND. Chap. L— Of the Horse, 466. Chap. IL— Of the Ass, 497. Chap. IIL— Of the Zebra, 509. BOOK II. — OF RUMINATING ANIMAf.S. Chap. I Introduction, 517. Chap. II.— Of Quadrupeds of the Cow kind, 520— the Buf- falo, 541. rUEFACE TO THE ORIGINAL ED1TI6n. Natural History, considered in its utmost extent, comprehends two objects. First, that of discovering, ascertaining, and nam- ing, all the various productions of Nature. Secondly, that of de- scribing the properties, manners, and relations, which they bear to us, and to each other. The first, which is tlie most difficult part of this science, is systematical, dry, mechanical, and incom- plete. The second is more amusing, exhibits new pictures to the imagination, and improves our relish for existence, by widening the prospect of nature around us. iioth, however, are necessary to those who would understand this pleasing science in its utmost extent. The first care of every inquirer, no doubt, should be, to see, to visit, and examine, every object, before he pretends to inspect its habitudes or its history. From seeing and observing the thing itself, be is most naturally led to speculate upon its uses, its delights, or its inconveniences. Numberless obstructions, however, are found in this part of his pursuit that frustrate his diligence and retard his curiosity. The objects in nature are so many, and even those of the same kind are exhibited in such a variety of forms, that the inquirer finds himself lost in the exuberance before him, and, like a man who attempts to count the stars, unassisted by art, his powers are all distracted in barren superfluity. To remedy this embarrassment, artificial systems have been de- vised, which, grouping into masses those parts of nature uioie nearly resembling each other, refer the inquirer for the name of the single object he desires to know, to some one of those general distributions, where it is to be found by farther examination. If, for instance, a man should, in his walks, meet with an ani- mal, the name, and consequently the history, of which he desires to know, he is taught by systematic writers of natural history to examine its most obvious qualities, whether a quadruped, a bird, a fish, or an insect. Having determined 't, for explanation' sake, to be an insect, he examines whether it has wings; if he finds i1 possessed of these, he is taught to examine whether it has two ot vi PREFACE TO THE ORIGINAL EDITION. four ; if possessed of four, he is taught to observe, whether the two upper wings are of a shelly hardness, and serve as cases to those under them ; if he finds the wings composed in this manner, he is then taught to pronounce, that this insect is one of the beetle kind: of the beetle kind, there are three diflFerent classes, distin- guished from each other by their feelers ; he examines the insect before him, and finds that the feelers are clavated or knobbed at the ends ; of beetles, with feelers thus formed, there are ten kinds ; and among those he is taught to look for the precise name of that which is before him. If, for instance, the knob be divided at the ends, and the belly be streaked with white, it is no other than the Don', or the May-bug; an animal, the noxious qualities of which give it a very distinguished rank in the history of the in- sect creation. In this manner a system of natural history may, in some measure, be compared to a dictionary of words. Both are solely intended to explain the names of things ; but with this difference, that in the dictionary of words we are led fi'om the name of the thing to its definition ; whereas in the system of na- tural history, we are led from the definition to find out the name. Such are the efforts of writers, who have composed their works with great labour and ingenuity, to direct the learner in his pro- gress through nature, and to inform him of the name of every animal, plant, or fossil substance, that he happens to meet with : but it would be only deceiving the reader to conceal the truth, which is, that books alone can never teach him this art in perfec- tion : and the solitary student can never succeed. Without a master, and a previous knowledge of many of the objects of na- ture, his book will only serve to confound and disgust him. Few of the individual plants or animals, that he may happen to meet with, are in that precise state of health, or that exact period of vegetation, from whence their descriptions were taken. Perhaps he meets the plant only with leaves, but the systematic writtr has described it in flower. Perhaps he meets the bird before it has moulted its first feathers, while the systematic description was made in its state of full perfection. He thus ranges without an instructor, confused, and with sickening curiosity, from subject to sul)ject, till at last he gives up the pursuit, in the multiplicity of his disappointments. Some practice, therefore, much instruction, and diligent reading, are requisite to make a ready and expert naturalist, who shall be able, even by the help of a system, to find out the name of every object he meets with. But when this tedious, thougli requisite, pait of study 13 attained, nothing but delight and variety attend PREFACE TO THE ORIGINAL EDITION. vH the rest of his jouruey. Wherever he travels, like a man in a counti'y vehere he has many friends, he meets with nothing but acquaintances and allurements in all the stages of his way. The mere uninformed spectator passes on in gloomy solitude ; hut the naturalist, in every plant, in every insect, and every pebble, finds something to entertain his curiosity, and excite his speculation. From hence it appears, that a system may be considered as a dictionary in the study of nature. The ancients, however, who have written most delightfully on this subject, seem entirely to have rejected those humble and mechanical helps to science. They contented themselves with seizing upon the great outlines of history, and passing over what was common, as not worth the de- tail ; they only dwelt upon what was new, great, and surprising, and sometimes even warmed the imagination at the expense of truth. Such of the moderns as revived this science in Europe, undertook the task more methodically, though not in a manner so pleasing. Aldrovandus, Gesner, and Johnson, seemed desirous of uniting the entertaining and rich descriptions of the ancients, with the dry and systematic arrangement, of which they were the first projectors. This attempt, however, was extremely imper- fect, as the great variety of nature was, as j'et, but very inade- quately known. Nevertheless, by attempting to can-y on both objects at once, first directing us to the name of a thing, and then giving the detail of its history, they drew out their woiks into a tedious and unreasonable length ; and thus mixing incompatible aims, they have left their labours rather to be occasionally con- sulted, than read with delight, by posterity. The later moderns, with that good sense which they have car- ried into every other part of science, have taken a different me- thod in cultivating natural history. They have been content to give, not only the brevity, but also the dry and disgusting air of a dictionary, to their systems. Ray, Klein, Brisson, and Lin- naeus, have had only one aim, that of pointing out the object in nature, of discovering its name, and where it was to be found In those authors that treated of it in a more prolix and satisfactory maimer. Thus natural history, at present, is carried on in two distinct and separate channels, the one serving to lead us to the thing, the other conveying the history of the thing, as supposing it already known. The following Natural History is written with only such an attention to system as serves to remove the reader's embarrass- ments, and alluie him to proceed. It can make no pretensioiis in directing him to the name of every object he meets with ; that Vin PREFACE TO THE ORIGINAL EDITION, belongs to works of a different kind, and written with very different aims. It will fully answer my design, if the reader, being already possessed of the name of any animal, shall find here a short, though satisfactory, history of its habitudefs, its subsis- tence, its manners, its friendships, and hostilities. My aim has been to carry on just as much method as was sufficient to shorten my descriptions by generalizing them, and never to follow order where the art of writing, which is but another nfime for good sense, informed me that it would only contribute to the reader's embarrassment. Still, however, the reader will perceive that I have formed a kind of system in the history of every part of animated nature, directing myself by the great obvious distinctions that she herself seems to have made ; which, though too few to point exactly to the name, are yet sufficient to illuminate the subject, and remove the reader's perplexity. INIr Buffon, indeed, who has brought greater talents to this part of learning than any other man, has almost entirely rejected method in classing quadrupeds. This, with great deference to such a character, appears to me running into the opposite extreme ; and as some moderns have of late spent much time, great pains, and some learning, all to very little pur- pose, in systematic arrangement, he seems so much disgusted by their trifling but ostentatious efforts, that he describes the ani- mals almost in the order they happen to come before him. This want of method seems to be a fault ; but he can lose little by a criticism which every dull man can make, or by an error in ar- rangement, from which the dullest are most usually free. In other respects, as far as this able philosopher has gone, 1 have taken him for my guide. The warmth of his style, and the brilliancy of his imagination, are inimitable. I^eaving him, there- fore, without a rival in these, and only availing myself of his in- formation, I have been content to describe things in my own w;iy; and though many of the materials are taken from him, j'et I have added, retrenched, and altered, as I thought proper. It was my intention at one time, whenever 1 differed from him, to have mentioned it at the bottom of the page ; but this occurred so of ten, that I soon found it would look like envy, and might perhaps convict me of those very errors which I was wanting to lay upon him. 1 have, therefore, as being every way his debtor, concealed my dissent, where my opinion was different ; but wherever I borrow from him, 1 take care at the bottom of the page to ex- press my obligations. 13ut though my obligiitions to this writer are many, tbey extend to but the smallest part of the work, as he PREFACE TO THE ORIGINAL EDITION, IX lias hitherto completed only the history of quadrupeds. I was, therefore, left to )ny own reading alone, to make out the history of bix'ds, tishes, and insects, of w^hich the arrangement was so dif- ficult, and the necessary information so widely diffused, and so obscurely related when found, that it proved by much the most laborious part of the undertaking. Thus having made use of Mr Buffon's lights in the first part of the work, I may with some share of confidence recommend it to the public. But what shall 1 say to that part, where 1 have been entirely left without his as- sistance ? As I would affect neither modesty nor confidence, it will be sufiicient to say, that my reading upon this part of the subject has been very extensive; and that 1 have taxed my scanty circumstances in procuring books, which are on this subject, of all others, the most expensive. In consequence of this industry, I here offer a work to the public, of a kind which has never been attempted in ours, or any other modern language, that I know of. The ancients, indeed, and Pliny in particular, have anticipated me in the present manner of treating natural history. Like those historians who describe the events of a campaign, they have not condescended to give the private particulars of every individual that formed the army ; they were content with characterizing the generals, and describing their operations, while they left it to meaner hands' to carry the muster-roll. I have followed their manner, rejecting the numerous fables which they adopted, and adding the improvements of the moderns, which are so numerous, that they actually make up the bulk of natural history. The delight which I found in reading Pliny, first inspired me with the idea of a work of this nature. Having a taste rather classical than scientific, and having but little employed myself in turning over the dry labours of modern system-makers, my ear- liest intention was to translate this agreeable writer, and by the help of a commentary to make my work as amusing as I could. Let us dignify natural history never so much with the grave ap- pellation of a useful science, yet still we must confess, that it is the occupaticn of the idle and the speculative, more than of the busy and the ambitious part of mankind. My intention, there-- fore, was to treat ■what 1 then conceived to be an idle subject in an idle manner ; and not to hedge round plain and simple narra- tives with hard words, accumulated distinctions, ostentatious learning, and disquisitions that produced no conviction. Upon the appearance, however, of Mr Buffer's work, I dropped my former p!au, and adopted the present, being convinced, by his manner. X PREFACE TO THE ORIGINAL EDITION. that the best imitation of the ancients was to write from our own feelings, and to imitate nature. It will be my chief pride, therefore, if this work may be found an innocent amusement for those who have nothing else to em- ploy them, or who require a relaxation from labour. Professed naturalists ^vill, no doubt, find it superficial ; and yet I should hope that even these will discover hints and remarks, gleaned from various reading, not wholly trite or elementary. 1 would wish for their approbation. But my chief ambition is to drag up the obscure as is recorded in Boswell's Life, " Goldsmith is now writing a Natu- ral History, and he will make it as entertaining as a Persian tale." Goldsmith's work, indeed, did much to render Natural History a popular study in this country; for, important and in- teresting as the science is, it was late in the progress of know- ledge, both as regards ancient and modern times, before it as- sumed a regular form, or began to be generally cultivated. In Greece, many of the sciences had been successfully prosecuted, and the fine arts had attained maturity, before Aristotle gave the first outline in Natural History: in Rome, taste and genius had passed their meridian, before the elder Pliny collected his singu- lar medley of pi'ecious facts and idle fancies, which is the only valuable work in Natural History to be met with in Roman literature : and in our own times, the heroes of almost every other science had flourished before BufFon and Linnseus appeared. Goldsmith, it is true, cannot be classed with these great natural- ists in the extent and originality of his researches; yet, if he added little to the science, he divested it of much of its obscurity, and by the inimitable graces of his style and manner, threw a sharm over it, which was new to the English reader, and the ef- fect of which, in renderln' the science popular, has been, and to this day is, great and ext isive. Xll ADVERTISEMENl- lO THE PRESENT EDITION. With all its attractions, however, his work — owing to the im- Jjerfect state of information which obtained in the Author's time on many branches of the science— is not free from errors, and at this day cannot be held either as conaplete or scientific in its sys- tem. To correct its mistakes and supply its deficiencies are, there- fore, leading objects of the present edition ; and while the origi- nal text of the Author — which has so long delighted, and can never fail to delight the general reader — is faithfully retained, such additions are made to it in the shape of Notes as the present improved state of the science calls for. These Notes are thus dis- tinguished : the references to them consist of an asterisk or dag- ger, while the references to Dr Goldsmith's own notes, or to notes not peculiar to this edition, consist of figures. It is in scientific details that Goldsmith is chiefly deficient ; and the Editor has, therefore, been careful to give as much of these within his Notes as would tend to render the work more com- plete as a system of natural history, without encumbering its spirit, or dimming its attractions. This necessarily left him little room for the inti'oduction of illustrative anecdotes ; and as these form not only an interesting, but a most important point of natural history, he has been led to devote a supplemental volume entirely to them. By this means, he trusts the value of the work will be increased, and it will have a claim to completeness much beyond that of any other edition. Jn the prosecution of his labours, the Editor has derived great advantage from the writings of Wilson, Rennie, Knapp, Selby, Bennet, Vigors, Loudou, Jamieson, Audabon, and other jjopu- lar modern naturalists. But he begs, in an especial manner, to acknowledge his obligations to the highly interesting and valua- ble Supplements, appended by Mr GriflBth, Mr Pidgeon, and Major Smith, to the English edition of Baron Cuvier's Animal Kingdom. These gentlemen have proved themselves worthy co- adjutors of the great Baron in his splendid r£searches; and it is from devoted leaders like these, that so great an impulse has been given in the present day to the study of natural history. G.V J ,^* R . S.-vtt. .' i'aiie,-igian.2MonaolianJi2teafo. 4 Jme>-(caJ2.5 3taldii.6 New ZTtfUanA^r . G.V* / numpanse . SJ^iU Bottom MonJocy. 3 Entelhcs MonJcet/. V CbOuiichina J)? ^ JProbo.tci-f Z)? e Brouii B,/ JfoflHio. 2 LotujJC.ireilll^' 3 Spe,:h-e l'htf/l.j.sfjniia„4 Triiiiraii-A ''hliinryf'}u'r)is.iricridxi.Ni/>tcrna,6:Ri2j¥lessfiytrvnjjra..7RadiataiXt>le ."Slum II') Mt'Ir .i/J.f/i/' Clrrs.9nhtl£fO.10 Tf^vrec. I'uIiliAr-.lJ.y -4i-.li_4 PuU.a-toa Jci'fdias^ow^ GX I Large Water SpanieJ,. 2 Fox Soiuid 3 Spanish Pointer 4 Dalrruttian, D? 5 Sliepherds Doff. 6 Ckj- D? 7 Greenland D? S N^ev'foiouU l -/ i .tuuoir.i^ i ,. v.',-/> pyrif.6 -Sj/otted^Or-duymx.? ffhite. 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The world may be considered as one vast mansion, where man Las been admitted to enjoy, to admire, and to be grateful. The first desires of savage nature are merely to gratify the impor- tunities of sensual appetite, and to neglect the contemplation of things, barely satisfied with their enjoyment : the beauties of nature, and all the wonders of creation, have but little charms for a being taken up in obviating the wants of the day, and anxi- ous for precarious subsistence. Philosophers, therefore, who have testified such surprise at the want of curiosity in the ignorant, seem not to consider that they are usually employed in making provisions of a more im- portant nature ; in providing rather for the necessities than the am.usements of life. It is not tiU our more pressing wants are sufficiently supplied, that we can attend to the calls of curiosity; so that in every age scientific refinement has been the latest eflfort of human industry. But human curiosity, though at first slowly excited, being at last possessed of leisure for indulging its propensity, becomes one of the greatest amusements of life, and gives higher satis- factions than what even the senses can aflTord, A man of this disposition turns all nature into a magnificent theatre, replete with objects of wonder and surprise, and fitted up chiefly for his happiness and entertainment : he industriously examines all things, from the minutest insect to the most finished ani- mal ; and, when his limited organs can no longer make the dis- quisition, he sends out his imagination upon new inquiriee, A ■e HISTOR\ OF Nothing, therefore, can ba more august and striking than the idea which his reason, aided by his imagination, furnishes of tlie iniiverse around him. Astronomers tell us, that this earth .ihich we inhabit, forms but a very minute part in that great as- semblage of bodies of which the world is composed. It is a million of times less than the sun, by which it is enlightened. The planets also, which, like it, are subordinate to the sun's in- fluence, exceed the earth a thousand times in magnitude. These, which were at first supposed to wander in the heavens without an^j fixed path, and that took their name from their apparent devia- tions, have long been found to perform their circuits with great ex- actness and strict regularity. They have been discovered as form- ing, with our earth, a system of bodies circulating round the sun, all obedient to one law, and impelled by one common influence. Modem philosophy has taught us to believe, that, when the great Author of nature began the work of creation, he chose to operate by second causes ; and that, suspending the constant exertion of his power, he endued matter with a quality, by which the uni- versal economy of nature might be continued without his im- mediate assistance. This quality is called attraction ; a sort of approximating influence, which all bodies, whether teiTestrial or celestial, are found to possess j and which in all increases as the quantity of matter in each increases. • The sun, by far the • Although we are indebted to Sir Isaac Newton for the complete dis- covery of the law of universal gravitation, and its application to the explan- ation of the planetary motions, yet, the existence of the law had been surmised by different philosophers, both of ancient and modern times. Copernicus, the celebrated restorer of the true systemof astronomy, in speaking of the gravity of terrestrial bodies, by which they tend towards the centre of the '•arth, and to which the figure of the earth is owing, observes, that it is highly reasonable to suppose, that by a like principle, diffused from the sun ;ind planets, their figures are preserved in their various motions ; and Fer- mat, a mathematician of great eminence, wJio lived in the 15th century .ippears to have had accurate notions, to a certain extent at least, of the II ature of this law ; for he says, that the weight of a body is the sum " f the tendencies of each particle to every particle of the earth ; and among the moderns he is the first that made this remark. The justly celebrated Kepler, however, extended his views still farther; for in his Epitome Astronomic Copernicante, he says, that if there be supposed two bodies placed out of the reach of all external forces, and at perfect liberty to move, they would approach each other with velocities inversely proportionat to their quantities of matter ; the moon, says he, and the earth mutually at. tract each other, and are prevented from meeting by their revolution rounj THE EARTH. 3 greatest body in our system, is, of consequence, possessed of muca the greatest share of this attracting power ; and all the planets, af which our earth is one, are, of course, entirely subject to its juperior influence. Were this power, therefore, left uncontrol- their oommon centre of attraction ; and he says, that the tides of the ocean are the effects of the moon's attraction, heaping up the waters immediately under her. Thee, adopting the opinion of Dr Gilbert, that the earth is a great magnet, he explains how this mutual attraction will produce a deflec. tioQ into a curvilineal path. Dr Hooke appears to have had very accurate general notions of tlie nature of the mutual attraction of the celestial bodies ; for, at a meeting- of the Royal Society in the year 1666, he expressed himself as follows : " I will explain a system of the world very different from any yet received, and it is founded on the three following positions. 1. That all the heavenly bodies have not only a gravitation of their parts towards their own proper centre, but that they mutually attract each other within their spheres of action. 2. That all bodies having a simple motion, wiU continue to move in a straight line, unless continually deflected from it by some extraneous force, causing them to describe a circle, an ellipse, or some other curve. 3. That tins attraction is so much the greater as tlie bodies are nearer. Aa to the proportion in which those forces diminish by an increase of distance, I own," said he, " I have not discovered it, although I have made some ex- periments to this purpose : I leave this to others, who have time and know- ledge sufficient for this task." Previous to this period, Dr Hooke had ex- hibited to the Society an experiment, with a \ iuw to show how a motion in a curve might be produced in consequence of a tendency in a body towards a centre. A ball suspended by a thread from the ceiling was made to revolve about another ball laid on a table immediately below the point of suspension. When the push given to the pendulous ball was properly adjusted to its devia- tion from the perpendicular, it described a perfect circle round the ball on the table, but when the push was very great, or very smaU, it described an ellipse, having the other ball in its centre. Dr Hooke showed that this was the operation of a deflecting force directly proportional to the distance from the other ball; but he added, that although this illustrated the planetary motions in some degree, yet it was not suitable to their cause ; for the planets describe ellipses, having the sun not in the centre, but in one of their foci ; therefore they are not retained by a force proportional to their distance from the sun. In these rertiarks, we have a clear and modest account of a rational theory ; and it must be inferred from them, that Dr Hooke had an. ticipated Newto. in describing the general nature of the planetary motions, although it is solely to the latter that we owe the discovery of the precise law of the force by which the very motions we observe are produced. To this extent the true theory of the motions of the heavenly bodies hnd been discovered, or rather conjectured, when Sir Isaac Xewton turned his at- t«ntion to the subject. The circumstances under which he discovered tlie true theory of the planetary motions, are stated by Dr Pemberton, in his preface to this T'iew of Sir Isaac Newton's Philosophy. They are in sub. stance as follows: He had retired from Cambridge to his country house in the year 1666, on account of the plague ; and one day as he sat alone in his car- din, reflecting on the power by which all terrestrial bodies gravitate toward* 4 HISTORY OF led by any other, the sun must quickly have attracted all the bodies of our celestial system to itself; but it is equally coun- teracted by another power of equal efficacy ; namely, a pro- gressive force, which each planet received when it was the earth, it orcuired to him, that as this power 13 not sensibly diminished at any distance to which we can recede frona the earth's centre, there seemed reason to conclude that it extended much farther than was commonly supposed, and even might extend as far as the moon ; and if this were true, he concluded that her motion would be influenced by it, and that probably it was this very force which retained her in her orbit. However, although the force of gravity be not sensibly less at the tops of the highest mountains, than at the ordinary level of the earth's surface, he conceived it to be very possible, that at so great a distance as that of the moon, it might be considerably different. To make an estimate of what might be the degree of the diminution, he con- sidered that if the moon be retained in her orbit by the force of gravity, no doubt the primary planets are carried round the sun by a like power ; and by comparing the periods of the several planets with their distances from the 6un, he found that if any power hke gravity kept them in their orbits, its strength must decrease in proportion, as the squares of the distances increase : but in making this conclusion, he supposed that the orbits of the planets were circles, having the sun in their centre, from which figure the greater part of them do not much differ. Supposing, therefore, the force of gravity to extend as far as the moon, and to decrease according to this ratio, he com. puted whether that force would be sufficient to keep the moon in her orbit ; but having no books at hand, by which he might ascertain the true magni- tude of the earth, he was obliged to employ in his calculation the erroneous estimate at that time commonly received among geographers and seamen, namely, that a degree of latitude on the earth's surface was 60 English miles. Now, as the degree contains in reality about 69J miles, his computation of course did not agree with the phenomena ; and on this account, he laid aside at that time all further consideration of the subject. Some years after, in con. sequence of a letter he received from Dr Hooke, he investigated the nature of the path which a body would describe, if it were let fall from any high place, taking into account the rotation of the earth ; and on this occasion, he resumed his former train of reflections concerning the motion of the moon. He had now, however, the advantage of knowing pretty nearly the exact magnitude of the earth, in consequence of tlie measurement of an arc of the meridian made in France by Picard ; and he had the inexpressible satisfaction of finding that his calculation agreed exactly with what it ought to be, if the opinion he had formed was correct. He therefore concluded that his conjee- ture was correct, and that the moon was really kept in her order by the force of gravity, which decreased according as the square of the distance increased, agreeably to what he had supposed. It is said, that as the calculation drew to a close, the mind of Newton was so much agitated by the importance of the discovery he was on the point of making, that he was obliged to desire a friend to finish them. This is not to be wondered at, when we considiv the great revolution which he foresaw he was about to produce in the opt- ions of mankind, and the immense fabric of science that might be built ' n his discovery. THE EARTH. O impelled forward by tbe divine Architect, upon its first forma- tion. The heavenly bodies of our system being thus acted upon by two opposing powers ; namely, by that of attraction, which draws them towards the sun ; and that of impulsion, which drives them straight forward into the great void of space ; they pursue a track between these contrary directions ; and each, like a stone whirled about in a sling, obeying two opposite forces, circulates round its great centre of heat and motion. In this manner, therefore, is the harmony of our planetary system preserved The sun, in the midst, gives heat, and light, and circular motion, to the planets which surround it ; Mercury, Venus, the Earth, Mars, Jupiter, and Saturn,* perform their * Since Goldsmith's time, five other planetary bodies, (Uranus, Ceres, Pal- las, Juno, Vesta,) belonging to our solar system, have been discovered. On the 13th of March, 1781, Ur Herscliel discovered a new planet without the orbi^ of Saturn, which was first named by foreign astronomers, after its observer, the Herschel, but called by Heiscltel himself (in honour of George III.) the Georgium Sidus — although both these names are fast nking, and Uranm is the appellation now almost universally adopted. The Uranus is the most remote of our planets, so far as discovered, ■ irculating about the sun at the astonishing distance of 1800 million miles, and performing its orbicular revolution in about SO of our years. Its diameter is 35,112 miles. It has six secondary planets or moons. The other four planets are small. Ceres was discovered situated between the orbits of Mars and Jupiter, on the 1st of January, ISOl, by M. Piazzi, a Sicilian astronomer. It performs its revolution round the sun in about four years. Pallas was discovered also situated between the orbits of Mars and Jupiter, on the 28th March, 1802, by Dr Olbers of Bremen. Juno was discovered by Mr Harding, at the observatory of Lilienthal, near Bremen, on the 1st day of September, ISOi. It is likewise situated between file orbits of Mars and Jupiter ; and performs its revolution round the sun in 5 years and 182 days. Vesta was discovered by Dr Olbers, on the 29th of March, 1807. It is also situated between the orbits of Mars and Jupiter; and performs its revolution round the sun in 3 years and 182 days. — The diameters of these planets (which must, I'.owever, be considered as doubtful) have been given a follows : — Ceres, 102i miles ; Pallas, 2099 miles ; Juno, 1426 miles; Vesta, 233 miles. It was supposed by some astronomers that a planet existed between the orbits of Jupiter and Mars. The discovery of Ceres confirmed this conjecture ; but tlie opinion v^iiich it seemed to establish respecting the harmony of the solar system, appeared to be completely over- turned by the discovery of Pallas and Juno. Dr Olbers, however, considers that these small celestial bodies are merely the fragments of a larger planet, which had been burst asunder by some internal convulsion, and that several more might yet be discovered between the orbits of Mars and Jupiter. Some writers suppose the meteoritic stones which fall upon our earth to be smail portions of this dissevered planet. In Brewster's Encyclopaedia a theory is Started respecting the origin of Ceres and Pallas, wluch is plausible and A 3 6 HISTORY OF constant circuits at different distances, each taking up a time to complete its revolutions proportioned to the greatness of the circle which it is to describe. The lesser planets also, which are atten- ru rious. It is thus stated : " A comet appeared in the year mO, and was carefully observed for nearly four mouths by M. Messier. When Prospc-rin and Piugre applied themselves to calculate the elements of its orbit, they tound that a parabolic path would not represent the observations of Messier, and hence they suspected that its orbit might be sensibly elliptical. M. Lexell of St Petersburgh computed its elements in an elliptical orbit, and he found that its period was five years and a half, and that its greatest distance from the sun did not much exceed that of Jupiter. This curious subject was in. vestigated rather unsuccessfully by Slop, Sejour, and Lambert ; and a few years ago it attracted the particular notice of the National Institute of France. At the request of that learned body, Dr Biirekhardt repeated all the calcula- tions with the utmost care, and the result of his investigations was a com. plete confirmation of Lexell's conclusions. Here then is a most singular anomaly in the motion of this comet. While all the other comets which have been observed, move in orbits stretching far beyond the limits of the solar system, and revolve in periods of long duration, the comet of 1770 never wan- ders beyond the orbit of Saturn, and completes its revolution in the short period of five years and a half. The return of this body, therefore, was con- fidently expected by astronomers; but though it must now have completed nearly eight revolutions round the sun, and though more observations have been made in the heavens during the last 40 years than perhaps during the two preceding centuries, yet the comet of 1770 has never re-appeared. We are consequently entitled to conclude, that the comet of 1770 is lost, which could happen only from its uniting with one of the planets, whose orbits it crossed. Now, if such a union took place, two consequences would obviouely flow from it. The planet would suffer a sensible derangement in its motions, and its atmosphere would receive a vast accession of that nebulous matter, of which the comets are often wholly composed. Here, then, we have two distinct criteria to enable us to ascertain the individual planet by which the comet was attracted. The path of the comet intersects the orbits only of Venus, the Earth, Mars, the four new planets, and Jupiter, and therefore it must have united with one of these bodies, or with their satellites. Now, eince the year 1770, neither Venus the Earth, Mars, nor Jupiter, have suf- fered the smallest derangement of this kind, nor have they received any visi. ble addition to their atmospheres, We must, therefore, look to the four new planets for some indication of the presence of a comet, and if they exhibit any phenomena that are unequivocally of this description, we must consider such a coincidence as a strong proof of the theory, or as one of the most wonderful facts in the history of science. Two of the new planets, Ceres , and Pallas, exhibit, in the form and position of their orbits, evident marks of some great derangement ; but as this may have arisen from that explosive lorve, by which they seem to have been separated from a larger planet, we are not entitled to regard it as a proof of the present theory. But though we cannot employ our first criterion either for or against the theory, the second applies with irresistible force, and we would entreat the particular attention of our readers to this single point. The two planets Ceres and I'allas, are actually aurrouo ieil with atmospheres of an immense size. Tha THE EARTH. 7 ilants upon some of the greater, are subject to the same laws ; they circulate with the same exactness ; and are, in the same manner, influenced by their respective centres of motion. Besides those bodies which make a part of our peculiar system, and which may be said to reside within its great circum- ference, there are others that frequently come among us, from the most distant tracts of space, and that seem lijce dangerous intruders upon the beautiful simplicity of nature. These are Comets, whose appearance was once so terrible to mankind ; and the theory of which is so little understood at present : all we know is, that their number is much greater than that of the planets ; and that, like these, they roll in orbits, in some measure obedient to solar influenc*?.* Astronomers have endeavoured to atmosphere of Ceres is 675 English miles high, while that of Pallas rises to the height of 468 miles. Now the height of any of these atmospheres is greater than the united heights of the atmospheres of all the other planet?, and is above a thousand times higher than it ought to have been, according to the ratio which exists between the globes and the atmospheres of all the other bodies of the system. Astronomers were so forcibly struck with the magnitude of these atmospheres, that a dispute arose whether Ceres and Pallas should be called planets or comets, and the discussion terminated, by giving them tlie name of asteroids, a class of bodies which were supposed to partake of the nature both of planets and comets. But to draw this argument still closer upou the subject, let us inquire from what other source these atmo- spheres could be derived, if they were not imparted by the comet of 1770. If the four new planets are the fragments of a larger body, endowed with an extensive atmosphere, each fragment would obviously carry off a portion of atmosphere proportioned to its magnitude ; but two of the fragments, Juno and Vesta, have no atmosphere at all, consequently the atmospheres of Ceres and Pallas could not have been derived from the original planet, but must have been communicated to them at a period posterior to the divergency of the fragments. It would have been a satisfactory addition to the preceding arguments, if we had been able to show, by direct calculation, that Ceres and Pallas were at the same instant with the comet in that part of their or- bits which was crossed by its path, and that the position of the planes of the orbits was such, ls to permit a near approximation. But as we have no data sufficiently correct for such a calculation, we must leave this part of the sub- ject to some future opportunity. There is one fact, however, which in some measure supplies its place, and which is therefore worthy of particular no- tice. The nodes of the comet of 1770, lie exactly between the nodes of Ceres and Pallas, an arrangement which is absolutely indispensable to the truth oi. the preceding theory." * "When examined through a good telescope, a comet resembles a mass of •queous vapours encircling an opaque nucleus of different degrees of dark, ness in different comets, though sometimes, as in the case of several dis. covered by Dr Herschel, no nucleus can be Been. As the comet edvaucea 8 HISTORY OF calculate the returning periods of many of them ; but experience has not, as yet, confirmed the veracity of their investigations. Indeed, vi^ho can tell, when those wanderers have made their excursions into other M'orlds and distant systems, what obstacles may be found to oppose their progress, to accelerate theil motions, or retard their return ? towards the sun, its faint and nebulous light becomes more brilliant, and its luminous train gradually increases in length. When it reaches its perihelion, the intensity of its light, aud the length of its tail, reach their maximum, and sometimes it shines with all the splendour of Venus. During its retreat from the perihelion, it is shorn of its splendour, it gradually resumes its nebulous appearance, and its tail decreases in magnitude till it reaches such B distance from the earth, that the attenuated light of the sun, which it re. fleets, ceases to make an impression on the organ of sight. Traversing un. seen the ri^mote portion of its orbit, the comet wheels its ethereal course far beyond tlio limits of our system. What region it there visits, or upon what dHstiiiation it is sent, the limited powers of man are unable to discover. After the lapse of years, we perceive it again returning to our system, and tracing a portion of the same orbit round the sun, which it had formerly described. It would be a waste of time to detail the various wild and extra. vagant opinions which have been entertained respecting these interesting stars. During the ages of barbarism and superstition, they were regarded «s the harbingers of awful convulsions, both in the political and in the phy- sical world. Wars, pestilence, and famine, the dethronement of kings, the fall of nations, and the more alarming convulsions of the globe, were the dreadful evils which they presented to the diseased and terrified imaginatioas of men. As the light of knowledge dissipated these gloomy apprehensions, the absurdities of licentious speculation supplied their place, and all the in- genuity of conjecture was exhausted in assigning some rational office to these wandering planets. Even at the beginning of the 18th century, the friend and companion of Newton regarded them as the abode of the damned. Anxious to know more tlian what is revealed, the fancy of speculative theo. logians strove to discover the frightful regions in which vice was to sufftr its merited punishment ; and the interior caverns of the earth had, in general, been regarded as the awful prison-house in which the Almighty was to dis- pense Uie severities of justice. Mr Whiston, however, outstripped all his predecessors in fertility of invention. He pretended not only to fix the resi. dence of the damned, but also the nature of their punishment. Wheeled from the remotest limits of the system, the chilling regions of darkness and cold, the comet wafted them into the very vicinity of the sun ; and thua alternately hiuried its wretched tenants to the terrifying extremes of chil. ling cold and devouring fire. By other astronomers, comets were destined for more scientific purposes. They were supposed to convey back to the planets the electric fluid which is constantly dissipating, or to supply the sun with the fuel which it perpetually consumes. They have been regarded also as the cause of the deluge ; and v/e must confess, that if a natural cause is to be sought for that great event, we can explain it only by the shock of some celestial body. The transient effect of a comet passing near the earth, coul.t THE EAUTH. 9 But what we have hitherto attempted to sketch, is but a smni! part of that great fabric in which the Deity has thought proper to manifest his wisdom and omnipotence. There are multitudes of other bodies, dispersed over the face of the heavens, that lie too remote for examination : these have no motion, such as the planets are found to possess, and are, therefore, called fixed scarcely amount to any great convulsion ; but if the earth were actually to receive a direct impulse from one of these bodies, the consequences irould be awful. A new direction would be given to its rotatory motion, and the globe would revolve round a new axis. The seas, forsaking their ancient beds, would be hurried by their centrifugal force, to the new equatorial re- gions ; islands and continents, the abodes of men and animals, would be covered by the universal rush of the waters to the new equator, and every vestige of human industry and genius at once destroyed. The chances against such an event, however, are so very numerous, that there is no dread of its occurrence. Various opinions have been entertained by astrono- mers respecting the tails of comets. They were supposed by Appian, Cardan, and Tycho Brahe, to be the light of the sun transmitted through the nucleus of the comet, which they believed to be transparent like a lens. Kepler thought, that the impulsion of the solar rays drove away the denser parts of the comet's atmosphere, and thus formed the tail. Descartes ascribes the tail to the refraction of light by the nucleus. Newton maintained, that it is a thin vapour raised by the heat of the sun from the comet. Euler asserts, that the tail is occasioned by the impulsion of the solar rays driving off the atmosphere of the comet ; and that the curvature observed in the tail is the joint effect of this impulsive force, and the grravitation of the atmospherical particles to the solid nucleus. Mairan imagines that comets' tails are por. tions of the sun's atmosphere. Dr Hamilton of Dublin supposes them to be streams of electric matter ; and Biot supposes with Newton, that the tails are vapours produced by the excessive heat of the sun ; and also, that the comets are solid bodies before they reach their perihelion ; but that they are afterwards either partly or totally converted into vapoiir by the intensity of the solar heat Of all these theories, that of Euler seems to be most philo- sophical. Since the comets are composed chiefly of nebulous matter, and have very large atmospheres, the external atmospheric strata must be drawn towards the comet by very slight powers of attraction, and will therefore yield to the smallest impulse. From the great density of the planets, on the contrary, and the small size of their atmospheres, the external strata are at- tracted towards them with a very great force, and therefore cannot yield, like those of the comets, to a slight impulse. Hence we see the reason why the comets have tails, while none of the planetary bodies exhibit such a phenomenon. Whatever opinion may be entertained of this explanation, it must, at least, be admitted, that if light is a material substance, the atmo. spherical particles of a comet may have their gravity diminished to such a degree, either by their distance from its centre, or by the rarity of the nu- deus, as to yield to the impulse of the solar rays, and be forced behind th» nucleus, in the same maDner as smoke yields to the impulse of the geotiesk hreezc. 10 HISTORY OF stars ; and from their extreme brilliancy, and their inunent« distance, philosophers have been induced to suppose them to be suns, resembling that which enlivens our system. As the ima- gination also, once excited, is seldom content to stop, it has furnished each with an attendant system of planets belonging to itself; and has even induced some to deplore the fate of thosa systems, whose imagined suns, which sometimes happens, have become no longer visible. But conjectures of this kind, which no reasoning can ascer- tain, nor experiment reach, are rather amusing than useful. Though we see the greatness and wisdom of the Deity in all the seeming worlds that surround us, it is our chief concern to trace him in that which we inhabit. The examination of the earth, the wonders of its contrivance, the history of its advantages, or of the seeming defects in its formation, are the proper business of the natural historian. A description of this earth, its ani. mals, vegetables, and minerals, is the most delightful entertain- ment the mind can be furnished with, as it is the most interest- ing and useful. I would beg leave, therefore, to conclude these common -place speculations, with an observation which, I hope, is not entirely so. A use, hitherto not much insisted upon, that may result from the contemplation of celestial magnificence, is, that it will teach us to make an allowance for the apparent irregularities we find below. Whenever we can examine the works of the Deity at a proper point of distance, so as to take in the whole of his de- sign, we see nothing but uniformity, beauty, and precision. The heavens present us with a plan, which, though inexpressibly magnificent, is yet regular beyond the power of invention. Whenever, therefore, we find any apparent defects in the Earth, which we are about to consider, instead of attempting to reason ourselves into an opinion that they are beautiful, it will be wiser to say, that we do not behold them at the proper point of distance, and that our eye is laid too close to the objects, to take in the regularity of their connection. In short, we may conclude, that God, who is regular in his great productions, acts with C(iual uniformity in the little. Tlih LAillH. II CHAP. 11. A SHORT SURVEY OF THE GLOBE, FROM THE LIGHT OF ASlHONOn AND GEOGRAPHY. All the sciences are, in some measure, linked with each other, and before the one is ended, the other begins. In a na- tural history, therefore, of the earth, we must begin with a short account of its situation and form, as given us by astronomers and geographers : it will be sufficient, however, upon this occasion, just to hint to the imagination, what they, by the most abstract reasonings, have forced upon the understanding. The earth which we inhabit is, as has been said before, one of those bodies which circulate in our solar system ; it is placed at a happy mid- dle distance from the centre ; and even seems, in this respect, privileged beyond all other planets that depend upon our great luminary for their support. Less distant from the sun than [ Uranus,] Saturn, Jupiter, and Mars, and yet less parched up than Venus and Mercur}', that are situate too near the violence of its power, the Earth seems in a peculiar manner to share the bounty of the Creator : it is not, therefore, without reason, that man- kind consider themselves as the peculiar objects c€ his providence and regard. Besides that motion which the earth has round the sun, the circuit of which is performed in a year, it has another upon its own axis, which it performs in twenty-four hours. Thus, like a chariot-wheel, in has a compound motion ; for while it goes forward on its journey, it is all the while turning upon itself. From the first of these two arises the gratefid vicissitude of the seasons ; from the second, that of day and night. It may be also readily conceived, that a body thus wheeling in ircles will most probably be itself a sphere. The earth, beyond all possibility of doubt, is fomid to be so. Whenever its shadow happens to fall upon the moon, in an eclipse, it appears to be always circular, in whatever position it is projected ; and it is easy to prove, that a body which in every position makes a cir- cular shadow, must itself be round. The rotundity of the earth may be also proved from the meeting of two ships at sea : the topmasts of each are the first parts that are discovered by 6oth, the under parts being hidden by the convexity of tlie 12 HlSTuaV OF globe which rises between tnem. The ships, in this instance, may be resembled to two men who approach each other on the opposite sides of a hill ; their heads will first be seen, and gra. dually as they come nearer they will come entirely into view.* However, though the earth's figure is said to be spherical, w e ought only to conceive it as being nearly so. It has been found in the last age to be rather flatted at both poles, so that its form is commonly resembled to that of a turnip. The cause of this swelling of the equator is ascribed to the greater rapidity of the motion with which the parts of the earth are there carried round ; and which, consequently, endeavouring to fly off, act in opposi- tion to central attraction. The twirling of a mop may serve as a homely illustration; which, as every one has seen, spreads and grows broader in the middle as it continues to be turned round. As the earth receives light and motion from the sun, so it derives much of its warmth and power of vegetation from the same beneficent source. However, the diflferent parts of the globe participate of these advantages in very diflferent propor- tions, and accordingly put on very different appearances ; a polar prospect, and a landscape at the equator, are as opposite in tlieir appearances as in their situation. The polar regions, that receive the solar beams in a very ob- lique direction, and continue for one half of the year in night, receive but few of the genial comforts which other parts of the world enjoy. Nothing can be more mournful or hideous than the picture which travellers present of those wretched regions. The ground,' which is rocky and barren, rears itself in every place in lofty mountains and inaccessible cliffs, and meets the mariner's eye at even forty leagues from shore. These precipices, frightful in themselves, receive an additional horror from being constantly covered with ice and snow, which daUy seem to ac- cumulate, and fill all the valleys Avith increasing desolation. The few rocks and cliff's that are bare of snow, look at a distance of * other proofs of the earth's rotundity might be adduced, the most practi. cal of which is that derived from the many voyages performed around it- navigators pursuing a due course east or west having returned to the samo place whence tliey set out, which could not have happened were the earth a plane. 1 Crantz's History of Greenland, p. 3. THE EAllTH. 13 a dark brovvn colour, and quite naked. Upon a nearer approach, however, they are found replete with many different veins of coloured stone, here and there spread over a little earth, and a scanty portion of grass and heath. The internal parts of the country are still more desolate and deterring. In wandering through these solitudes, some plains appear covered with ice, that at first glance, seem to promise the traveller an easy jour- ney. ' But these are even more formidable and more unpassable than the mountains themselves, being cleft with di-eadful chasms, and every where abounding with pits that threaten certain de- struction. The seas that surround these inhospitable coasts are still more astonishing, being covered with flakes of floating ice, that spread like extensive fields, or that rise out of the water like enormous mountains. These, which are composed of materials as clear and transparent as glass,* assume many strange and fantastic appearances. Some of them look like churches or castles, with pointed turrets ; some like ships in full sail ; and people have often given themselves the fruitless toil to attempt piloting the imaginary vessels into harbour. There are still others that appear like large islands, with plains, valleys, and hills, which often rear their heads two hundred yards above the level of the sea ; and although the height of these be amazing, yet their depth beneath is still more so ; some of them being found to sink three hundred fathom under water. The earth presents a very different appearance at the equator, where the sunbeams, darting directly downwards, burn up the lighter soils into extensive sandy deserts, or quicken all the mois- ter tracts with incredible vegetation. In these regions, almost ftll the same inconveniences are felt from the proximity of the Bun, that in the former were endured from its absence. The deserts are entirely barren, except where they are found to pro- duce serpents, and that in such quantities, that some extensive plains seem almost entirely covered with them.- It not unfrequently happens also, that this dry soil, which is 60 parched and comminuted by the force of the sun, rises with the smallest breeze of wind ; and the sands, being composed of parts almost as small as those of water, they assume a similar 1 Crantz's History of Greenland, p. 22. 8 Ibid, p- 27. 3 Adanson'a Description of Seneg it. B 14 HISTORY or appearance, rolling onward in waves like those of a troubled sea, and overwhelming all they meet with inevitable destruction. On the other hand those tracts which are fertile, teem with vegetation even to a noxious degree. The grass rises to such a height as often to require burning ; the forests are impassable from underwoods, and so matted above, that even the sun, fierce Bs it is, can seldom penetrate.' These are so thick as scarcely to be extirpated ; for the tops being so bound together by the climbing plants that grow round them, though a hundred should be cut at the bottom, yet not one would fall, as they mutually support each other. In these dark and tangled forests, beasts of various kinds, insects in astonishing abundance, and serpents of surprising magnitude, find a quiet retreat from man, and are seldom disturbed except by each other. In this manner the extremes of our globe seem equally unfitted for the comforts and conveniences of life ; and although the ima- gination may find an awful pleasure in contemplating the fright- ful precipices of Greenland, or the luxurious verdure of Africa, yet true happiness can only be found in the more moderate cli- mates, where the gifts of natiure maybe enjoyed, without incur- ring danger in obtaining them. It is in the temperate zone, therefore, that all the arts of im- proving nature, and refining upon happiness, have been invented : and this part of the earth is, more properly speaking, the theatre of natural history. Although there be millions of animals and vegetables in the unexeplored forests under the line, yet most of these may for ever continue unknown, as curiosity is there repressed by surrounding danger. But it is otherwise in these delightful regions which we inhabit, and where this art has had its beginning. Among us there is scarce a shrub, a flower, or an insect, without its particular history j scarce a plant tliat could be useful, which has not been propagated j nor a weed that could be noxious, which has not been pointed out. CHAP. III. A VIKW OF THE SURFACE OF THE EARTH. When we take a slight survey of the surface of our globe, a thousand objects offer themselves, which, though long known, 1 Linnaei Amaenit. vol. vi. p. 67. THE EARIrf. 15 yet still demand oiu' curiosity. The most obnous beauty that every where strikes the eye is the verdant covering of the earth, which is formed by a happy mixture of herbs and trees of various magnitudes and uses. It has been often remarked, that no colour refreshes the sight so much as green : and it may be added, as a further proof of the assertion, that the inhabitants of those places where the fields are continually white with snow, generally become blind long before the usual course of nature. This advantage, which arises from the verdure of the fields, is not a little improved by their agreeable inequalities. There are scarcely two natural landscapes that offer prospects entirely resembling each other ; their risings and depressions, their hills. and valleys, are never entirely the same, but always offer something new to entertain and refresh the imagination. But to increase the beauties of the face of nature, the landscape is enlivened by springs and lakes, and intersected by rivulets. These lend a brightness to the prospect ; give motion and coolness to the air ; and, what is much more important, fur- nish health and subsistence to animated nature. Such are the most obvious and tranquil objects that every where offer : but there are objects of a more awful and magnifi- cent kind ; the Mountain rising above the clouds, and topped with snow ; the River pouring down its sides, increasing as it runs, and losing itself, at last, in the ocean ; the Ocean spread- ing its immense sheet of waters over one half of the globe, swell- ing and subsiding at well-known intervals, and forming a communication between the most distant parts of the earth. If we leave those objects that seem to be natural to our earth, and keep the same constant tenor, we are presented with the great irregularities of nature : the burning mountain ; the abrupt precipice ; the unfathomable cavern ; the headlong cataract ; and the rapid whirlpool. K we carry our curiosity a little further, and descend to the objects immediately below the surface of the globe, we shall there find wonders still as amazing. We first perceive the earth, for the most part, Mng in regular beds or layers, every bed growing thicker in proportion as it lies deeper, and its con- tent, more compact and heavy. We shall find, almost wherever we make our subterranean inquiry, an amazing number of shells that once belonged to aquatic animals. Here and there, at a dis- 16 HISTORY OF tance from the sea, beds of oyster-shells, several yards thick, and many miles over ; sometimes testaceous substances of various kinds on the tops of mountains, and often in the heart of the hardest marble. These, which are dug up by the peasants in every country, are regarded with little curiosity ; for being so very common, they are considered as substances entirely terrene. But it is othenvise with the inquirer after nature, who finds them, not only in shape, but in substance, every way resembling those that are found in the sea ; and he, therefore, is at a loss to account for their removal. Yet not one part of nature alone, but all her productions and varieties, become the object of the speculative man's in- quiiy ; he takes different views of nature from the inattentive spectator ; and scarcely an appearance, how common soever, but affords matter of his contemplation ; he inquires how and why the surface of the earth has those risings and depressions which most men call natural ; he demands in what manner the moun- tains were formed, and in what consists their uses ; he asks from whence springs arise, and how rivers flow round the con- vexity of the globe ; he enters into an examination of the ebbings and flowings, and the other wonders of the deep ; he acquaints himself with the irregularities of nature, and endeavours to in- vestigate their causes ; by which, at least, he will become better versed in their history. The internal structure of the globe be- comes an object of his curiosity ; and although his inquiries can fathom but a very little way, yet, if possessed with a spirit of theory, his imagination will supply the rest. He will endeavour to account for the situation of the marine fossils that are found in the earth, and for the appearance of the different beds of which it is composed. These have been the inquiries that have splendidly employed many of the philosophers of the last and present age,' and, to a certain degree, they must be serviceable But the worst of it is, that, as speculations amuse the writel more than facts, they may be often carried to an extravagant length •, and that time may be spent in reasoning upon nature, \\ hich might be more usefully employed in writing her history. Too much speculation in natural history is certainly wrong ; but there is a defect of an opposite nature that does much more 1 r.uffon, Wood«'ard, Burnet, Whiston, Kirclier, Bourquat, Leibnitz, BtPDo, Ray, &c. THE EaKTH. 17 prejudice ; namely, thut of silencing all inquiry, by alleging the benefits we receive from a thing, instead of investigating the cause of its production. If I inquire how a mountain came to be formed ; such a reasoner, enumerating its benefits, answers, because God knew it would be useful. If I demand the cause of an earthquake, he finds some good produced by it, and alleges that as the cause of its explosion. Thus such an inquirer has constantly some ready reason for every appearance in nature, which serves to swell his periods, and give splendpur to his de. clamation ; every thing about him is, on some account or other, declared to be good ; and he thinks it presumption to scrutinize into its defects, or to endeavour to imagine how it might be better. Such wTiters, and there are many such, add very little to the advancement of knowledge. It is finely remarked by Bacon, that the investigation of final causes* is a barren study ; and like a \drgin dedicated to the Deity, brings forth nothing. In fact, those men who want to compel every appearance and every irregularity in nature into our service, and expatiate on their benefits, combat that very morality which they would seem to promote. God has permitted thousands of natural evils to exist in the world, because it is by their intervention that man is capable of moral evil; and he has permitted that we should be subject to moral evil, that we might do something to deserve eternal happiness, by showing that we had rectitude to avoid it CHAP. IV. A REVIEW OF THE DIFFERENT THEORIES OF THE EARTH. Human invention has been exjercised for several ages to account for the various iiregularities of the earth. While those philo- sophers, mentioned in the last chapter, see nothing but beauty, symmetry, and order; there are others, who look upon the gloomy side of nature, enlarge on its defects, and seem to con- Elder the earth, on which they tread, as one scene of extensive desolation.' Beneath its surface they observe minerals and waters confusedly jumbled together ; its diflferent beds of earth 2 Investigatio cansarum finalium sterilLs est, et veluti virgo Deo dedicata nil p&rit. 3 BuSbn's second discoiirset b3 13 HISTORY OP uregularly lying upon each other ; mountains rising from places that oiice were level ;' and hills sinking into valleys ; whole re- gions swallowed by the sea, and others again rising out of its bosom. All these they suppose to be but a few of the changes that have been wrought in our globe ; and they send out the imagination to describe its primeval state of beauty. Of those who have written theories describing the manner of the original formation of the earth, or accounting for its present appearances, the most celebrated are Burnet, Whiston, Wood- ward, and Buffon. As speculation is endless, so it is not to be wondered that all these differ from each other, and give opposite accounts of the several changes, which they suppose our earth to have undergone. As the systems of each have had their ad- mirers, it is, in some measure, incumbent upon the natural his- torian to be acquainted, at least, with their outlines : and, indeed, to know w^hat others have even dreamed in matters of science, i.s very useful, as it may often prevent us from indulging similar delusions ourselves, which we should never have adopted, but be- cause we take them to be wholly our own. However, as enter- ing into a detail of these theories is rather furnishing a history of opinions than things, I will endeavour to be as concise as I can. The first who formed this amusement of earth-making into system, was the celebrated Thomas Burnet, a man of polite learning and rapid imagination. His Sacred Theory, as he calls it, describing the changes which the earth has undergone, or shall hereafter undergo, is well known for the warmth with which it is imagined, and the weakness with which it is reason- ed ; for the elegance of its style, and the meanness of its philo- sophy. " The earth," says he, " before the deluge, was very differently formed from what it is at present : it was at first a fluid mass; a chaos composed of various substances, differing both in density and figure : those which were most heavy, sunk to the centre, and formed in the middle of our globe a hard solid body ; those of a lighter nature remained next ; and the waters, which were lighter still, swam upon its surface, and covered the earth on every side. The air, and all those fluids which were iighter than water, floated upon this also ; and in the same man- ner encompassed the globe ; so that between the surrounding 1 Sencc. Qiisest. lib. vi. cap. 2i, THE Earth. 19 body of waters, and the circumambient air, there was formed a coat of oil, and other unctuous substances, lighter than water. However, as the air was still extremely impure, and must have carried up with it many of those earthy particles with which it once was intimately blended, it soon began to defecate, and to depose these particles upon the oily surface already mentioned, which soon uniting, the earth and oil formed that crust, which soon became a habitable surface, giving life to vegetation, and dwelling to animals. " This imaginary antediluvian abode was very different from what we see it at present. The earth was light and rich ; and formed of a substance entirely adapted to the feeble state of in- cipient vegetation ; it was a uniform plain, every where covered with verdure ; without mountains, without seas, or the smallest, inequalities. It had no difference of seasons, for its equator was in the plane of the ecliptic, or, in other words, it turned directly opposite to the sun, so that it enjoyed one perpetual and luxuriant spring. However, this delightful face of nature did not long continue in the same state ; for, after a time, it began to ciack and open in fissures ; a circumstance which always suc- ceeds when the sun exhales the moisture from rich or mai'shy situations. The crimes of mankind had been for some time preparing to draw down the wTath of Heaven; and they, at length, induced the Deity to defer repairing these breaches in natiu-e. Thus the chasms of the earth every day became wider, and, at length, they penetrated to the great abyss of waters ; and the whole earth, in a manner, fell in. Then ensued a total disorder in the uniform beauty of the first creation, the terrene surface of the globe being broken down : as it sunk the waters gushed out in its place ; the deluge became universal ; all man- kind, except ei£ht persons, were destroyed, and their posterity condemned to toil upon the ruins of desolated nature." It only remains to mention the manner in which he relieves the earth from this universal wreck, which would seem to be as difficult as even its first formation : " These great masses of earth falling into the abyss, drew down with them vast quanti- ties also of air ; and, by dashing against each other, and breaking into small parts by the repeated violence of the shock, they, at length, left between them large cavities, filled with nothing but air. These cavities naturally offered a bed to receive the influent 20 HisTOitv or waters ; and in proportion as they lilled, the face of the earth became once more visible. . The higher parts of its broken sur- *kce, now become the tops of mountains, were the first that ap- peared ; the plains soon after came forward, and, at length, the whole globe was delivered from the waters, except the places ill the lowest situations ; so that the ocean and the seas are still a part of the ancient abyss, that have not had a place to return I.-ilands and rocks are fragments of the earth's former crust; kingdoms and continents are larger masses of its broken sub- stance ; and all the inequalities that are to be found on the sur- face of the present earth, are owing to the accidental confusion into which both earth and waters were then thrown." The next theorist was "Woodward, who, in his Essay towards a Natural History of the Earth, which was only designed to precede a greater work, has endeavoured to give a more rational account of its appearances ; and was, in fact, much better fur- nished for such an undertaking than any of his predecessors, being one of the most assiduous naturalists of his time. His little book, therefore, contains many important facts, relative to natural history, although his system may be weak and groundless. He begins by asserting that all terrene substances are disposed in beds of various natures, lying horizontally one over the other, Bomewhat like the coats of an onion ; that they are replete with shells, and other productions of the sea ; these shells being found in the deepest cavities, and on the tops of the highest mountains. From these observations, which are warranted by experience, he proceeds to observe, that these shells and extraneous fossils are not productions of the earth, but are all actual remains of those animals which they are known to resemble ; that all the beds of the earth lie under each other, in the order of their spe- cific gravity ; and that they are disposed as if they had been left there by subsiding waters. All these assertions he affirms with much earnestness, although daily experience contradicts him in some of them ; particularly we find layers of stone often over the lightest soils, and the softest earth under the hardest bodies. However, having taken it for granted, that all the layers of the earth are found in the order of their specific gravity, the lightest at the top, and the heaviest next the centre, he consequently asserts, and it will not improbably follow, that all the substances ol which the earth is composed, were once in an actual state at THE EARTH. 21 dissolution. This universal dissolution he takes to have hap- pened at tlie time of the flood. He supposes, that at that time a hody of water which was then in the centre of the earth, unit- ing with that which was found on the surface, so far separated the terrene parts as to mix all together in one fluid mass ; the contents of which afterwards sinking according to their respective gra\dties, produced the present appearances of the earth. Being aware, however, of an objection, that fossil substances are not fi3und dissolved, he exempts them from this universal dissolu- tion, and, for that purpose, endeavours to show that the parts of animals have a stronger cohesion than those of minerals ; and that, while even the hardest rocks may be dissolved, bones and shells may still continue entire. So much for Woodward ; but of all the systems which were published respecting the earth's formation, that of WTiiston was most applauded, and most opposed. Nor need we wonder : for being supported with all the parade of deep calculation, it awed the ignorant, and produced the approbation of such as would be thought otherwise ; as it implied a knowledge of abstruse learn, ing, to be even thought capable of comprehending what the writer aimed at. In fact, it is not easy to divest this theory of its mathematical garb : but those who have had leisiure, have found the result of our philosopher's reasoning to be thus : He supposes the earth to have been originally a comet ; and he con- siders the history of the creation, as given us in scripture, to have its commencement jusf when it was, by the hand of the Creator, more regularly placed as a planet in our solar system. Before that time he supposes it to have been a globe without beauty or proportion ; a world in disorder ; subject to all the vicissitudes which comets endure; some of which have been found, at different times, a thousand times hotter than melted iron ; at others, a thousand times colder than ice. These altera, tions of heat and cold, continually melting and freezing the sur- face of the earth, he supposes to have produced, to a certain depth, a chaos entirely resembling that described by the poets, sun-ounding the solid contents of the earth, which still continued nnchanged in the midst, making a great burning globe of more than two thousand leagues in diameter. This surrounding chaos, however was far from being solid : he resembles it to a dense, though flmd atmosphere, composed of substances mingled, 22 HISTORY OF agitated, and shocked against each other j and in this disorder he desciibes the earth to have been just at the eve of creation. But upon its orbit being then changed, when it was more regularly wheeled round the sun, every thing took its proper place ; every part of the surrounding fluid then fell into a situa- tion, in proportion as it was light or heavy. The middle, or central part, which always remained unchanged, still continu ed so, retaining a part of that heat which it received in its primeval J approaches towards the sun; which heat, he calculates, may continue for about six thousand years. Next to this fell the Heavier parts of the chaotic atmosphere, which serve to sustain the lighter: but as in descending they could not entirely be separated from many watery parts, with which they were inti- mately mixed, they drew down a part of these also with them ; and these could not mount again after the surface of the earth was consolidated : they, therefore, surrounded the heavy first- descending parts in the same manner as these surround the cen- tral globe. Thus the entire body of the earth is composed in- ternally of a great burning globe : next which is placed a heavy terrene substance, that encompasses it ; round which is also cir- cumfused a body of water. Upon this body of water, the crust of earth, which we inhabit, is placed : so that, according to him, the globe is composed of a number of coats, or shells, one within the other, all of different densities. The body of the earth being thus formed, the air, which is the lightest substance of all, surrounded its surface ; and the beams of the sun, darting through, produced that light which, we are told, first obeyed the Creator's command. The whole economy of the creation being thus adjusted, it only remained to account for the risings and depressions on the sui'face of the earth, with the other seeming irregularities of its present appearance. The hills and valleys are considered by him as formed by their pressing upon the internal fluid, which sustains the outward shell of earth, with greater or less weight ; those parts of the earth which are heaviest sink into the subja- cent fluid more deeply, and become valleys : those that are lighter rise higher upon the earth's surface, and are called mountains. Such was the face of nature before the deluge : the earth was then more fertile and populous than it is at present ; the life ot man and animals was extended to ten times its present duration j THE EAH.H. 2 J ann all these a>1vantages arose from the superior beat of the central globe, which ever since has been cooling. As its heat was then in full power, the genial principle was also much greater than at present; vegetation and animal increase were carried on with more vigour; and all nature seemed teeming with the seeds of life. But these physical advantages were only Droductive of moral evil ; the warmth which invigorated the body increased the passions and appetites of the mind ; and, as man became more powerful, he grew less innocent. It was found necessary to punish this depravity ; and all living creatures were overwhelmed by the deluge in universal destruction. This deluge, which simple believers are willing to ascribe to a miracle, philosophers have long been desirous to account for by natural causes ; they have proved that the earth could never supply from any reservoir towards its centre, nor the atmosphere by any discharge from above, such a quantity of water as would cover the surface of the globe to a certain depth over the tops of our highest mountains. Where, therefore, was all this water to be found ? Whiston has found enough, and more than a sufficiency, in the tail of a comet ; for he seems to allot comets a very active part in the great operations of nature. He calculates, with great seeming precision, the year, the month, and the day of the week, on which this comet (which has paid the earth some visits since, though at a kinder distance,^ involved our globe in its tail. The tail he supposed to be a vaporous fluid substance, exhaled from the body of the comet by the extreme heat of the sun, and increasing in proportion as it approached that great luminary. It was in this that our globe was involved at the time of the deluge ; and, as the earth still acted by its natural attraction, it drew to itself all the watery vapours which were in the comet's tail ; and the internal waters being also at the same time let loose, in a very short space the tops of the highest mountains were laid under the deep. The punishment of the deluge being thus completed, and all the guilty destroyed, the earth, which had been broken by the eruption of the internal waters, was also enlarged by it ; so that, upon the comet's recess, there was found room sufficient in the internal abyss for the recess of the superfluous waters ; whither they all retired, and left the earth uncovered, but in some re- spects changed, particularly in its figure, which, from being round, 24 HISTOllY OF was now become oblate. In this universal wreck of nature, Noah survived, by a variety of happy causes, to re-people the earth, and to give birth to a race of men slow in believing ill., imagined theories of the earth. After so many theories of the earth which have been publish- ed, applauded, answered, and forgotten, Mr Buifon ventured to add one more to the number. This philosopher was, in every respect, better qualified than any of his predecessors for such aii attempt, being furnished with more materials, having a brightet imagination to find new proofs, and a better style to clothe them in. However, if one so ill qualified as I am may judge, this seems the weakest part of his admirable work ; and I could wish that he had been content with giving us facts instead of systems ; that, instead of being a reasoner, he had contented himself with being merely an historian. He begins his system by making a distinction between the first part of it and the last ; the one being founded only on conjecture, the other depending entirely upon actual observation. The lat- ter part of his theory may, therefore, be true, though the former should be found erroneous. " The planets," says he, " and the earth among the number, might have been formerly (he only offers this as conjecture) a part of the body of the sun, and adherent to its substance. In this situation, a comet falling in upon that great body, might have given it such a shock, and so shaken its whole frame, that some of its particles might have been driven off like streaming sparkles from red-hot iron ; and each of these streams of fire, small as they were in comparison of the sun, might have been large enough to have made an earth as great, nay, many times greater, than our?. So that in this manner the planets, together with the globe which we inhabit, might have been diiven off from the body of the sun by an impulsive force : in this manner also they would continue to recede from it for ever, were they not drav.'n back by its superior power of attraction ; and thus, by the combination of the two motions, they are wheeled round in circles. *' Being in this manner detached at a distance from the body of the sun, the planets, from having been at first globes of liquid fire, gradually became cool. The earth also, having been im- pelled obliquely forward, received a rotatory motion upon its THF EARTH. 25 axis at the very instant of its tormation ; and this motion being greatest at the equator, the parts there acting against the force of gravity, they must have swollen out, and given the earth an oblate or flatted figuie. " As to its internal substance, oiu- globe, having once belong- ed to the sun, it continues to be an uniform mass of melted mat- ter, very probably vitrified in its primeval fusion. But its sur- face is very differently composed. Having been in the beginning heated to a degree equal to, if not greater, than what comets are found to sustain ; like them it had an atmosphere of vapours floating round it, and which, cooling by degrees, condensed and subsided upon its surface. Those vapours formed, according to their different densities, the eaith, the water, and the air ; the heavier parts falling first, and the lighter remaining still suspe.ided." Thus far our philosopher is, at least, as much a system makei as Whiston or Burnet ; and, indeed, he fights his way with great perseverance and ingenuity, through a thousand objections that naturally arise. Having, at last, got upon the earth, he sup- poses himself on firmer groimd, and goes forward mth greater security. Turning his attention to the present appearance of things upon this globe, he pronounces from the view, that the whole earth was at first under water. This water he supposes to have been the lighter parts of its former evaporation, which, while the earthy particles sunk downwards by their natural gra- vity, floated on the surface, and covered it for a considerable space of time. " The surface of the earth," says he,' " must have been in the beginning much less solid than it is at present; and, consequent- ly, the same caures which at this day produce but very slight changes, must then, upon so complying a substance, have had very considerable effects. We have no reason to doubt but that it was then covered with the waters of the sea ; and that those waters were above the tops of our highest mountains ; since, even in such elevated situations, we find shells and other marine productions in very great abundance. It appears also that the sea continued for a consideraI)le time upon the face of the earth: for as these layers of shells are found so very frequent at such l^Theorie de la Terre, vol. i. p. 111. C 26 HISlVftY OF rreat deptbs, and in such prodigious quantities, it seems impos. sible for such numbers to have been supported all alive at one time ; so that they must have been brought there by successive depositions. These shells also are found in the bodies of the liardest rocks, where they could not have been deposited, all at once, at the time of the deluge, or at any such instant revolu- tion ; since that would be to suppose, thai all the rocks in which they are found, were, at that instant, in a state of dissolution, which would be absurd to assert. The sea, therefore, deposited them wheresoever they are now to be found, and that by slow and successive degrees. " It will appear also, that the sea covered the whole earth, from the appearance of its layers, which lying regularly one abovo the other, seem all to resemble the sediment formed at different times by the ocean. Hence, by the irregular force of its waves, and its currents driving the bottom into sand banks, mountains must have been gradually formed within this universal covering of waters ; and these successively raising their heads above its surface, must, in time, have formed the highest ridges of moun- tains upon land, togetherwith continents, islands, andlow grounds, all in their turns. This opinion will receive additional weight by considering, that in those parts of the earth where the power of the ocean is greatest, the inequalities on the surface of the cRith are highest. The ocean's power is greatest at the equa- tor, where its winds and tides are most constant ; and, in fact, the mountains at the equator are found to be higher than in any other part of the world. The sea, therefore, has produced the principal changes in our earth ; rivers, volcanoes, earthquakes, storms, and rain, having made but slight alterations, and only such as have affected the globe to very inconsiderable depths." This is but a veiy slight sketch of Mr Buffon's theory of the earth J a theory vi'hich he has much more powerfully sup- ported, than happily invented ; and it would be needless to take up the reader's time from the pursuit of truth in the discussion of plausibilities. In fact, a thousand questions might be asked this most ingenious philosopher, which he would not find it easy CO answer ; but such is the lot of humanity, that a single Gotli can in one day destroy the fabric which Caesars were employi:'d an age in erecting. We might ask. How moimtains, which .'ne composed (>f the most compact and ponderous substances, should THE EARTir- 27 be the first whose parts the sea began to remove- We might Hsk, How fossil-wood is found deeper even than shells ? which argues, that trees grew upon the places he supposes once to have been covered with the ocean. But we hope this excellent man i's better employed than to think of gratifying the petulance of incredulity, by answering endless objections. • * Since Goldsmith « rote, various other tliecries of the earth have been n-^vanced, the most important of whicli are the Huttonian and WerneriaD. Dr Hutton supposes this globe to be regulated by a system of decay and renovation, and that these are effected by certain processes which bear a uniform relation to each other. The solid matter of the earth, especially the rocks and liigh lands, he supposes to be perpetually separating, by the reite- rated action of air and water, and when thus detached, carried down by the streams and rivers and deposited in the beds of the ocean. From these de- posites, the various strata of our earth are supposed to be formed, obtaining their consolidation from the action of submarine fires ; which being placed at immense depths, must operate on these stratified depositions under the cir- ra;ustance of vast pressure, by wliich volatilization must be prevented, and such changes produced as would not otherwise be effected by the power of heat. The expansive power of subterraneous fire is also called in to explain, by the elevation of strata, their various positions. Thus, whi'ist the ocean is in one part removed by the accumulation and the elevation of strata, fresh receptacles are forming for it in other spots, where new strata will be de- posited, consolidated, and elevated. According to this system, therefore, iu tiie present world — which is made up of the fragments of those which pre- ceded it — the materials are arranging for the formation of a new surface ; new worlds are rising at the bottom of the present oceans ; and imagination pictures successive lands overwhelmed by successive oceans, and these in turn producing new kingdoms, to be peopled by new nations ; the system manifesting, as its author a.'owed, neither vestige of a beginning, nor pros- pect of an end. According to Werner the earth is supposed to have existed originally in a state of aqueous fluidity, which is inferred from its splieroidical form, and from the highest mountains being composed of rocks, possessing a structure exactly resembling that of those fossils, which have, as it were, been formed ynder the eye by wate-. From this circumstance it also follows, that the ocean must have formerly stood very high over these mountains; and as these appear to have been formed during the same period of time, it foUov/s, that the ocean must have formerly covered the whole earth at the same time. Contemplating the formation of the mountains themselves, Werner ditco- vered the strongest proofs of the diminution of tlie original waters of the globe. He ascertained, \st, That the outg-oi/igs—th&t is, the upper cxtrerai. ties as they appear at the surface of the earth— of the newer strata are gene- rally lower than the outgoings of the older, from granite downwards to the alluvial depositc— and that not in particular spots, but around the whole globe. 2d. That the primitive part of the earth is entirely composed of chenii- Ciil precipitations, and that the mechanical depositions only appear in those of a later period, that is, in the transition class ; and continue increaii;ig C 2 28 HlSTOR'i OF CHAP. V. OF FOSSIL- SHELLS, AND OTHER EXTKANEOUS FOSSILS. We may affirm of Mr Buffon, that which has been said at tlie chemists of old; though he may have failed in attaining his through all the succeeding classes of rocks. This evidence of the vast dimi nution of the volume of water which stood so high over the whole earth, is assumed to be perfectly satisfactory, although we can form no correct idea of what has become of it. By the earliest separations from the chaotic nias«. which are discoverable In the crust of the globe, was formed a class of rocks, which are therefore termed primitive rocl;s. The circumstances which mark the high antiquity of these rocks are, that they form the fundamental rock of the other classes. Having been formed in the uninhabitable state of the globe, they contain no petrifactions, and, excepting the small portion which sometimes acctmpany those which will be next mentioned, they contain no mechanical deposites, but are, throughout, pure chemical productions. Small portions of carbonaceous matter, occur only in the newer members of the cla.ss. Before the summits of the mountains appeared above the level of the ocean, and before the creation of vegetables and animals, a rising of the waters is supposed to have taken place, during which, that class of rocks which are said to be of the second formation was deposited The rocks »f this formation are clay, porphyry, pearl stone porphyry, obsidian porphyry, seinite, and pitchstone ; they exhibit very few mechanical depositions, are of complete chemical formation, and contain little or no carbonaceous mat- ter, and never any petrifactions. On the appearance of land, or during the transition of the earth from Its chaotic to its habitable state, rocks whicli from this circumstance are denominated transition rocks were formed. In these rocks, the first slight traces of petrifaction, and of mechanical de- positions, are to be found. As the former class of rocks were purely of che. mical formation, so the contents of these are chiefly chemical productions, mingled with a small proportion of mechanical depositions ; to explain the cause of the mixture, we are referred to the period of their formation, tha at which the summits of the primitive mountains just appeared above the waters, when, by the attraction excited by the motion of the waves, and (vhich we are reminded extended to no great depth, particles of the original mountains were worn oft' and deposited. As the height of the level ot tha ocean diminished, so would the surface on which its waves acted increase, and of course the number of mechanical depositions. Hence, these are much more abundant in the rocks of the next formation, which are denominated fiostx roclxs, (m account of their being generally disposed in horizontal or flat strata. In these, petrifactions are very abundantly found, having beeu formed whilst vegetables and animals existed in great numbers. These rocks are generally of very wide extent, and commonly placed at the foot of primi. tive mountains ; they are seldom of a very great height, from whence it may be inferred, that the water had considerably subsided at the time of theil formation, and did not then cover the whole face of the earth. Countries wimposed of these rocks are not so rugged in their appearance, nor so marked THE EAnXH. 29 principal aiin, of establishing a theory, yet he has brought to- gether such a multitude of facts relative to the history of the earth, and the nature of its fossil productions, that curiosity finds ample compensation, even while it feels the want of con viction. Before, therefore, I enter upon the description of those parts by gndden inequalities, as those in « hich the primitive and transition rock* prevail. Host of the rocks which have been just enumerated, are covered by a great formation, which is named the newest floetz trap. This formation hIso covers many of the highest primitive mountains; it has but little cou. tinuity, but is very widely distributed. It contains considerable quantities of mechanical depositcs, such as clay, sand, and gravel. The remains both f vegetables and animals also occur very abundantly in thi'se deposites. Heaps of trees, and parts of plants, and an abundance of shells and other marine productions, ivitU the horns of stags, and great beds of bituminous fossils, point out the lateness of the period when this formation was deposit- ed, iu tiiis formation several rocks occur wliieli are alio met with in other fliietz formations ; but the following are supposed to be peculiar to this class : basalt, wacke, greystone, porphyry, slate, and trap tuff. These rocks are said to have been formed during the settling of the water consequent upon a vast deluge, which is supposed to have taken place when the surface of the earth was covered with animals and vegetables, and when much dry land ex istej. From various appearances observed in these rocks, it is concluded, Biat the waters in which they were formed, had risen with great rapidity, and had afterwards settled into a state of considerable calmness. The col- lections and deposites derived from the materials of pre-existing masses, worn down by the powerful agency of air and water, and afterwards deposited on tiie land, or on the sea-coast, are termed alluviai, and are of course, of much later formation than any of the preceding classes. These deposites may be divided into : 1st, Those which are formed in mountainous countries, and are found in valleys, being composed of rolled masses, gravel, sand, and some- times loam, fragments of ores, and different kinds of precious stones. 2d, Those wliiuh occur iu low and flat countries, being peat, sand, loam, bog, iron ore, nagelflech, calc-tuff and calc-sinter ; the three latter being better known by the names breccia, tufa, and stalactite. fivery part of the surface of this globe, M. Cuvier maintains, exhibits such phenomena, as unavoidably lead to the conclusion that the sea, at one period or another, has covered the whole, and remained for a long time ifl a state of tranquillity so as to form those regular and extensive horizontal deposites in which many of the marine exuviae are contained. But there are also in. clined or vertical strata of the same nature, situated under the horizontal itrata, which having been necessarily formed in a horizontal position, have been subsequently lifted up and shifted into their inclined or vertii-al situa- eion, and that too before the horizontal strata were deposited above them. Now amid these changes it was hardly possible that the same species of aui. mals should continue to live. There must have been a succession of changes In animal natures corresponding t) that in the chemical properties of the fluid which th<'y inhabited. It is als> conceivable that the change of element might C 3^ 30 insToiiY OF of the earth wluch seem more naturally to fall vvithin the subject, it will not be improper to give a short history of those animiJ productions that are found in such quantites, either upon its sur- face, or at different depths below it. They demand our curiosi- ty ; and, indeed, there is nothing in natural history that has af- forded more scope for doubt, conjecture, and speculation. Whatever depths of the earth we examine, or at whatever dis- tance within land we seek, we most commonly find a number of fossil-shells, which being compared with others from the sea, of knoMT^i kinds, are found to be exactly of a sim.ilar shape and nature.* They are found at the very bottom of quarries and mines, in the retired and inmost parts of the most firm and solid rocks, upon the tops of even the highest hills and mountains, as well as in the valleys and plains ; and this not in one country alone, but in all places where there is any digging for marble, chalk, or any other terrestrial matters, that are so compact as to fence off the external injuries of the air, and thus preserve these shells from decay. These marine substances, so commonly diffused, and so gene- rally to be met with, were for a long time considered by phi- be so great as to cause the entire destruction of all existing genera. Accor. dingly, not only the species, but even the genera change with the strata ; and when the sea last receded from our continent, its inhabitants were not very different from those which it continues to support. The strata around us, therefore, may serve the double purpose of recording the great revolu. tions which have taken place both in the animal kingdom and upon the sur- face of the globe. Neither physical nor astronomical causes of revolution on the earth's surface are sufficient to explain these changes. The irruption of the sea and its retreat have neither been slow nor gradual ; the catastrophes have been sudden, and the present surface of the worUis by no means o/ vc!y ancient formation. This theory approximates more nearly to the Mo. saical record than many others which we have noticed. In fact, modern gfeologists are all eager to bear testimony to the actu.il occurrence of the de. luge ; neither are they, generally speaking, guilty of disowning the act of creation, though some of them have uttered incredible non.sense on this sub. ject. M. Cuvier, indeed, by his catastrophes and epochs, agrees with many scientific men in assigning a far higher .intiqnity to our globe, than is con. eistent with the Mosaic account of the origin of things ; but no Ciiristian will hesitate which to prefer ; and Granville Penn has abundantly demon, strated, what indeed there could be no good reason to doubt, that the objec- tions to the Christaiu Uevelation, founded on the facts of Geology, are a^ un- philosophical as they are impious, I Woodward's Eosay towards a Natural Hiilory, p. Id r THE EAiiXlL 31 losophers as productions, not of the sea, but of the earth. " As we find that spars," said they, "always shoot into peculiar shapes, so these seeming snails, cockles, and mussel-shells, are only gportive forms that nature assumes amongst others of its mineral varieties : they have the shape of fish, indeed, but they have always been terrestrial substances." ' With this plausible solution mankind were for a long time content; but upon closer inquiry, they were obliged to alter their opinion. It was found that these shells had in every re. spect the properties of animal, and not of mineral nature. They were found exactly of the same weight with their fellow shells upon shore. They answered all the chemical trials in the same manner as sea-shells do. Their parts, when dissolved, had the same appearance to \iew, the same smell and taste. They had the same effects in medicine, when inwardly administered ; and, in a word, were so exactly conformable to marine bodies?, that they had all the accidental concretions grooving to them, (such as pearls, corals, and smaller shells,) which are found in shells just gathered on the shore. They were, therefore, from these considerations, given back to the sea; but the wonder was, how to account for their coming so far from their own natural element upon land.^ As this naturally gave rise to many conjectures, it is not to be wondered that some among them have been very extraordi- nary. An ItaKan, quoted by Mr Buffon, supposes them to have been deposited in the earth at the time of the crusades, by the pilgrims who retiuned from Jerusalem; who gathering them upon the sea-shore, in their return carried them to their different places of habitation. But this conjecturer seems to have but a very inadequate idea of their numbers. At Touraine, in France , more than a hundred miles from the sea, there is a plain of abou r nine leagues long, and as many broad, whence the peasants ot the country supply themselves with marl for manuring theu lands. They seldom dig deeper than twenty feet ; and the whole plain is composed of the same materials, which are shells of various kinds, without the smallest portion of earth between them. Here then is a large space, in which are deposited millions of tons of shells, that pilgrims could not have collected, 2 LowtUorp'3 Abridgment, Phil. Trans, vol. ii. p. 433. 3 Woodward, p. 13. 32 HISTORY OP though their whole employment had been nothing else. Englan*! is furnished with its beds, which, though not quite so extensive, yet are equally wonderful. " Near Reading, in Berkshire, for many succeeding generations, a continued body of oyster-shell . has been found through the whole circumference of five or six ncres of ground. The foundation of these shells is a hard locky chalk ; and above this chalk, the oyster-shells lie in a bed vt' green sand, upon a level, as nigh as can possibly be judged, and about two feet thickness."' These shells are in their natu- ral state, but they were found also petrified, and almost in equal abundance^ in all the Alpine rocks, in the Pyrenees, on the hills '){ France, England, and Flanders. Even in all quarries from whence marble is dug, if the rocks be split peipendicularly down- wards, petrified shells and other marine substances will be plainly discerned. " About a quarter of a mile from the river Medway, in the county of Kent, after the taking off the coping of a piece of ground there, the workmen came to a blue marble, which con- tinued for three feet and a half deep, or more, and then beneath appeared a hard floor, or pavement, composed of petrified shells crowded closely together. This layer was about an inch deep, and several yards over ; and it could be walked upon as upon a beach. These stones, of which it was composed, (the describer supposes them to have always been stones,) were either wreathed as snails, or bivalvular like cockles. The wreathed kinds were about the size of a hazel-nut, and were filled with a stony sub- stance of the colour of marl ; and they themselves, also, till they were washed, were of the same colour ; but when cleaned, tliey appeared of the colour of bezoar, and of the same polish. After boiling in water they became whitish, and left a chalkiness upon the fingers." ' In several parts of Asia nd Africa, travellers have observed these shells in great abundance. In the mountains of Castravan, which lie above the city Barut, they quarry out a whita stone, every part of which contains petrified fishes in great numbers, and of surprising diversity. They also seem to continue in such preservation, that their fins, scales, and all the minutest distinc tions of their make, can be perfectly discerned.* 1 Phil. Trans, vol. ii. p. 427. 2 Biiffou, vol. i. p. 407. 3 PJul Trans, p. 126. 4 Bufiuu, vol. i. p. UU THK EAETH. 33 From all these instances we may conclude, that fossils are vny numerous : asd, indeed, independent of their situation, they afTord no small entertainment to observe them as preserved in the cabinets of the curious. The varieties of their kinds are astonishing. Most of the sea-shells which are known, and many others to which we are entirely strangers, are to be seen either in their natural state, or in various degrees of petrifaction.' In the place of some we have mere spar, or stone, exactly express- ing all the lineaments of animals, as having been wholly formed Irom them. For it has happened, that the shells dissolving by very slow degrees, and the matter having nicely and exactly filled all the cavities within, this matter, after the shells have perished, has preserved exactly and regularly the whole print of their in- ternal surface. Of these there are various kinds found in our pits ; many of them resembling those of our own shores ; and many others that are only to be found on the coasts of other countries. There are some shells resembling those that are never stranded upon our coasts j' but always remain in the deep ;' and many more there are which we can assimilate with no shells that are known amongst us. But we find not only shells in our pits, but also fishes and corals in great abundance ; together with almost every sort of marine production. It is extraordinary enough, however, that the common red coral, though so very frequent at sea, is scarcely seen in the fossil world ; nor is there any account of its having ever been met with. But to compensate for this, there are all the kinds of the white coral now kno\\Ti, and many other kinds of that substance with which we are unacquainted. Of animals there are various parts : the vertebrae of whales, and the mouths of lesser fishes ; these, with teeth also of various kinds, are found in the cabinets of the curious ; where they receive long Greek names, which it is neither the intention nor the province of this work to enu- merate. Indeed, few readers would think themselves much im- proved, should I proceed with enumerating the various classes of the Conicthyodontes, Polyleptoginglimi, or the Orthoceratites. These names, which mean no great matter when they are ex- phiined, may serve to guide in the furnishing a cabinet ; but they are of very little service in furnishing the page of instruotiva history. I Hill, p. 646. 2 LiftoralcB. 3 PflagfiL SI' msrcAY OF From all these instances we see in what abundance petrifac tions are to be found ; and, indeed, Mr Buffon, to whose ac- counts we have added some, has not been sparing in the variety of his quotations, concerning the places where they are mostly to be found. * However, I am siuprised that he should have * Mr Kirwan remarks, that petrifactions are most commonly found in ftiata of marie, chalk, limestone, or day ; seldom in sand-stone, still mure larely in gypsum, &c. Tliey sometimes occur among' ores, and almost always consist of the species of earth, stone, or other mineral, which immediately surrounds them. Those of shells are generally found nearest the surface o! the earth, those of fish deeper, and those of wood deepest. A very remark- able circumstunce is, that petrifactions are found in climates where their originals could not liave existed. From the gradual and insensible concre- tion of this kind of matter from dropping waters, are found the large pendu- lous columns, hanging like icicles from the roofs and sides of caves. The most remarkable are in the Peak of Derbyshire. Sometimes they are found in the arches of old bridges, and arise from water oozing through, and carry, ing particles of lime with it. Petrifactions occur in three states ; some- times they are a little altered; sometimes they are converted into stone; and sometimes only the impressions of them, or the moulds in which they have been enclosed, remain. Wood occurs in great abundance in many parts of England, buried at various depths under the surface, and very little altered either in its texture or properties. Pit-coal is supposed to be of vegetable origin. One circumstance confirms this opinion, namely, the existence of vast depositions of matter, half-way, as it were, between perfect wood and perfect pit-coal; betraying obviously its vegetable nature, and yet so nearly approximating to pit-coal in several respects, that it lias been generally distinguished by the name of coal. No complete treatise on geological botany has hitherto appeared in this country. Mr Parkinson's first volume, it is true, is dedicated to the consi. deration of the vegetable kingdom. It contains descriptions and beautiful figures of many varieties of fossil wood, plants, flowers, seeds, and fruits, from various parts of Europe, and treats of the mineral and petrifying pro. cesses to which they have been subjected. But at the period this writer commenced his labours, no systematic classification or nomenclature had been formed, nor was it known that this class of fossils was so numerous. The preat source whence our geologists have hitherto drawn their knowledge of antediluvian plants, is the splendid work, the Flora der Vorwelt of Count Sternberg. In England the coal formations are particularly rich in beaud- fully preserved plants. So far as they admit of comparison, they approach those tribes of plants which now exist in warm climates, and luxuriate in moist situations. They consist chiefly of palms and arborescent ferns, fScv Plate I, fig. 1,; succulent plants, cacti, euphorbiae, canes, reeds, and gramina The trunks or stems thus discovered, belong principally to arundinaoeou* plants, approximating to those now known, partly to the palmaceous order, and partly to anomalous forms, constituting a transition between these and the coniferous plants. From the few comparisons which have been hitherto Instituted between the plants of various distant coal fields, there is reason to conclude that they have a general resemblance in all parts of the world : and. T,H£ KAItlH. OJ omitted the mention of one, whirh, in some measure, more than any of the rest, would have served to strengthen his theory. We are informed, by almost every traveller' that has described the pyramids of Egypt, that one of them is entirely built of a If so, it contributes to establish a fact, on which much specniation has bcpn employed, of the original uniformity of climate at those remote points on tha earth's surface, lu plate I, other representations of fossils may be seen. Fig. 2 represents the impressioa of leaves, on sand-stone, of a pale yt'lluw colour. In this specimen a circumstance is observable which is highly deserv- ing observation. Lhwydd and others remark, that sometimes, though rarely, the leaf will be found so well preserved, that even the colour may ba discerned : and in this specimen the leaves are evidently of a very dark olive green. Fig. 3 represents an asterial fossil fiom America, apparently of the nature of the Encrinus. Fig. 4 represents the Lily Encrinite, with part of its vertebral column attached to it Accumulations of trees, called "subterranean forests," may be traced a iotervals, along our eastern coasts. Some of them, apparently, are the ra mains of forests which clothed the surface of our soil prior to the last grea geological epoch. Most of the trees of this class, although broken off, over, whelmed by tremendous violence, and often flattened by the pressure of di- luvial and alluvial deposits, appear to occupy their original sites; their stumps still remain rooted in the soil on which they evidently once flourished. These lignites have been much confounded with others of obvious postdilu. vian lacustrine origin. Mosses, conferva;, and other equally delicate vege. table substances, preserved in agate and chalcedony, have been examined by Dr MacCulloch, who is inclined to refer their origin to a period nei;r!y coeval with the earliest existence of organic matter. Naturalists have often failed in their endeavours to identify the antediluvian plants with those now existing. They evidently flourished under a warm climate; but botanists hesitate to pronounce upon the species, or even the genera. In one instance, lately, a fossil plant has been determined with unusual precision. Under the name Trichomanes rotundatus, Mr Lindley has described a vegetable, discov. ered within a nodule of argillaceous ironstone, which plant he does not hesi- tate to identify closely with one which is now only known recent in the deep forests of New Zealand. Zoophytes, which form the link between vegetables and shellfish, are little less obscure than th 5 plants ; and we are again struck with the want of agreement between the organic productions of the ancient and of the present world. As far as the investigation has been pursued, it would seem that the loophytes of those remote and mysterious times were not less numerous . ;iad beautiful than those of our own days. Mr Parkinson examined K (• fossil corals, and found nearly the whole differed from any that are no w known. " In my attempt," says tliis able observer, "to preserve a paralell between the recent and the fossil species, I have been,most completely foiled. Indeed, so little could this parallel be preserved, that I am under the neces- sity of acknowledging I am not certain of the existence of tne recent ana- logue of any one mineralised coral." When the ihellfish that inhabit our ocean are compared with the fosse 2 Hasselqnist, Sandys. 36 msTOHv OF kind of free-stone, in which these petrified shells are found m great abundance. This being the case, it may be conjectured, as we have accounts of these pyramids among the earliest records of mankind, and of their being built so long before the age of tribes, essential specific differences are perceived ; and these differences become more striking as we recede from the latest formations. lo our cra^ and fresli-water beds some species may be discovered which possess a (strong similarity, if not absolute identity, with those living in our lakes and seas. Even here, the identity is maintained but by a limit- ed number, which are intermixed with numerous others that have no recent analogues. Investigations in fossil conchology lead, therefore, to one result ; that, with the inconsiderable exceptions that have been stat- ed, the species have not been perpetuated to our times. One of the most remarkable facts elicited is, that certain Testacea, whose genera were abundantly preserved and prolonged through so many forma- tions, should now exist so sparingly, or be entirely lost. We might instance the TerebratulsB, which abound no less in the mountain limestone than in the chalk, and in almost every intermediate rock, which are absent in nearly every one of our tertiary beds, and re-appear in the most recent. Not less than 100 fossil species of Terebratulae, and myriads of individuals, are known to us ; but the recent shells of this genus are comparatively few. Of Tri. g'onia, also, 25 species are found in our strata, often abundantly, and termina- ting, like the Ammonites, with the chalk. Until lately, thi.s genus was considered to be extinct; but one species has been discovered on the shores of New Holland. Of Ammonites, so profusely distributed, whose species amount, it is said, to no less than 200, and of which about 175 are known iu the English formations, none now remain. 29 species of Products, 3 of Pen. tameriis, and 19 of Spirifer, inhabited the waters that produced the transi- tion and mountain limestone, and contiguous shales ; but these genera are altogether extinct. Indeed, almost the whole series of antediluvian nuilti. locular shells seem to have shared a similar fate. On the other hand, instan- ces are no less abundant and striking, where the recent species comprehend- ed under certain genera do greatly outnumber the fossils. Thus, under the liinnean genus Conus are comprised 155 species existing ; but only 3 occur fossil in our London clay. The genus Cypraea contains about 110 living species, and only four fossil in the tertiary beds. Thus, during the revolu- tions of ages, some races have been extinguished, and have given place to others which may still be traced in our seas. In the great tertiary deposits of the Sub-Apenninea, Brocchi conceived he could point out some marine Bhells, which are now very widely dispersed, in the Indian and American Oceans, the Atlantic, the Red Sea, the Persian Gulf, and the coasts of Africa and Jamacia. When we consider the enormous proportion of insects to the rest of tlie animated beings in the present world, — being, according to Baron Humboldt, no less than 44,000 out of 51,700, — we might expect to discover morn fre- quent traces of these tribes in the fossil world. Whether they did not pro- vail in such numbers during the former period of the globe, or whether, aa is most probable, the extreme delicacy of theii- structure was unfavourable to their preservation, we have only the fact, that but scanty traces of their former existence, particularly in the elder beds, do now appear. Tilt: EARTH. 37 Herodotus, who lived but fifteen hundred years after the flooil, vhat even the Egyptian priests could tell neither the time nor the cause of their erection; I say, it maybe conjectured that they were erected but a short time after the flood. It is not Of Birds the remains also are of rare occurrence ; and the same re. mark might be applied to them, with respect to proportion, as to the preced- in g^ order. It does seem a singular circumstance, that more birds have not heen found fossil, when we consider that they now are, as regards species, -five times as numerous as the Mammalia. Of Fishes, the most common form in which they are found is compressed between the laminge of sandstones, schists, calcareous slates, and Purbeck marble. Their teeth, scales, and vertebrae are abundant in many formations between the has and London clay, particularly in the latter, and are even yet more plentiful in the Suffolk crag beds. These teeth are commonly as. cribed to varieties of sharks. Palates, or " denies molares," are found in the oolites, and are beautifully preserved in chalk. A vast collection of irapres- eions (if fish have long been known to exist in the calcareous schist of Monte Bolca, many of which have been identified with living species. In M. Bozza's collection, out of 100 known fishes, 4 were ascertained to be similar to those living in the seas of Otaheite. In the Pans museum, containing 62 species, 23 are said to be common to Furopean seas ; 14 to Indian seas ; 2 to African ; 13 to South American ; and 5 to North American. In another collection, of 103 species, from the same place, M. Saussure decided that 34 resemble those of European seas ; 39 Asiatic; 3 African; 18 South Ameri. can; 11 North American. Of oviparous quadrupeds (amphibia,) several genera are now known in different formations ; but it does not appear that the fossil skeletons of these animals assimilate precisely to living species. By far the greater number are of extraordinary conformation. Thus, the Plesiosaurus {See Plate II. why, therefore, may we not as well ascribe the production of all to fresh waters, where we do not find them as we do that of the latter to the sea only, where we in diluvial or tertiary beds. We are therefore led to unite in the opinion that he is among "the most recent tenants of the globe," coincident witii the oldest records and traditions of liis race ; and that the time in which he lias inhabited the earth forms but a trifling portion of its absolute duration. Whether man was coeval with the mastodons, the mammoths, and othev mighty animals that once ranged the earth, and left their traces on so large a part of its surface, is an inquiry which there seems little probability will ever be solved. At present we have only the negative fact, that no human remains have been discovered of equal antiquity with those extinct race* of aniinals of which we have made brief mention in this imperfect sketch. 1 Hill's Fossils, p. 41, THE EARTH. 41 never find them? We know that lakes, and lands also, h;iv« produced animals that are now no longer existing ; why, there- fore, might not these fossil productions be among the number? I grant that this is making a very harsh supposition ; but I can- not avoid tliinking that it is not attended with so many embar- rassments as some of the former, and that it is much easier to believe that these shells were bred in fresh water, than thut the sea had for a long time covered the tops of the highest mountains. CHAP. VI. OF THE INTERNAL STRUCTURE OF THE EARTH. Having, in some measure, got free from the regions of con- jecture, let us now proceed to a description of the earfh as we find it by examination, and observe its intenial composition, as tar as it has been the subject of experience, or exposed to human inquiry. These inquiries, indeed, have been carried but to a verv Jittle depth below its surface, and even in that disquisition men have been conducted more by motives of avarice than of curiosit)'. The deepest mine, which is that at Cotteberg in Hungary,' reaches not more than three thousand feet deep ; but what pro- portion does that bear to the depth of the terrestrial globe, down to the centre, which is above four thousand miles? All, there- fore, that has been said of the earth, to a deeper degree, is merely fabulous 'ir conjectural : we may suppose, with one, thai it is a globe of glass ;' with another, a sphere of heated iron ;* with a third, a great mass of waters;* and with a fourth, one dreadful volcano :' but let us at the same time show our con- Bciousness, that all these are but suppositions. Upon examining the earth, where it has been opened to any depth, the first thing that occurs, is the different layers or beda of which it is composed ; these all lying horizontally one over tlic other, like the leaves of a book, and each of them composed 8 Boyle, vol. iii p. 210. 3 BufTon. 4 WhUton. 6 Buri.et. 6 l-'xc! cr. 4 2 HISTORY OF of materials that increase in weight, in proportion as they lie deeper. This is, in general, the disposition of the diiferent materials, where the earth seems to have remained unmolested ; but this order is frequently inverted ; and we cannot tell whether from its original formation, or from accidental causes. Of dif- ferent substances, thus disposed, the far greatest part of our globe consists, from its siu"face downwards to the greatest depths we ever dig or mine.' The first layer most commonly found at the surface, is that light coat of blackish mould, which is called by some garden tarlh. With this the earth is every where invested, unless it be washed oif by rabis, or removed by some other external vio- lence. This seems to have been formed from animal and vege- table bodies decaying, and thus turning into its substance. It also serves again as a storehouse, from whence animal and vege- table nature are renewed : and thus are all vital blessings con- tinued with unceasing circulation. This earth, however, is not to be supposed entirely pure, but is mixed with much stony and gravelly matter, from the layers lying immediately beneath it. It generally happens, that the soil is fertile in proportion to the quantity that this putiified mould bears to the gravelly mixture ; and as the former predominates, so far is the vegetation upon it more luxuriant. It is .this external covering that supplies man with all the true riches he enjoys. He may bring up gold and jewels from greater depths ; but they are merely the toys of a capricious being, things upon which he has placed an imaginary value, and for which fools alone part with the more substantial blessings of life. " It is this earth," says Piiny,^ " that, like a kind mother, receives us at our birth, and sustains us when bom." It is this alone of all the elements around us, that is never found an enemy to man. The body of waters deluge him with rains, oppress him mth hail, and drown him with inundations. The air rushes in storms, prepares the tempest, or lights up the Volcano ; but the earth, gentle and indulgent, ever subservient to the wants of man, spreads his walks with flowers, and his table with plenty ; returns with interest every good committed to her care ; and though sl)e produces the poison, she still sup- plies the antidote ; though constantly teased more to furnish the I Woodward, p. 0. 2 Plinii Histo-ia Naturalis, lib. ii. cap. 63. THE EARTH. 43 luxuries of man than his necessities, yet even to the last, she continues her kind indulgence, and when life is over, she piously covers his remains in her bosom. This external and fruitful layer which covers the earth, is, as was said, in a state of continual change. Vegetables, which are naturally fixed and rooted to the same place, receive their adventitious noxuishment from the surrounding earth and water ; animals, which change from place to place, are supported by these, or by each other. Both, however, having for a time enjoyed a life adapted to their nature, give back to the earth those spoils, which they bad borrowed for a very short space, yet still to be quickened again into fresh existence. But the deposits they make are of very dissimilar kinds, and the earth is very differently enriched by their continuance : those countries that have for a long time supported men and other animals, having been ob- served to become every day more barren ; while, on the contraiy, those desolate places, in which vegetables only are abundantly produced, are known to be possessed of amazing fertility. " In regions which are uninhabited," ^ says Sir Buffon, " where the forests are not cut down, and where animals do not feed upon the plants, the bed of vegetable earth is constantly increasing. In all woods, and even in those which are often cut, there is a layer of earth of six or eight inches thick, which has been formed by the leaves, branches, and bark, which fall and rot upon the ground. I have frequently observed on a Roman way, which crosses Burgundy, for a long extent, that there is a bed of black earth, of more than a foot thick, gathered over the stony pavement, on which several trees, of a very considerable size, are supported. This I have found to be nothing else than an earth formed by decayed leaves and branches, which have been converted by time into a black soil. Now as vegetables draw much more of their nourishment from the air and water than they do from the earth, it must follow that in rotting upon the ground, they must give more to the soil than they have taken from it. Hence, therefore, in woods kept a long time without cutting, the soil below increases to a considerable depth; and such we actually find the soil in those American H'ilds, where the forests have been undisturbed for ages. But 3 Buffon, vol. i. p. 35a 1i HISTOPvY or it is otherwise where men and animals have long subsisted : for Hs they make a considerable consumption of wood and plants, both for firing and other uses, they take more from the earth than they return to it ; it follows, therefore, that the bed of ve- getable earth, in an inhabited country, must be always diminish- ing ; and must at length resemble the soil of Arabia Petrea, and other provinces of the East, which having been long inhabited, are now become plains of salt and sand ; the fixed salt always remaining, while the other volatile parts have flown away. " If from this external surface we descend deeper, and view the earth cut perpendicularly downwards, either in the banks of great rivers, or steepy sea shores, or going still deeper, if we ob- serve it in quarries or mines, we shall find its layers regularly disposed in their proper order. We must not expect, however, to find them of the same kind or thickness in every place, as they differ in different soils or situations. Sometimes marl is seen to be over sand, and sometimes under it. The most com- mon disposition is, that under the first earth is found gravel or sand, then clay or marl, then chalk or coal, marbles, ores, sands, gravels ; and thus an alteration of these substances, each grow- ing more dense as it sinks deeper. The clay, for instance, found at the depth of a hundred feet, is usually more heavy than that found not far from the surface. In a well which was dug at Amsterdam, to the depth of two hundred and thirty feet, the following substances wer ound in succession :' seven feet of vegetable earth, nine of turf, nine of soft clay, eight of sand, four of earth, ten of clay, four of earth, ten of sand, two of clay, four of white sand, one of soft earth, fourteen of sand, eight of clay mixed with sand, four of sea-sand mixed with shells, then a hundred and two feet of soft clay, and then thirty-one feet of sand. In a well dug at Marly, to the depth of a hundred feet, Mr Kuffon gives us a still more exact enumeration of its layers of earth. " Thirteen of a reddish gravel, two of gravel mingled with a ^atrifiable sand, three of mud or slime, two of marl, four of marly stone, five of marl in dust mixed with vitrifiable sand, six of very fine vitrifiable sand, three of earthy marl, three of hard marl, one of gravel, one of eglantine, a stone of the h;i\ii- 1 Va'PuiuE, as (jiintfJ by Mr Euffon, p. 3.ia THE EAllTH. 45 ness and grain of marble, one of gravelly marl, one of stony marl, one of a coarser kind of stony marl, two of a coarser kind still, one of vitrifiable sand mixed with fossil-shells, two of fine gravel, three of stony marl, one of coarse powdered marl, one of stone caleinable like marble, three of gray sand, two of white sand- one of red sand streaked with white, eight of gray sand with shells, three of very fine sand, three of a hai"d gray stone, four of red sand streaked with white, three of white sand, and fifteen of reddish \-itrifiable sand. " In this manner the earth is every where found in beds over beds ; and, what is still remarkable, each of them, as far as it extends, always maintains exactly the same thickness. It is fomid also, that as we proceed to considerable depths, eveiy layer grows thicker. Thus in the adduced instances we might have observed, that the last layer was fifteen feet thick, while most of the others were not above eight ; and this might have gone much deeper, for aught we can tell, as before they got through it the workmen ceased digging. These layers are sometimes very extensive, and often are found to spread over a space of some leagues in circumference. But it must not be supposed that they are uniformly continued over the whole globe without any interrupti'^n ; on the contrary, they are ever at small intervals, cracked through as it were by perpendicular fissures : the earth resembling, in thi.» respect, the muddy bottom of a pond, from whence the water has been dried off by the sun, and thus gaping in several chinks, which descend in a direction perpendicular to its surface. These fissures are many times found empty, but oftener closed up with adventiti- ous substances, that the rain, or some other accidental causes, have conveyed to fill their cavities. Their openings are not less different than their contents, some being not above half an inch wide, some a foot, and some several hundred yards asunder. Which last form those dreadful chasms that are to be found in the Alps, at the edge of which the traveller stands dreading to look down at the immeasurable gulph below. These amazing clefts are well known to such as have passed these mountains, where a chasm frequently presents itself several hundred feet deep, and as many over, at the edge of which the way lies. It often happens also, that the road leads along the bottom, and ihen the spectator observes on each side friphtful precipices 46 HiSTOKY OF several hundred yards above him ; the sides of which correspond so exactly with each other, they evidently seem torn asunder. But these chasms, to be found in the Alps, are nothing to what O vale tells us are to be seen in the An des. These amazing moun- tains, in comparison of which the former are but little hills, have theii' fissures in proportion to theirgreatness. In some places they are a mile vnde, and deep in proportion ; and there are some others, that, running under ground, in extent resemble a province. Of this kind also is that cavern called Eldenkole, in Derby- shire, which Dt Plott tells us, was sounded by a line of eight and twenty hundred feet, without finding the bottom or meeting with water : and yet the mouth at the top is not above forty yards over.' This immeasiu-able cavern runs perpendicu- larly downward ; and the sides of it seem to tally so plainly as to show that they were once united. Those who come to visit the place, generally procure stones to be thrown into its mouth ; and these are heard for several miimtes, falling and striking against the sides of the cavern, producing a sound that resembles distant thunder, dying away as the stone goes deeper.* Of this kind also is that dreadful cavern described by Elian j his account of which the reader may not have met with.^ " In the country of the Arrian Indians, is to be seen an amazing chasm, which is called, The Gulph of Pluto. The depth and the re- cesses of this horrid place are as extensive as they are un- known. Neither the natives, nor the curious who visit it, are able to tell how it was first made, or to what depths it descends. The Indians continually drive thither great multitudes of ani- mals, more than three thousand at a time, of different kinds, sheep, horses, and goats ; and, with an absurd superstition, force them into the cavity, from whence they never return. Their several sounds, however, are heard as they descend j the bleating of sheep, the lowing of oxen, and the neighing of horses, issuing 1 Phil. Trans, vol. iL 370. * Dr Plott has exaggerated the width and depth of this fearful cavern. Mr Lloyd, who de.scended into it, found its depth to be 186 feet. Its mr)ulh is 20 feet wide one way, and fifty another. He found it tu consist of two compartments, the first was in shape like an oven, the other resembled the dome of a glass-house furnace. Mr Lloyd says, from its roof were hanging stalactites, from wliich circumstance we may conclude, that it occurs in n Sine-stone rock. 2 ^liani Var. Hist. lib. xvi. cap. !G- THE liAUTH. 4>7 tip to the raouth of the cavern. Nor do these souikIs cease, iis the place is continually furnished with a fresh supply." There are many more of these dreadful perpendicidar fissures m different parts of the earth ; wdth accounts of which, Kircher, Gaffarellus, and others who have given histories of the wonders of the subterranean world, abundantly supply us. The gener- ality of readers, however, will consider them with less astonish- ment when they are informed of their being common all over the earth ; that in every field, and every quarry, these, perpendicular -fissures are to be found, either still gaping, or filled %vith matter that has accidently closed their interstices. The inattentive spectator neglects the inquiry, but their being' common is partly the cause that excites the philosopher's attention to them : the irregularities of nature he is often content to let pass unexamin- ed ; but when a constant and a common appearance presents it- self, every return of the object is a fresh call to his curiosity; and the chink in the next quarry becomes as great a matter of wonder as the chasm in Eldenhole. Philosophers have long, therefore, endeavoured to find out the cause of these perpendi- cular fissures, which our own countrymen, Woodward and Ray, were the first that found to be so common and universal. Mr Buflfon supposes them to be cracks made by the sun, in drying up the earth, immediately after its immersion from the deep. The heat of the sun is very probably a piincipal cause ; but it is not right to ascribe to one only, what we find may be the result of many. Earthquakes, severe frosts, bursting waters, and storms tearing up the roots of trees, have, in our own times, produced them ; and to this variety of causes we must, at present, be content to assign those that have happened before we had opportunities for observation. CHAP. VIL Of CAVES AND SUBTERaANEOUS PASSAGES THAT SI>fK, BUT NOT rERPENDICULAULY, INTO THE EARTH. In surveying the subterranean wonders of the globe, besides iLuie fissures that descend perpendicularly, we frequently fii.d 48 HISTOllY OF Others that descend but a little way, and then spread theniseivca often to a great extent below the surface. Many of these caverns, it must be confessed, may be the production of an and human industry ; retreats made to protect the oppressed, or shelter the spoiler. The famous labyrinth of Candia, for in- stance, is supposed to be entirely the work of art. Mr Tourne- fort assures us, that it bears the impression of human industry and that great pains have been bestowed upon its formation. The stone-quarry of Maestricht is evidently made by labour ; carts enter at its mouth, and load within, then return, and dis- charge their freight into boats that lie on the brink of the river Maese. This quarry is so large, that forty thousand people may take shelter in it : and it in general serves for this purpose, when armies march that way ; becoming then an impregnable retreat to the people that live thereabout Nothing can be more beautiful than this cavern, when lighted up with torches : for there are thousands of square pillars, in large level walks, about twenty feet high ; and all wrought with much neatness and regularity. In this vast grotto there is very little rubbish ; which shows both the goodness of the stone and the carefulness of the workmen. To add to its beauty, there also are in various parts of it, little pools of water, for the convenience of the men and cattle. It is remarkable also, that no droppings are seen to fall from the roof, nor are the walks any way wet under foot, except in cases of great rains, where the water gets in by the air shafts. The salt mines in Poland are still more spacious than these. Some of the catacombs, both in Egypt and Italy, are said to be very extensive. But no part of the world has a greater number of artificial caverns than Spain, which were made to serve as retreats to the Christians against the fury of the Moors, when the latter conquered that country. However, an account of the works of art does not properly belong to a na- tuial histor)'. It will be enough to observe, that though caverns be found in every country, far the greatest part of them have been fashioned by the hand of nature only. Their size is found beyond the power of man to have effected, and their forms but ill adapted to the conveniences of a human habitation, in some places indeed, we find mankind still make use of th.ena 1 Plijl. TrauB. Tol. ii. p. 363. THE EARTH. 49 IS houses ; particularly in those countnes where the climate is veiy severe;* but in general they are deserted by every race of meaner animals, except the bat : these nocturnal solitary creatures are usually the only inhabitants ; and these only in such whose de. scent is sloping, or, at least, not directly perpendicular. There is scarcely a country in the world without its natural caverns ; and many new ones are discovered every day. Of those in England, Oakey-hole, the Devil's-hole, and Penpark- hole, have been often described. The former, which lies on the «outh side of Mendip-hills,' within a mile of the town of Wells, IS much resorted to by travellers. To conceive a just idea of this, we must imagine a precipice of more than a hundi'ed yards high, on the side of a mountain whi«h shelves away a mile above it. In this is an opening not very large, into which you enter, going along upon a rocky uneven pavement, sometimes ascend- ing, and sometimes descending. The roof of it, as you advance, grows higher ; and in some places is fifty feet from the floor. In some places, however, it is so low that a man must stoop to pass. It extends itself, in length, about two hundred yards : and from every part of the roof and the floor, there are formed sparrj' concretions of various figures, that by strong imaginations have been likened to men, lions, and organs. At the farthest part of this cavern rises a stream of water, well stored \vith fish, large enough to turn a mill, and which discharges itself near the entrance. Penpark-hole, in Gloucestershire, is almost as remarkable as the former. Captain Stiormy descended into this by a rope, twenty-five fathoms perpendicular, and at the bottom found a very large vault in the shape of a horse-shoe. The floors con sisted of a kind of white stone enamelled with lead ore, and the pendant rocks were glazed with spar. Walking forward on this stony pavement, for some time, he came to a great river, twenty fathoms broad, and eight fathoms deep ; and having been in- formed that it ebbed and flowed with the sea, he remained in this gloomy abode for five hours to make an exact observation. He did not find, however, any alteration whatsoever in its appear, ance. But his curiosity was ill requited ; for it cost this un- fortimate gentleman his life ; immediately after his return he 2 Phil. Trans, vol. ii. p. 368. 3 Ibid. £ 50 HISTORY Of was seized with an unusual and violent head-ache, which threw him into a fever, of which he died soon after.* But of all the subterranean caverns now known, the grotto of Antiparos is the most remarkable, as well for its extent as fo • There are other caves in Great Britain, fully as remarkable as those abova described. — Donnald Mill-hole, five miles N. K from Lancaster^ is a cavern in the middle of a large common : the traveller is led to it by a large brook, nearly as big- as the New River of London, which, after turning a corn-mill, just at the entrance of the cave, runs in at its mouth by several cascades, continuing its course two miles under a large mountain ; and at last makes its appearance again near Cranford, a village in the road to Kendal. The en. trance of this subterraneous channel has something most pleasantly horrible in it : from the mill at the top you descend for about ten yards perpendicular, by means of chinks in the rocks, and shrubs or trees ; the road is then al. most parallel to the horizon, leading to the right a little winding, till you have some hundreds of yards tliick of rocks and minerals above you. In this manner we proceed, sometimes through vaults so capacious that we can- not see either roof or sides, and sometimes we have to crawl on our hands and feet, from its narrowness ; still following the brook, which has a con. tinned murmiu-ing harmony well suited to the place ; for the different heights of its falls are so many keys of music, which is all conveyed to the ear by the amazing echo, and adds greatly to the majestic horror which surrounds us. The beautiful lakes formed by the brook, in the hollow parts of the cavern, realize the fabulous river Styx, so famous in heathen mythology. The falls from one rock to another break the rays of the candles of those who explore this cavern, in such a way, that they form most curious vibrations and ap- pearances upon the variegated roof. The sides, too, are not less remarkable for fine colouring ; the damps, the creeping vegetables, and the seams in the marble and limestone part of the rocks, make as many tints as are seen in the rainbow, and are covered with a perpetual varnish from the just weeping springs that trickle from the roof. The curious in grottos and cascades will be much gratified by exploring this wonderful place. Pooler-hole is within a mile of Buxton : tlie entrance into this hole is so narrow, that you most stoop to get in : but it soon widens to a broad and li.fty cavity, which extends in height upwards of a quarter of a mile. Water drops from the roof every where, and by the reflection of the candles, which !he guides carry, exhibit a thousand imaginary figures, as lions, fonts, lan- terns, organs, flitches of bacon, &c. At the farther end of this cavity is Mary queen of Scots' pillar, so named after her paying this place a visit ; and this is the boundary of most people's curiosity who visit this place. A stream of water runs through the middle of this cavern, with a liideous noise re-echoed from all sides. On the left hand side, you see, after creeping through a passage of ten yards long, a chamber, where they say Poole, a fii- mous robber, lived, from wliich circumstance the place is named, 7'lie Dropping C.ive at Slams, on the east coast of Buchan, in Aberdeen. Bhire, extends upwards of 200 feet under ground ; numerous drops of watef ooze through the roof, passing through abed of lime, with which they ara impregnated, and form fantastic incrustations or stalactites. Great (juauU. THE KAlxTH. 51 tlie beauty of its sparry incrustations. This celebrated caveni was first discovered by one Magni, an Italian traveller, about a hundred years ago, at Antiparos, an inconsiderable island of the Archipelago.' The account he gives of it is long and in- ties of these have been cut out, and burnt for lime ; in consequence of which the caye is disfigared and nearly destroyed. In the island of Stafl'a, one of the Hebrides, on tlie north west coast ot Scotland, is another striking object of natural history, perhaps the most mag^nificent of the kind in existence. It is thus described by Sir Joseph Banlcs, in a communication to Mr Pennant. " We were no sooner arrived," says Sir Joseph, " than we were struck with a scene of mag- nificence which exceeded our expectations, though founded, as we thought, on the most sanguine foundations. The whole of that island, a mile in length, and half a mile in breadth, supported by ranges of natural pillars, mostly above fifty feet high, every stone being formed into a certain num- ber of sides and angles, standing in natural colonnades, according as the bays or points of land formed themselves : upon a firm basis of solid unform- ed rock, above these the stratum which reaches to the soil or surface of the is- land, varied in thickness as the island itself is formed into hills or valleys ; each hill, which hung over the columns below, forming an ample pediment ; some of these above sixty feet in thickness, from the base to the point, formed by the sloping of the hill on one side almost in the shape of those used in archi- tectiu^e. Compared with tlus, what are the cathedrals onpalaces built by man ? Mere models or playthings!: imitations as diminutive as his works will always be, when compared to those of nature. Where is now the boast'of the architect ? Regularity, the only part in which he fancied himself to exceed his mistress, Kature, is here found in her possession; and herei t has been for ages undescribed. Is not this the school where the art was originally studied ? and what has been added to this by the whole Grecian school ? A capital to ornament the column of nature, of which they could expect only a model ; and for that very capital they were obliged to a bush of Acanthus : how amply does na. ture repay those who study her wonderful works ! With our minds full of such reflections, we proceeded along the shore, treading upon another Giant's Causeway, every stone being regularly formed into a certain number of sides and angles, till in a short time we arrive at the mouth of a cave, the most magnificent, I suppose, that has ever been described by travellers. The mind can hardly fo' ra an idea more magnificent than such a space supported on each side by ranges of columns, and roofed by the bottoms of those which have been broke off in order to form it ; between the angles of which a yeU low stalagraitic matter has been exuded, which serves to define the angles precisely, and at the same time vary the colour with a great deal of elegance ; and to render it still more agreeable, the whole is lighted from without, so that the farthest extremity is very plainly seen from without ; and the airi being agitated by the flux and reflux of the tides, is perfectly dry and whole. Some, free entirely from the damp vapour with which natural caverns in general abound. We asked the name of it. Said our guide, " The cave ol \ Kirrher Mund. sub. 112. I have translated apart of Kirclier's descriptioik father than Tournef.irt'.s, as the latter was written to support an hypothesis E 2 62 HISTORY or flated, but upon the whole amusing. " Having been informed," s;iys he, " by the natives of Paros, that in the little island of An- tipjuos, which lies about two miles from the former, of a gigantic statue that was to be seen at the mouth of a cavern in that place, it was resolved that we (the French consul and himself) fjhould pay it a visit. In pursuance of this resolution, after we had landed on the island, and walked about four mQes through the midst of beautiful plains and sloping woodlands, we at '/ength came to a little hiU, on the side of which yawned a most horrid cavern, that with its gloom at first struck us with terror, and almost repressed curiosity. Recovering the first surprise, however, we entered boldly ; and had not proceeded above twenty paces, when the supposed statue of the giant presented itself to our view. We quickly perceived, that what the ignor- ant natives had been terrified at as a giant was nothing more than a sparry concretion, formed by the water dropping from rhinit." " Wliatia Fhinn ?" said we. " Fhinn Mac CouJ, whom the trans. Intor of Ossian's work has called Fingal." How fortunate, that in this ea-^e we should meet with the remembrance of that chief, whose existence, as well as that of the whole Epic poem, is almost doubted in England. The following are the dimensions of the cave. Length of the cave from the arch without, . . . 371 feet From the pitch of the arch, 260 Breadth of the arch at the mouth, 53 At the farther end, 20 Height of the arch at the mouth, .... 117 Height of the arch at the end, 79 Height of an outside pillar, 39 Of one at the north-west corner 51 Depth of the water at the mouth, , . . ~ . . 18 At the bottom, 9 In volcanic regions there are many caves, formed by the blisters of the lava which flows during the eruption of volcanic mountains. The following is a. description of one of that kind by Sir George M'Kenzie, which he met with during his travels in Iceland, in the year 1810, in"a valley near Haviie. foird. " We proceeded to a cave (says Sir George,) about two miles to the eastward. It was nothing more than an extensive hollow, formed by one of those blisters or bubbles, hundreds of which we have walked over. Many of these are of considerable depth and great length. The bottom of this was covered with ice, and numerous icicles hung from the roof. Having lighted our lamps, we went to the end of the cave, the distance of which, from the entrance, we found to be fifty-five yards, the height not being in general more than seven or eight feet. The inside was lined with melted matter, disposed in various singular forms." THE tARTH. 53 the roof of the cave, and by degrees hardening info a figure that their fears had formed into a monster. Incited by this extraor- dinary appearance, we were induced to proceed still farther, in quest of new adventures in this subterranean abode. As we proceeded, new wonders offered themselves : the spars, formed into trees and shrubs, presented a kind of petrified grove ; some white, some green ; and all receding in due perspective, Tliey stnick us with the more amazement, as we knew them to be mere productions of nature, who, hitherto in solitude, had, in hei playful moments, dressed the scene, as if for her own amuse ment. " But we had as yet seen but a few of the wonders of the place ; and were introduced only into the portico of this amaz- ing temple. In one corner of this half-illumined recess there appeared an opening of about three feet wide, which seemed to lead to a place totally dark, and that, one of the natives assured us, contained nothing more than a reservoir of water. Upon this we tried, by throwing down some stones, which rumbling along the sides of the descent for some time, the sound seemed at last quashed in a bed of water. In order, however, to be more certain, we sent in a Leventine mariner, who, by the pro- mise of a good reward, with a flambeaux in his hand, ventured into this narrow aperture. After continuing within it for about a quarter of an hour, he returned, carrying some beautiful pieces of white spar in his hand, which art could neither imitate nor equal. Upon being informed by him that the place was full of these beautifid incrustations, I ventured in onee more with him for about fifty paces, anxiously and cautiously descending by a steep and dangerous way. Finding, however, that we came to h precipice which 1 :d into a spacious amphitheatre, if I may so call it, still deeper than any other part, we retiu-ned, and being pro- vided with a ladder, flambeaux, and other things to expedite our descent, our whole company, man by man, ventured into the same opening, and descending one after another we at last saw ourselves altogether in the most magnificent part of the cavern. " Our candles being now all lighted up, and the whole place completely illuminated, never could the eye be presented with a more glittering, or a more magnificent scene. Tlie roof all bung with solid icicles, transparent as glass, yet solid as marble. The eye could sciucely reach the loftv antrophes. Dr William Reid Cianny, of Sunderland, had, in the year 1813, turneii hia attention to the construction of a lamp which wou'd burn amongst in- flammable air, and, thou!»h an explosion might take place in the lamp, would not communicate flame to the external sunounding air. This he accomplished by means of an air-tight lamp with a glass front, the flame of whirh was supported by blowing air from a pair of small bellows through a stratum of water in the bottom of the lamp, while the heated air passed through water by a recurved tube at the top. By this process, the air within the lamp was completely insulated from the external air, and 't appears that this was the first lamp that ever was taken into a body of inflammable air in a coal-mine at the exploding point, without pro. ducing an explosion of the surrounding gas. Dr Cianny made another lamp upon an improved plan, by introducing into it the steam of water produced from a small vessel at the top of the lamp, heated by the flame. For these inventions the Doctor twice received the thanks of " The Society for prevent- ing accidents in CoaUMines;" and he also received the silver and afterwards the gold medal from the Society of Arts in London. Although these lamps, in. vented by Dr Cianny, were upon philosophical principles, displayed much Ingenuity, and were absolutely safety-lamps for mines, yet their construe, ticn prevented them from being generally used. It appears that nothing farther was attempted in this important matter, until the accident at Felling colliery, as before noticed, when Sir Humphrey Davy, Mr James Stevenson, engineer, Killingworth colliery, Newcastle, and Dr John Murray of Edin. burgh, brought forward safety-lamps, in the year 1816, each constructed up- on difterent principles. Sir Humphrey Davy's lamp was made of fine iron wire gauze, without any glass ; that of Mr Stevenson was made of a stronar glass cylinder having a metal plate at top, and another at bottom, perforated with very small holes to permit the air to pass to and from the lamp ; and that of Dr Murray was a glass lamp, or rather lanthorn, to which good at. mospheric air was brought by means of a long leather pipe from the air. course. Of these Dr Murray's lamp was not applicable but in a very few lases ; the lamps of Sir Humphrey Davy and Mr Stevenson were both com- plete safety-lamps in their primiple, and are applied in practice ; but that of Sir Humphrey Davy is decidedly the best, and is generally used in Great Britain. Having no glass it is not easily injured, and suflicient light for the miner passes through the wire gauze. To each of these gentlemen the woild is highly indebted, and in particular the mining interest of Great Britain for their individual exertions. The safety-lamp of Sir Humphrey Davy was instantly tried, and approved of by Mr Buddie, and the principal mining en. gineers at Newcastle. No one was more zealous to prove its safety and in. troduce it into the mines, than the Rev. John Hodgson, of Heworth. Kb descended the minas, entered amongst the inflammable air, aiid fully satisfied F ^ 6t HISTOUV OF Of this kind are the vapours of the mines about Bristol ; on the contrary, in other mines, a single spark struck out from the collision of flint and steel, would set the whole shaft in a flame. In such, therefore, every precaution is used to avoid a collision ; the workmen making use of wooden instruments in digging ; and being cautious, before they enter the mine, to take out even the nails from their shoes. Whence this strange difl!'erence should arise, that the vapours of some mines catch fire with a spark, and others only with a flame, is a question that we must be content to leave in obscurity, till we know more of the nature both oi mineral vapour and of fire. This we only may observe, that gunpowder will readily fire with a spark, but not with the flame of a candle ; on the other hand, spirits of wine will flame with a candle, but not with a spark : but even here the cause of this difl^erence as yet remains a secret. As from this account of mines, it appears that the internal parts of the globe are filled with vapours of various kinds, it is not surprising that they should, at different times, reach the sur- face, and there put on various appearances. In fact, much of the salubrity, and much of the unwholesomeness, of climates and soils, is to be ascribed to these vapours, which make their way from the bowels of the earth upwards, and refresh or taint the air with their exhalations. Salt mines, being naturally cold,' send forth a degree of coldness to the external air, to comfort and refresh it : on the contrary, metallic mines are known not only to warm it with their exhalations, but often to destroy all kinds of vegetation by their volatile corrosive fumes. In some mines, dense vapours are plainly perceived issuing from their mouths, and sensibly warm to the touch. In some places neither snow nor ice will continue on the ground that covers a mine ; himself of its absolute safety, in order that he might induce the miners of liis parish to use it, half of whom he liad seen so lately swept away by the dreadfu! explosion before narrated. The invention of this lamp has produced a new era in the coal mining ol ^ Grertt Britain. The steel mills were very expensive, and in certain cases produced explosions, whereas the safety-lamp can be carried without dan- ger amongst inflammable gas ready to explode : and although the wire be^ come red-hot, an explosion of the gas will take place inside of the lamp, without communicating inHammation to the external gas. I I'l.i!. Trans, vol. ii. p. 523. THE EARTH. 65 and over others the fields are found destitute of verdure.' The inhabitants, also, are rendered di'eadfully sensible of these sub- terraneous exhalations, being afl'ected with such a variety of evils proceeding entirely from this cause, that books have been pro- fessedly written upon this class of disorders. Nor are these vapours, \Thich thus escape to the surface of the earth, entirely unconfined ; for they are frequently, in a man- ner, circumscribed to a spot. The grotto Del Cane, near Naples, is an instance of this ; the noxious effects of which have made that cavern so ve.y famous. TLis grotto, which has so much employed the attention of travellers, lies within four miles of Naples, and is situated near a large lake of clear whole- some water. 5 Nothing can exceed the beauty of the landscape which this lake affords ; being surrounded with hills covered vviih forests of the most beautiful verdure, and the whole bear- ing a kind of amphitheatrical appearance. However, this region, beautiful as it appears, is almost entirely uninhabited ; the few peasants that necessity compels to reside there, looking quite consumptive and ghastly, from the poisonous exhalations that rise from the earth. The famous grotto lies on the side of a hill, near which place a peasant resides, who keeps a number of dogs for the purpose of showing the experiment to the curious. These poor animals always seem perfectly sensible of the ap- proach of a stranger, and endeavour to get out of the way. However, their attempts being perceived, they are taken and brought to the grotto ; the noxious effects of which they have so frequently experienced. Upon entering this place, which is a little cave, or hole rather, dug into the hill, about eight feet high, and twelve feet long, the observer can see no \nsib!e mark of its pestilential vapour ; only to about a foot from the bottom, the wall seems to be tinged with a colour resembling that which is given by stagnant waters. When the dog, this poor philoso- phical martyr, as some have called him, is held above this mark, he does not seem to feel the smallest inconvenience ; but when his head is thrust dovn\ lower he struggles to get free for a little ; but in the space of four or five minutes he seems to lose eI! sensation, and is taken out seemingly without life. Being plunged in the neighbouring lake, he quickly recovers, and 2 Boyle, vol. iii, p. 238. ^ Klrrhrr, Muud. Subt. voL i. p 191. CG IIISTOIIV OF is permitted to nin home, seemingly without the smallest iiijuiy. This vapour, which thus for a time suffocates, is of the hu- mid kind, as it extinguishes a torch, and sullies a looking-glass : but thi8^ of t!ie vast furnaces below." G 'i 76 HISTORY OF attempted a settlement there, have as often been obliged to de- sist. The Peak of Teneriffe is, as every body knows, a volcano, that seldom desists from eruptions. But of all parts of the earth, America is the place where those dreadful iiTegularities of nature are the most conspicuous. Vesuvius, and Etna itself, are but mere lire-works in comparison to the burning moun- ains of the Andes ; which, as they are the highest mountains of the world, so also are they the most formidable for their erup. tions. The moimtain of Arequipa, in Peru, is one of the most felebrated; Carassa and Malahallo are very considerable ; but that of Cotopaxi, in the province of Quito, exceeds any thing we have hitherto read or heard of. The mountain of Cotopaxi, as described by Uiloa,' is more than three miles perpendicular from the sea ; and it became a volcano at the time of the Spa- niards' first arrival in that country. A new eruption of it hap- pened in the year 17i3, having been some days preceded by a continual roaring in its bowels. The sound of one of these mountains is not,' like that of the volcanoes in Europe, confined to a province, but is heard at a hundred and fifty miles distance.^ " An aperture was made in the summit of this immense moun- tain ; and three more about equal heights near the middle of its declivity, which was at that time buried under prodigious masses of snow. The ignited substances ejected on that occasion, mix- ed with a prodigious quantity of ice and snow, melting amidst the flames, were carried down with such astonishing rapidity, that in an instant the valley from Callo to Latucunga was over- flowed ; and besides its ravages in bearing down the houses of the Indians, and other poor inhabitants, great numbers of people lost their lives. The river of Latucunga was the charuiel of this terrible flood ; till being too small for receiving such a pro- digious current, it overflowed the adjacent country, like a vast lake, near the towts, and ciirried away all the buildings udthin its reach. The inhabitants retired into a spot of higher ground be- hind the town, of which those parts which stood withii the limits of the current were totally destroyed. The dread of still greater devastations did not subside for three days ; during which the volcano ejected cinders, while torrents of melted ice and snow poured down its sides. The eruption lasted several days, 1 Ulloa vol. i D. 412. 2 Ibid. Tiih i.Aum. 77 and was accompanied with terrible roarings of the wind, rusiiing through the volcano, still louder than the former rumblings in its bowels. At last all was quiet, neither iire nor smoke to be seen, nor noise to be heard ; till in the ensuing year, the flames again appeared with recruited violence, forcing their passage through several other parts of the mountain, so that in clear nights the flames being reflected by the transparent ice, formed an awfully magnificent illumination." Such is the appearance and the effect of those fires which proceed from the more inward recesses of the earth : for that they generally come from deeper regions than man has hitherto explored, I cannot avoid thinking, contraiy to the opinion of Mr Buflfon, who supposes them rooted but a very little way be- low the bed of the mountain. " We can never suppose," says this great naturalist, " that these substances are ejected I'rom any great distance below, if we only consider the great force already required to fling them up to such vast heights above the mouth of the mountain ; if we consider the substances thrown up, which we shall find upon inspection to be the same with those of the moun- tain below ; if we take into our consideration, that air is always necessary to keep up the flame ; but, most of all, if we attend to one circumstance, which is, that if these substances were ex ploded from a vast depth below, the same force required to shoot them up so high, would act against the sides of the volcano, and tear the whole mountain in pieces." To all this specious rea- soning, particular answers might be easily given ; as, that the length of the funnel increases the force of the explosion ; that the sides of the funnel are actually often burst with the great violence of the flame ; that air may be supposed at depths at least as far as tLe perpendicular fissures descend. But the best answer is a well known fact ; namely, that the quantity of mat- ter discharged from .(Etna alone, is supposed, u])on a moderate computation, to exceed twenty times the original bulk of the mountain.' The greatest part of Sicily seems covered with its eruptions. The inhabitantss of Catanea have found, at\the dis- tance of several miles, streets and houses sixty feet deep, over- whelmed by the lava or matter it has discharged. But what is still more remarkable, the walls of these very houses have beea 3 Kirchcr, Muud, Subt, vol. L p. 202. HISTORY OF built of materials evidently thrown up by the mountain. The inference from all this is very obvious ; that the matter thus ex- ploded cannot belong to the mountain itself, otherwise it would have been quickly consumed ; it cannot be derived from mode- rate depths, since its amazing quantity evinces, that all the places near the bottom must have long since been exhausted ; nor can it have an extensive, and, if I may so call it, a superfacial spread, for then the country round would be quickly undermined; it must, therefore, be supplied from the deeper regions of the earth ; those undiscovered tracts where the Deity performs his wonders in solitude, satisfied with selt-approbation ! CHAP. X. or EARTHQUAKES. Having given the theory of volcanoes, we have in some mea- sure given also that of earthquakes. They both seem to proceed from the same cause, only with this difference, that the fury of the volcano is spent in the eruption ; that of an earthquake spreads wider, and acts more fatally by being confined. The volcano only affrights a province ; earthquakes have laid whole kingdoms in ruin. Philosophers ' have taken some pains to distinguish between the various kinds of earthquakes, such as the tremulous, the pu '- sative, the perpendicular, and the inclined ; but these are rather the distinctions of art than of nature, mere accidental differences arising from the situation of the country or of the cause. If, foi instance, the confined fire acts directly under a province or town, it will heave the earth perpendicularly ujjward, and pro- duce a perpendicular earthquake. If it acts at a distance, it will raise that tract obliquely, and thus the inhabitants will perceive an inclined one. Nor does it seem to me that there is much greater reason for Mr Buffon's distinction of earthquakes ; one kind of which he 1 Aristotle, Agricola, BuB'on. THE EARTH. 79 supposes* to be produced by fire in the manner of volcanoes, and confined but to a very narrow circumference. The othei kind he ascribes to the struggles of confined air, expanded bj heat in the bowels of the earth, and endeavouring to get free. For how do these two causes differ ? Fire is an agent of no power whatsoever without air. It is the air, which being at first compressed, and then dilated in a cannon, that drives the ball with such force. It is the iair struggling for vent in a vol- cano, that throws up its contents to such vast heights. In short, it is the air confined in the bowels of the earth, and acquiring elasticity by heat, that produces all those appearances which are generaliy ascribed to the operation of fire. When, therefore, we are told that there are two causes of earthquakes, we ovly learn that a greater or smaller quantity of heat produces those lerrible effects ; for air is the only active operator in either. Some philosophers, however, have been willing to give the air as great a share in producing these terrible efforts as they could ; and, magnifying its powers, have called in but a very moderate degree of heat to put it in action. Although experi- ence teU us that the earth is full of imflammable materials, and that fires are produced wherever we descend ; although it tells us that those countries where there are volcanoes, are most subject to earthquakes ; yet they step out of their way, and so find a new solution. These only allow but just heat enough to pro- duce the most dreadful phenomena, and, backing their assertions with long calculations, give theory an air of demonstration. IMr Amontons* has been particularly sparing of the internal heat in this respect ; and has shown, perhaps accurately enough, that a very moderate degree of heat may suffice to give the air amazing powers of e:-pansion. It is amusing enough, ho^rever, to trace the progress of a philosophical fancy let loose in imaginary speculations. They run thus : " A very moderate degree of heat may bring the aii into a condition capable of producing earthquakes ; for the air, at the depth of forty-three thousand five hundred and twenty- eight fathom below the surface of the earth becomes almost as heavy as quicksilver. This, however, is but a very slight depth in comparison of the distance to the centre, and is scarcely a 2 Bufibn, vol. ii. p. 32S. 3 Memoires da I'Acadamie de Scieuccs. An. 17(2. 80 HISTORY OF geveiitietli part of the way. The air, therefore, at the centre, must be infinitely heavier than mercury, or any body that we know of. This granted, we shall take something more, and say, that it is very probable there is nothing but air at the centre. Now let us suppose tiiis air heated, by some means, even to the degree of boiling water, as we have proved that the density of the air is here very great, its elasticity must be in proportion •, a heat, therefore, which at the surface of the earth would have produced but a slight expansive force, must, at the centre, pro- duce one very extraordinary, and, in short, be perfectly irresis- tible. Hence this force may, with great ease, produce earth- quakes ; and if increased, it may convulse the globe ; it may (by only adding figures enough to the calculation) destroy the Bolar system, and even the fixed stars themselves." These re- veries generally produce nothing ; for, as I have ever observed, increased calculations, while they seem to tire the memory, give the reasoning faculty perfect repose. However, as earthquakes are the most formidable ministers of nature, it is not to be wondered that a multitude of writers have been curiously employed in tlieir consideration. Wood- ward has ascribed the cause to a stoppage of the waters below the earth's surface by some accident. These being thus accu • mulated, and yet acted upon by fires, which he supposes still deeper, both contribute to heave up the earth upon their bosom. This he thinks, accounts for the lakes of water produced in an earthq\iake, as well as for the fires that sometimes burst from the earth's surface upon those dreadful occasions. There are others who have supposed that the earth may be itself the cause of its own convulsions. " When," say thoy, " the root or basis of some large tract is worn away by a fluid underneath, the earth sinking therein, its weight occasions a tremor of the adjacent parts, sometimes producing a noise, and sometimes an inu^da- tion of water." Not to tire the reader with a history of opinions instead of facts, some have ascribed them to electricity, and some to the same causes that produce thunder. It would be tedious, therefore, to give all the various opinions that have employed the speculative on this subject. The ac- tivity of the internal heat seems alone sufficient to account for every appearance that attends these tremendous irregulari- ties of natm-e. To concoivc this distinctly let us suppose THE EARTH. Si at some vast distance under the earth, large quantities of inflammable matter, pyrites, bitumens, and' marcasites, dispos- ed, and only waiting for the aspersion of water, or the hu- midity of the air, to put their fires in motion : at last, this dreadful mixture arrives -, waters find their way into those depths through the perpendicular fissures ; or air insiimates it- self through the same minute apertures : instantly new appear- ances ensue ; those substances, which for ages before lay dor- mant, now conceive new apparent qualities ; they grow hot, produce new air, and only want room for expansion. However, the narrow apertures by which the air or water bad at first ad- mission are now closed up ; yet as new air is continually gener- ated, and as the heat every moment gives this air new elasticity, it at length bursts, and dilates all round ; and, in its struggles to get free, throws all above it into similar convulsions. Thus an earthquake is produced more or less extensive, according to the depth or the greatness of the cause. * • The existence of volcanoes and hot springs led philosophers long ago to suspect that there was au inteuse heat ia the interior of the earth, 'i'he opinion of Werner, that the former arose from the combustion of masses of coal .It moderate depths, was set aside by the discovery that the seat of the volcanic agents was under the primitive rocks, of course far below the coal, formation, and that the composition of lavas was the same in all parts of the world. The notion advanced by others, that hot springs might owe their origin to the accidental mixture of substances producing chemical action in the bowels of the earth, was equally inadequate to account for the per- manency of these springs — their existence without any known change for ages. At length a tliird species of evidence presented itself in tiie tempera- ture of deep mines, which it was observed was generally higher than the mean temperature of the year in the district. It was objected that the heat might arise from the breaths of the workmen, and the lights used by them. This explanation to be sure did not account tor the difference of temperature Enid to be observed between shallow and deep mines ; but the existence of the difierence alluded to was doubted j and to this as the point upon which the controversy hinged, several philosophers, especially M. Cordier, a pro. fe&sor of geology in Paris, directed their attention. The result is thus an nouuced by the Parisian professor : — " I. Our experiments fully confirm the existence of a subterranean heat, wiiich is peculiai' to the terrestrial globe, — does not depend on the solar rays,— and increases rapidly with the depth. 2. The increase of the subterranean heat does not follow the same law over the whole earth ; it may be twice or thrice as great in one country as another. 3. These differences do not bear any constant proportion either to the lati- tude or longitude. 4. The increase is more rapid than has been supposed ; it may go as high as one degree of Fahrenheit for 2i feet, but the mean, so far ia the present observations have yet extended, cannot be fi.\ed at less than 82 HISTORY or But before we proceed with the causes, let us take a short view of the appearances which have attended the most remark, able earthquakes. By these we shall see how far the theorist corresponds with the historian. The greatest we lind in anti- one degree for 45 feet." In the deep borings made by M. Arago, it was found that the greater the depth from whiih the water ascended the wanner it was . Mr Bald of Alh)a published some facta in the Edinburgh Philosophical Jour- nal some years ago, and Mr Daubuisson gives others relating to the mines of Saxony, which establish the same conclusion. A writer in the Annals oj Philosophy thinks that the increase in England is about one degree of P'sli- renheit for every ten or twelve fathoms of descent. Hence we have reason to conclude, that it is not any peculiar local circumstances which generate the heat in warm springs ; but that they merely derive their waters from reser. voirs situated at a great depth. Pursuing this idea, the Bath wateis which have a temperature of 116, may be supposed to come from a depth of three- fourths of a mile, and at the depth of two miles downwards we should find the temperature of boiling water ; and that of melted lava at a depth wliich varies much in ditferent countries, but may be estimated on an average at GO miles. Cordier, therefore, considers the whole globe as a mass effused matter, intensely hot, covered with a solid crust or shell, whose thickness is about one 63d part of its semidiameter, and upon which crust man and all his works are suspended over the molten abyss. Hence M. Cordier considers the quan- tity of matter thrown out by volcanoes, as affording a measure of the contrac- tion which the shell of the globe is tmder going. He has examined and esti- mated the cubic contents of the matter ejected in one eruption by several volcanoes, and found that it did not amount to a cubic kilometre, that is, a cube, the side of which is rather more than half a mile. It follows, that a con- traction of volume, which would shorten the radius of the globe the 50,000th part of an inch, would be sufficient to force out the matter of one eruption. There are about 200 unextinguished volcanoes known, but many of them are silent for very long periods ; but assuming that there are on an average five eruptions in a year among them all, tliis would indicate that tlie radius of the globe shortened only one milliraetre(l-2dth part of an inch) iii a century. " This theory," says a journalist of great intelligence, "accounts for the frequency of volcanoes in the early stages of the globe's existence, when the crnst was thin, the contraction rapid, and the fracture of its parts easy. As it increases iu tliickness, changes in its figure or volume become more ditfi. cult, and must be chiefly confined to the inner coats, among which it is pro. hable that void spaces may be left ; into these the fluid matter may be injected, which in earlier times would have reached tlie surface and formed eruptions. Assuming that the thickness of the crust is 60 miles, it would require a pressure equal to that of 28,000 atmospheres to make the fused iKia reach the surface. Hence we see why such a vast number of volcanoes are found every where on the earth's surface, which were once active, but are now extinguished. In early times, when the earth was perfectly fluid at the surface, the attraction of the s:un and moon would produce tides in the molten mass exactly as it does now in the ocean. These tides, which must have been four or five yards in height, would exert a disturbing f'>rce ou the THE EAUTH. B3 fiiify is that ineiitioned by Pliny,' in uliich twelve cities in Asia Minor were swallowed up in one night ; he tells us also of another near the lake Thrasymene, which was not perceived by the armies of the Carthaginians and Romans, that were then engaged near that lake, although it shook the greatest part of Italy. In another place'^ he gives the following account of an earthquake of an extraordinary kind. " When Lucius Marcus and Sextus .Julius were consuls there appeared a very straiige pro- digy of the earth, (as I have read in the books of the Etruscan discipline,) which happened in the province of Mutina. Two mountains shocked against each other, approaching and retiring with the most dreadful noise. They at the same time, and in the midst of the day, appeared cast forth fire and smoke, while a vast number of Roman knights and travellers from the ^nii- liau Way, stood and continued amazed spectators. Several crusts, while it wa^ fonsd.idatinij, by breakirg and displai-inef its parts, and [nay have been one I'ause of th'egions of the globe where we would expect the crust to be thinnest, and the operation of the diNturbinif causes raoit violent- In all probability, it is the gaseous matter disenijageJ from the rocks during refrigeration that impregnates those mineral springs, in which a portion of such matter exists. M. Cordier ob- serves that these springs should have been more numerous in early ages, and various plienomena he thinks aimounce that tliis was the ease. The gradual re- frigoration of the earth explains other facts which have perplexed philosophers. It accounts, for instance, for so large a portion of fossil plants and animals found in cold co jntries, having the characters of those species which now belong to the tropics. Again, it has been observed, that the land surrounding the upper parts of the Baltic has risen from two to three feet within a cen- tury, while the French sciivis have inferred from certain marks at the ruins of Tanis in Egypt, that t'\f African continent is subsiding at the rate of a foot in a century. Considering all large portions of land as solid masses floating over a liquid abyss, and receiving unequal additions from beh>n', we can easily understand why one part may rise and another descend, l-aslly, as the metals are undoubtedly mixed with the fluid mass below, and the whole in consequence of its fluidity may have certain slow regular mo. tions within itself, we have a key to the mysterious phenomeua of magne. tiiiE— the variation of dip and polarity." 1 riin. lib. iL cap. SB. 2 Ibid. lib. iil, can. 35. 84 HISTORY OF towiis were destroyed by this shock ; and all the animals that were near them were killed." In the times of Trajan, the city of Antioch, and a great part of the adjacent country, was buried by an earthquake. About three hundred years after, in the times of Justinian, it was once more destroyed, together with forty thousand inhabitants ; and, after an interval of sixty years, the same ill-fated city was a third time overturned, with the loss of not less than sixty thousand souls. In the year 1182, most of the cities of Syria, and the kingdom of Jerusalem, were de- stroyed by the same accident. In the year l.SOi, the Italian his. torians describe an earthquake at Puteoli, which caused the sea to retire two hundred yards from its former bed. But one of those most particularly described in histoiy, is that of the year 1693 ; the damages of which were chiefly felt in Sicily, but its motion perceived in Germany, France, and Eng- land. It extended to a circumference of two thousand six hundred leagues ; chiefly affecting the sea-coast and great rivers; more perceivable also upon the mountains than in the valleys. Its motions were so rapid, that those who lay at their length were tossed from side to side, as upon a rolling billow.' The walls were dashed from their foundations ; and no less than fifty- fom- cities, with an incredible number of villages, were either destroyed or greatly damaged. The city of Catanea, in parti- cular, was utterly overthrown. A traveller, who was on his way thither, at the distance of some miles, perceived a black cloud, like night, hanging over the place. The sea, all of a sud- den, began to loar ; Mount .3r]tna to send forth great spires of flame ; and soon after a shock ensued, with a noise as if all the artillery in the world had been at once discharged. Our travel- ler, being obliged to alight, instantly felt himself raised a foot from the ground j and turning his eyes to the city, he, with iiinazement, saw nothing but a thick cloud of dust in the aii. The birds flew about astonished : the sun was darkened ; the beasts ran howling from the hills ; and although the shock did not continue above three minutes, yet near nineteen thousand of the inhabitants of Sicily perished in the ruins. — Catanea, to which city the describer was travelling, seemed the principal Bcene of ruin ; its place only was to be found ; and not a footstep of its former magniriccnce was to be seen remaining. THE EARTH. 85 The earthquake which happened in Jamaica, in 1G92, was very terrible, and its description sufficiently minute. " In two miimtes' time it destroyed the town of Port Royal, and sunk the houses in a gulf forty fathoms deep. It was attended with a hollow rumbling noise, like that of thunder; and, in less than a minute, three parts of the houses, and their inhabitants, were all sunk quite under water. While they were thus swallowed up on the one side of the street, on the other the houses were thrown into heaps ; the sand of the streets rising like the waves of the sea, lifting up those that stood upon it, and immediately over- whelming them in pits. All the wells discharged their waters with the most vehement agitation. The sea felt an equal share of turbulence, and, bursting over its mounds, deluged all that tame in the way. The fissures of the earth were, in some places, so grept, that one of the streets appeared twice as broad as for- merly. In many places, however, it opened and closed again, and continued this agitation for some time. Of these openings, two or three hundred might be seen at a time ; in some whereof the people were swallowed up ; in others, the earth closing, caught them by the middle, and thus crushed them instantly to death. Other openings, stiU more dreadful than the rest, swal- lowed up whole streets ; and others, more formidable, spouted up whole cataracts of water, drowning such as the earthquake had spared. The whole was attended with the most noisome stench ; while the thundering of the distant falling mountains, the whole sky overcast with a dusky gloom, and the crash of falling habitations, gave unspeakable horror to the scene. After this dreadful calamity was over, the whole island seemed con- verted into a scene of desolation ; scarcely a planter's house was left standing ; almost all were swallowed up ; houses, people, trees, shared one universal ruin : and in their places appeared great pools of water, which when dried up by the sun, left only a plain of barren sand, without any vestige of former inhabitants, filost of the rivers, during the earthquake, were stopped up by the falluig in of the mountains ; and it was not till after some time they made themselves new channels. The mountains seemed paiticularly attacked by the force of the shock ; and it was sup- posed that the principal seat of the concussion was among them. Those who were saved got on board ships in the harbour, where H m-JTO:'. V II!" I, ■■.:■.■■, iiiiiiiined iibu-. L- i\\u uijiii:jr- ; ii^e Miucks continuing, dur. iiig that interval, with more or less violence every day." As this description seems to exhibit all the appearances thai usually make up the catalogue of terrors belonging to an earth- quake, I v.'ill suppress the detail of that which happened at Lis- bon in our own times, and which is too recent to require a de- scription.* In fact there are few particulars in the accounts of « Goldsmith here alludfis to the great earthquake of 1755. It appears to have originated beneath the Atlantic Ocean, the waves of which received almost as viiilent a concussion as the land. Its effects were even extended to the waters in many placi-s where the shocks were not perceptible. It ppfvaded Hie greater portions of the continents of Europe, Africa, and America; but its extreme violence was exercised on the south-western parts of the for- mer. Lisbon, the Portuguese capital, had already suffered greatly from an earthquake in 1631 ; and, since the calamity about to be described, has liad three such visitations, in 1761, 1765, and 1772, which were not however at- tended by equally disastrous consequences. In the present instance, it had been remarked, that, since the commencement of the year 1750, less rain had fallen than had been known in the memory of the oldest of their inhabitants, unless during the spring preceding the calamitous event. The summer had been un. a?ually cool, and the weather fine and clearfor the last forty days. Atlengtli, on the 1st of November, about forty minutes past nine in tlie morning, a most violent shock of an earthquake was felt; its duration did nut exceed six seconds ; but so powerful was the concussion, that it overthrew every church and convent in the city, together with the royal palace and the magoificeiit opera-house adjoined to it ; in short, not any building of consequence escap- ed. About one fourth of the dwelling-houses were thrown down : and, at a moderate computation, 30,000 individuals perished. Between the 1st and Sth of November, twenty-two shocks «-ere reckont'd. This earthquake was also felt at Opor*», Cadiz, and other parts of Europe, and equally severe in Africa. A great, part of the city of Algiers was destroyed. In many places of Germany the effects of this earthquake weie very perceptible; but in Holland the agitations were still more remarkable. The agitation of the waters was also perceived in various parts of Great Britain and Ireland. At sea, the shocks of this earthquake were felt most violently. Among otl.«r catastrophes, the captain of the Nancjj frigate, off St Lucar, felt his ship so violently shaken, that he thought she had struck the groimd, but on heaving the lead, found she was in a great depth of water. The earthquakes in Sicily and the two Calabrias began on the Sth of February 1783, and continued until the latter end of the Blay following ; doing infinite damage, and exhibiting at Mesaina, in the parts of Sicily nearest to the continent, and in the two Calabrias, a varietvof phenomena. The earth was in a constant tremor, and its motions were various, being either vertical or whirling round, — horizon, tal or oscillatory, that is, by pulsations or beatings from the bottom upwards. There were many openings, or cracks in the earth ; and several hUis had been lowered, while others were quite level. lu the plains, the chasms were bo deep that many roads were readcred impassable. Huge mountains w«ra THE EARTH. 87 tbose who were pvesent at that scene of de=?olation. that, we have not more minutely and accurately transmitted to us by form'T wi-iters, whose narratives I have for that reason preferred. I will therefore close this description of human calamities with the account of the dreadful earthquake at Calahria, in 16.38. It is related by the celebrated Father Kircher, as it happened while he was on his journey to visit Mount ^tna, and the rest of the wonders that lie towards the south of Ifcily. I need scarcely inform the reader, that Kircher is considered, by scholars, as one of the greatest prodigies of learning. " Having hired a boat, in company with four more, two friars of the order of St Francis, and two seculars, we launched, on the twenty-fourth of March, from the harbour of Messina in Sicily, and arrived the same day at the promontory of Pelorus. Our d-rstination was for the city of Euphoemia, in Calabria, severed, and portions of tliera driven into the valleys, which were thus filled up. The total amount of the mortality occasioned by these earthquakes in Sicily and the two Calabrias, was, agreeably to the official returns, .'52,367 ; but Sir William Hamilton thought it stUl greater, and carries his estimation to 40,000, including- foreigners. The shocks felt since the commencement of these formidable earthquake^ amounted to several hundreds ; and among the most violent may be reckoned the one which happened on the 29th of March. It aifected most of the higher parts of Upper Calabria, and the inferior part of Lower Calabria, being equally treraendi>us with the first. Indeed these shocks were the only ones sensibly felt in the capital, Naples. With relation to the former, two singrilar phenomena are recorded. At a distance of about three miles from the ruined city of Oppido, in Upper Calabria, was a hill, having a sandy and clayey soil, nearly -100 feet in height, and nearly 900 feet in circumference at its base. This hill is said to have been carried to the dis- tance of about four miles from the spot where it stood, into a plain called Campo de Bassano. At the same time, the hill on which the city of Oppido stood, and which extended about three miles, divided into two parts, being situated between two rivers, its ruins filled up the valley, and stopped their course, forming two large lakes, which augmented daily. By the earthquake experienced in Chili in 1822, a great line of coast is stated to have been lifted permanently up to the height of several feet above its former level : and il deserves remark, that though earthquakes are sometimes felt in the interioi of countries, their most terrible eflfects occur chiefly along the coast. On the 2d March, 1825, the city of Algiers was visited with a tremendous earth- quake, which destroyed at least 10,000 human beings. It is worthy of remark, that the same phenomena which generally precedes the eruption of .^tna and Vesuvius, occured at Bluda, on this occasion ; namely, all the wells and foun. tains in the neighbourhood becaine perfectly dry. The bar">met:'r had fallen gradually for someday? b?fore the earthquake; and the thermometer rose suddenly from 5S to Ci^ degrees on iIin rl:i.y it Iiappened. h2 88 HISTORY OF (vhere we had some business to transact, and where we designed to tarry for some time. However, Providence seemed willing to cross our design ; for we were obliged to continue for three days at Pelorus, upon account of the weather ; and though we often put out to sea, yet we were as often driven back. At length, however, wearied with the delay, we resolved to prosecute our voyage ; and, although the sea seemed more than usually agitat. ed, yet we ventured forward. The gulf of Charybdis, which we approached, seemed whirled round in such a manner, as to form a vast hollow, verging to a point in the centre. Proceeding on- wai'd, and turning my eyes to .^tna, I saw it cast forth large volumes of smoke, of mountainous sizes, which entu'ely covered the whole island, and blotted out the very shores from my view. This, together with the dreadfid noise, and the sulphureous stench, which was strongly perceived, filled me with apprehen- sions that some more dreadful calamity was impending. The sea itself seemed to wear a very unusual appearance ; those who have seen a lake in a violent shower of rain covered all over with bubbles, will conceive some idea of its agitations. My surprise was still increased by the calmness and serenity of the weather ; not a breeze, not a cloud, which might be supposed in put all nature thus into motion. I therefore warned my com- panions that an earthquake was approaching ; and, after some time making for the shore with all possible diligence, we landed at Tropte, happy and thankful for having escaped the threaten- ing dangers of the sea. " But our triumphs at land were of short duration : for we had scai'cely arrived at the Jesuits' College in that city when our ears were stunned with a horrid sound, resembling that of an infinite number of chariots driven fiercely forward, the wheels rattling, and the thongs cracking. Soon after this, a most dread- ful earthquake ensued, so that the whole tract upon which we stood, seemed to vibrate, as if we wei-e in a scale of a balance that continued wavering. This motion, however, soon grew more violent ; and being no longer able to keep my legs, I was thrown prosti'ate upon the ground. In the mean time, the imi versal ruin round me redoubled my amazement. The crash of falling houses, the tottering of towers, and the groans of the dying, all contributed to raise my terror and despair. On ev erv §ide of me I saw nothing but a scene of ruin, and danger thr eat- THE EARTH. 89 ening wherever I should fly. I comrDended myself to God, as mv last great refuge. At that hour, O how vain was every sublu- nary happiness ! wealth, honour, empire, wisdom, all mere use 1 ess sounds, and as empty as the bubbles in the deep. Just stand- ing on the threshold of eternity, nothing but God was my plea- sure ; and the nearer I approached, I only loved him the more. — After some time, however, finding that I remained unhurt amidst the general concussion, I resolved to ventiu-e for safety, find running as fast as I could, reached the shore, but almost terrified out of my reason. I did not search long here till I founrf the boat in which I had landed, and my companions also, whose terrors were even greater than mine. Our meeting was not of that kind v/here every one is desirous of telling his own happy escape ; it was all silence, and a gloomy dread of impending terrors. " Leaving this seat of desolation, we prosecuted our voyage along the coast, and the next day came to Rochetta, where we landed, although the earth still continued in violent agitations. But we were scarcely arrived at our inn, when we were once more obliged to return to the boat, and in about half an hour we saw the greatest part of the town, and the inn at which we had set up, dashed to the ground, and burying all its inhabitants beneath its ruins. " In this manner, proceeding onward in our little vessel, find- ing no safety at land, and yet, from the smallness of our boat having but a very dangerous continuance at sea, we at length landed at Lopizium, a castle midway between Tropae and Eu- phoemia, the city to which, as I said before, we were bound. Here, wherever I turned my eyes, nothing but scenes of rain and horror appeared ; towns and castles levelled to the ground • Strombolo, though at sixty miles distance, belching forth flames in an unusual manner, and with a noise which I could distinctly hear But my attention was quickly turned from more remote to con- tiguous danger. The rumbling sound of an approaching earth- quake, which we by this time were grown acquainted with, alarmed us for the consequences ; it every moment seemed to grow louder, and to approach more near. The place on which we stood now began to shake most dreadfully, so that bein^ unable to stand, my companions and I caught hold of whatevei shrub grew next us, and supported ourselves in that manner. H 3 90 HisroaY of "After some lime, tliis violent paroxysm ceasing, we again stood up, in order to prosecute our voyage to Eupliteniia, that lay within sight. In the mean time, while we were preparing for this purpose, I turned my eyes towards the city, but could see only a frightful dark cloud that seemed to rest upon the place. This the more surprised us, as the weather was so very serene. We waited, therefore, till the cloud was passed away : then turning to look for the city, it was totally sunk. Wonder- ful to tell ! nothing but a dismal and putrid lake was to be see " where it stood. We looked about to find some that could tell us of its sad catastrophe, but could see none ! All was become a melancholy solitude ! a scene of hideous desolation ! Thus proceeding pensively along, in quest of some human being that could give us some little information, we at length saw a boy sitting by the shore, and appearing stupified with terror. Of him, therefore, we inquired concerning the fate of the city, but he could not be induced to give us an answer. We intreated him with every expression of tenderness and pity to tell us : but his senses were quite wrapt up in the contemplation of the dan- ger he had escaped. We offered him some victuals, but he seemed to loathe the sight. We still persisted in our oflices of kindness ; but he only pointed to the place of the city, like one out of his senses ; and then running up into the woods, was never heard of after. Such was the fate of the city of Euphaemia! and as we continued our melancholy course along the shore, the whole coast, for the space of two hundred miles, presented no- thing but remains of cities, and men scattered, without a habita- tion, over the fields. Proceeding thus along, we at length ended our distressful voyage by arriving at Naples, after having escaped a thousand dangers both at sea and land. " The reader, I hope, will excuse me for this long translation from a favourite writer, and that the sooner, as it contains some particidars relative to earthquakes not to be found elsewhere. From the whole of these accounts we may gather, that the most concomitant circumstances are these : A rumbling sound before the earthquake. This proceeds from the air or fire, or both, forcing their way through the chasms of the earth, and endeavouring to get free ; which is also heard in volcanoes. A violent agitation or heaving of the sea, sometimes before THE EARTH. 91 and sometimes after that at land. This agitation is only a simi- lar effect produced on the waters with that at land, and mav be called, for the sake of perspicuity, a seaquake ; and Xtii also is produced by volcanoes. A spouting up of waters to great heights. It is not easy to describe the manner in which this is performed : but volcanoes also perform the same; Vesuvius being known frequently to eject a vast body of water. A rocking of the earth to and fro, and sometimes a perpen- dicular bouncing, if it may be so called, of the same. This dif ference chiefly arises from the situation of the place with respect to the subterranean fire. Directly under, it lifts ; at a farther distance, it rocks. Some earthquakes seem to travel onward, and are felt in dif- ferent countries at diiferent hours the same day. This arises from the great shock being given to the earth at one place, and that being communicated onward by an undulatory motion, suc- cessively affects different regions in its progress ; as the blow- given by a stone falling in a lake, is not perceived at the shores till some time after the first concussion. The shock is sometimes instantaneous, like the explosion of gunpowder ; and sometimes tremulous, and continuing for sev- eral minutes. The nearer the place where the shock is first given, the more instantaneous and simple it appears. At a greater distance, the eaith redoubles the first blow with a sort of vibratory continuation. As waters have generally so great a share in producing earth- quakes, it is not to be wondered that they should generally fol- low those breaches made by the force of fire, and appear in the great chasms which the earthquake has opened. These are some of the most remarkable phenomena of earth- quakes, presenting a frightful assemblage of the most terrible effects of air, earth, fire, and water. The valley of Solfatara, near Naples, seems to exhibit, in a minuter degree, whatever is seen of this horrible kind on the great theatre of nature. This plain, which is about twelve hun- dred feet long, and a thousand broad, is embosomed in moim- tains, and has in the middle of it a lake of noisome blackish water, covered with a bitumen, that floats upon its surface. In svery part of this plain, caverns appear smoking with sulnhur, 92 HISTORY OF and often emitting flames. Tiie earth, wherever we walk over it, trembles beneath the feet. Noises of flames, and the hissinf* of waters, are heard at the bottom. The water sometimes spouts up eight or ten feet high. The most noisome fumes, foetid water, and sulphureous vapours, offend the smell. A stone thrown into any of the caverns, is ejected again with consider- able violence. These appearances generally prevail, when the sea is any way disturbed : and the whole seems to exhibit the appearance of an earthquake in miniature. However, in this smaller scene of wonders, as well as in the greater, there are many appearances for which, perhaps, we shall never account ; and many questions may be asked, which no conjectures can thoroughly resolve. It was the fault of the philosophers of the last age, to be more inquisitive after the causes of things than after the things themselves. They seemed to think that a con- fession of ignorance cancelled their claims to wisdom ; they, therefore, had a solution for every demand. But the present age has grown, if not more inquisitive, at least more modest ; and none are now ashamed of that ignorance, which labour can neither remedy nor remove. CHAP. XI. OF THE APPEARANCE. OF NEW ISLANDS AND TRACTS ; AND OF THE DISAPPEARING OF OTHERS. Hitherto we have taken a sur\'ey only of the evils which ai'e produced by subterranean fires, but we have mentioned nothing of the benefits they may possibly produce. They may be of use in warming and cherishing the ground, in promoting vegeta- tion, and giving a more exquisite flavour to the productions of the earth. The imagination of a person who has never been out of our own mild region, can scarcely reach to that luxuriant beauty with which all nature appears clothed in those very coun- tries that we have but just now described as desolated by earth- quakes, and undermined by subterranean fires. It must he gi'anted, therefore, that though in those regions they have a greater share in the dangers, thev have also a larger proportior in the benefits of nature. THE EAHTH. 93 Kut there is another advantage arising from subterranean fires, which, though hitherto disregarded by man, yet may one day become serviceable to him ; I mean, that while they are found to swallow up cities and plains in one place, they are also known to produce promontories and islands in another. We have many instances of islands being thus formed in the midst of the sea, which though for a long time barren, have afterwaids become fruitful seats of happiness and industry. New islands are formed in two ways ; either suddenly, by the action of subterraneous fires ; or more slowly, by the deposition of mud, carried down by rivers, and stopped by some accident.' With respect particularly to the first, ancient historians, and modern travellers, give us such accounts as we can have no room to doubt of. Seneca assures us, that in his time the island of Therasia appeared unexpectedly to some mariners, as they were employed in another pursuit. Pliny assures us, that thir- teen islands in the INIediterranean appeared at once emerging from the water ; the cause of which he ascribes rather to the retiring of the sea in those parts, than to any subterraneous elevation. However, he mentions the island of Hiera, near that of Therasia, as formed by subterraneous explosions ; and adds to his list several others formed in the same manner. In one of which he relates that fish in great abundance were found, and that all those who ate of them died shortly after. " On the twenty-fourth of May,' in the year 1707, a slight earthquake was perceived at Santorin ; and the day following, at sun-rising, au object was seen by the inhabitants of that island, at two or three mUes distance at sea, which appeared like a floating rock. Some persons, desirous either of gain, or incited by curiosity, went there, and found, even while they stood upon this rock, that it seemed to rise beneath their feet. They per ceived also, that its surface was covered with pumice-stones ai:d oys^ters, wLicu it had raised from the bottom. Every day after, until the fourteenth of June, this rock seemed considerably to increase ; and then was found to be half a mile round, and about thirty feet above the sea. The earth of which it was composed seemed whitish, with a small proportion of clay. Soon after this the sea again appeared troubled, and streams arose which I Buffon, vol, ii. p. 343. 2 Hist, de 1' Acid. an. n(R p. 23. O-l HiSTon\ or jveie very ofi'ensive to the inhabitants of Santorin. But on the sixteenth of the succeeding month, seventeen or eighteen rocks more were seen to rise out of the sea, and at length to join to- gether. All this was accompanied with the most terrible noise, and fires which proceeded from the island that was newly formed. The whole mass, however, of all this new formed earth, uniting, ncreased eveiy day, both in height and breadth, and, by the torce of its explosions, Cast forth rocks to seven miles distance. This continued to bear the same dreadful appearances till the month of November in the same year; and it is at present a volcano, which sometimes renews its explosions. It is about three miles in circumference ; and more than from thirty-five to forty feet high." It seems extraordinary, that, about this place in particular, islands have appeared at different times, particularly that of Hiera, mentioned above, which has received considerable addi- tions in succeeding ages. Justin tells us,' that at the time the JMacedonians were at war with the Romans, a new island appeared between those of Theramenes and Therasia, by means of an earthquake. We are told that this became half as large again about a thousand years after, another island rising up by its side, and joining to it, so as scarcely at present to be distin- guished from the former. A new island was formed, in the year 1720. near that of Ter- cera, near the continent of Africa, by the same causes. In tlie beginning of December, at night, there was a terrible earthquake at that place, and the top of a new island appeared, which cast forth smoke in vast quantities. The pilot of a ship, who ap- proached it, sounded on one side of this island, and could not find ground at sixty fathom : at the other side, the sea was totally tinged of a different colour, exhibiting a mixture of white, blue, and green ; and was very shallow. This island, on its first appearance, was larger than it is at present ; for it has since that time sunk in such a manner, as to be scarcely above water.'' 1 Justin, lib. xxx. cap. 4. 2 In tlie spriiif; of 178ri, a voloanie island was formed about .30 inilos from the soutli-west point, oi Iceland. The discovtrer, Captiiin Von Lowe iiiiorn, in the Danish service, « ho arrived just at tlie tin;e of the tiist eruption, when .^moke and tiaines ascended out of the sea, relates that no i.sland or any laiid could be seen, from which Ihese tiaines couM originate. No wonder, THE EAETH. 95 A traveller, whom these appearances could not avoid affect- ing, speaks of them in this manner .^ " What can be more sur. jirising than to see fire not only break out of the bowels of the earth, but also to make itself a passage through the waters of the sea ! ^Vhat can be more extraordinary, or foreign to our common notions of things, than to see the bottom of the sea rise up into a mountain above the water, and to become so firm an island as to be able to resist the violence of the greatest storms. I know that sub- terraneous fires, when pent in a narrow passage are able to raise up a mass of earth as large as an island : but that this should be done in so regular and exact a manner, that the water of the tea should not be able to penetrate and extinguish those fires ; that after hasang made so many passages, they should retain force enough to raise the earth ; and, in fine, after ha\ing been extinguished, that the mass of earth should not fa.l down, or sink again with its own weight, but still remain in a manner suspended over the great arch below ! This is what to me seems more surprising than any thing that has been related of Mount ^tna, Vesuvius, or any other volcano." Such are his sentiments : however, there are few of these appearances any way more extraordinary than those attending volcanoes and earthquakes in general. We are not more to be surprised that inflammable substances should be found beneath the bottom of the sea, than at similar depths at land. These have all the force of fire giving expansion to air, and tending to raise the earth at the bottom of the sea, till it at length heaves above water. These marine volcanoes are not so frequent ; for, if we may judge of the usual procedure of nature, it must very often happen, that before the bottom of the sea is elevated above the surface, -i. chasm is opened in it, and then the water I ressing in, extinguishes the volcano before it has time to pro- then, that he fell into the greatest consternation, when, as he expresses hlra. self, he saw the waves on tire. The following year, the Danish governraen directed, that all ships bound to Iceland should examine the new-formed island ; but so entirely had it Tanished, that none of them either saw or could discover the smallest trace of it. However, towards the end of the next year, n Danish ship of war, of 64 guns, was wrecked on this rock ; which is nov» no longer visible, but remains a most dangerous rock nearly level with the surface of the water. 3 PhU. Trans, vol v. p. 197. 96 History of duce its effects. This extinction, however, is not efl'ected with- out very great resistance from the fire beneath. The water, upon dashing into the cavern, is very probably at first ejected back with great violence ; and thus some of those ajnazing water-spouts are seen, which have so often astonished the mari- ner, and excited curiosity. But of these in their place. Besides the production of those islands by the action of fire, there are others, as was said, produced by rivers or seas carry- ing mud, earth, and such like substances, along with their cur- rents; and at last depositing them in some paiticular place.* At the mouths of most great rivers, there are to be seen banks, thus formed by the sand and mud carried down by the stream, which have rested at that place, where the force of the current is diminished by its junction with the sea. These banks, by slow degrees, increase at the bottom of the deep : the water in those places is at first found by mariners to grow more shallow ; the bank soon heaves up above the surface ; it is considered, for a while, as a tract of useless and barren sand ; but the seeds of some of the more hardy vegetables are driven thither by the * Islands of coral are also formed in tropical regions. Coral is the produce of different species of vermes or worms, and it consists cliiefly of carbonate of lime. Now it is difficult to conceive where these animals procure such prodigious quantities of this substance. Sea- water indeed contains traces of sulphate of lime, but no other calcareous salt, as far as is known. Hence it would appear, that these creatures must either decompose sulphate of lime, though the qnan. tity of that salt contained in sea- water seems inadequate to supply their wants, or they must form carbonate of lime from the constituents of sea-water in a way totally above our conception. Be that as it may, there is one con- sequence of this copious formation of coral in the tropical regions of con.sider. able importance to navigation. The winds and waves accumulate these corals iu large banks, which, entangling the sand, gradually rise above the surface of the vv'aves, and form islands. These, in process of time, probably by the agency of birds, become covered with vegetation, and frequently load- ed with timber. Mr Ellis, in his history of zoophytes, supposes that the greater part of these numerous islands in the South Sea, have been formed by coral, rising above the surface of the water. The bottom of these islands la nothing else than a coral bank; the surface is a black soil, formed of B mixture of sand and decayed vegetable matter; the whole island is flat, long, and narrow ; and extends usually in its greatest length from north to south, because almost all winds between the tropics blow either from the east or the west. The sides of tliese islands frequently constitute ■} perpendicular wall ; and the sea. at a little distance from them, is of an uufa homable depth. THE EARTH. 97 wind, take root, and thus binding the sandy surface, the whole spot is clothed in time with a beautiful verdure. In this manner there are delightful and inhabited islands at the mouths of many rivers, particularly the Nile, the Po, the Mississippi, the Ganges, and the Senegal. There has been, m the memory of man, a beautiful and large island formed in this manner at the mouth of the river Nanquin, in China, made from depositions of mud at its opening : it is not le^s than sixty miles long, and about twenty broad. La Lou- bere informs us,' in his voyage to Siam, that these sand-banks increase every day, at the mouths of all the great rivers in Asia; and hence, he asserts, that the na\agation up these rivers be- comes every day more diiBcult, and will, at one time or other, be totally obstructed. The same may be remarked with regard to the Wolga, which has at present seventy openings into the Caspian sea ; and of the Danube, which has seven into the Euxine. We have had an instance of the formation of a new island not very long since at the mouth of the Humber, in Eng- land. " It is yet within the memory of man," says the relator,* " since it began to raise its head above the ocean. It began its appearance at low water, for the space of a few hours, and was buried again tiU the next tide's retreat. Thus successively it lived and died, until the year iC66, when it began to maintain its ground against tlie insult of the waves, and then first invited the aid of human industry. A bank was thrown about its ris- ing grounds, and being thus defended from the incursions of the sea, it became firm and solid, and, in a short time, afforded good pasturage for cattle. It is about nine miles in circumference, and is worth to the proprietor about eight hundred pounds a year." It would b^ endless to mention aU the islands that have been thus formed, and the advantages that have been derived from them. How ever, it is frequently found, that new islands may often be considered as only turning the rivers from their former bed ; so that in proportion as land is gained at one part, it is lost by the overflowing of some other. Little, therefore, is gained by such accession ; nor is there much more by the new islands which are sometimes formed from 1 Lvttres Cnneuses et Edifiantes, sec. xi. p. 231. 2 Pliil. Trans, vol.iv. p. 251. I 98 HISTORY OF the spoils of the continent. Mariners assure us, that there are sometimes whole plains unrooted from the main lands, by Hoods and tempests. These being carried out to sea, with all their trees and animals upon them, are frequently seen floating in the ocean, and exhibiting a surprising appearance of rural tranquil- lity in the midst of danger. The greatest part, however, hav- ing the earth at their I'oots at length washed away, are dispersed and their animals drowned ; but now and then some are found to brave the fury of the ocean, till being stuck either among rocks or sands, they again take firm footing, and become per- manent islands. As different causes have thus concurred to produce new islands, so we have accounts of others, that the same causes have contributed to destroy. We have already seen the power of earthquakes exerted in sinking whole cities, and leaving lakes in their room. There have been islands, and regions also, that have shared the same fate ; and have sunk with their inhabi- tants never more to be heard of. Thus Pausanias ' tells us of an island called Chryses, that was sunk near Lemnos. Pliny mentions several ; among others, the island of Cea, for thirty miles, having been washed away, with several thousands of its inhabitants. But of all the noted devastations of this kind, the total submersion of the island of Atalantis, as mentioned by Plato, has been most the subject of speculation. Mankind, in general, now consider the whole of his description as an ingenious fable ; but when fables are grown famous by time and authority, they become an agreeable, if not a necessary, part of literary in- I'ormation. " About nine thousand years are passed," says Plato," " since the island of Atalantis was in being. The priests of Egypt were well acquainted with it ; and the first heroes of Athens gained much glory in their wars with the inhabitants. This island was as large as Asia Minor and Syria united ; and was situated beyond the Pillars of Hercules, in the Atlantic ocean. The beauty of the buildings, and the fertility of the soil, were far beyond any thing a modern imagination can conceive : gold 1 Pausanias, I. 8. in Arcad. p. 505. 2 Plato in Critiu. THE EARTH. 99 and ivory were every where common ; and the fruits of the earth offered themselves without cultivation. The arts and the courage of the inhabitants were not inferior to the happiness of their situation ; and they were frequently known to make con- quests, and overrun the continents of Europe and Asia." The imagination of the poetical philosopher riots in the description of the natural and acquired advantages, which they long enjoyed in this charming region. " If," says he, " we compare that country to our own, ours will appear a mere wasted skeleton, when opposed to it. Their mountains, to the very tops, were clothed with fertility, and poured down rivers to enrich the plains below. " However, all these beauties and benefits were destroyed in one day by an earthquake sinking the earth, and the sea overwiielming it. At present not the smallest vestiges of such an island are to be found ; Plato remains as the only authority for its existence ; and philosophers dispute about its frituatioiu It is not tor me to enter into the controversy, when there appears but little probability to support the fact ; and, in- deed, it would be useless to run back nine thousand years in search of difficulties, as we are surrounded with objects that more closely affect us, and that demand admiration at our very doors. When I consider, as Lactantius suggests, the various vicissitudes of nature ; lands swallowed by yawning earthquakes, or over- whelmed in the deep ; rivers and lakes disappearing, or dried away ; mountains levelled into plains ; and plains swelling op into mountains ; I cannot help regarding this earth as a place of very little stability ; as a transient abode of still more transitory beings. CHAP. XII. OF MOUNTAINS. Having at last, in some measure, emerged from the deeps of the earth, we come to a scene of greater splendour ; the conteni- plation of its external appearance. In this survey, its mom-. i2 1(X) HISTOHY OF tains arc the first objects that strike the imagination, and excite our curiosity. There is not, perhaps, any thing in ail nature that impresses an unaccustomed spectator with sucli ideas of awful solemnity, as these immense piles of Nature's erecting, that seem to mock the minuteness of human magnificence. In countries where there are nothing but plains, the smallest elevations are apt to excite wonder. In Holland, which is all a flat, they show a little ridge of hills, near the sea-side, whicli Boerhaave generally marked out to his pupils, as being moun- tains of no small consideration. What would be the sensations of such an auditory, could they at once be presented with a view of the heights and precipices of the Alps or the Andes ! Even among us in England, we have no adequate ideas of a mountain- prospect ; our hills are generally sloping from the plain, and clothed to the very top witn verdure : we can scarcely, there- fore, lift our imaginations to those immense piles, whose tops peep up behind intervening clouds, sharp and precipitate, and reach to heights that human avarice or curiosity have never been able to ascend. We, in this part of the world, are not, for that reason, so immediately interested in the question which has so long been agitated among philosophers, concerning what gave rise to these inequalities on the surface of the globe. In our own happy region, we generally see no inequalities but such as contribute to use and beauty ; and we therefore are amazed at a question, inquiring how such necessary inequalities came to be formed, and seeming to express a wonder how the globe comes to be so beautiful as we find it. But though with us there may be no great cause for such a demand, yet in those places where moun- tains deform the face of nature, where they pour down cataracts, or give fury to tempests, there seems to be good reason for in- quiry either into their causes or their uses. It has been, thert- fore, asked by many, in what manner mountains have come to be formed ; or for what uses they are designed ? To satisfy curiosity in these respects, much reasoning Las been employed, and very little knowledge propagated. Witli regard to the first part of the demand, the manner in which mountains were formed, we have already seen the conjectures of different philosophers on that head. One supposing that they were formed from the earth's broken shell at the time of the THE EARTH. 10 I d eluge ; another, that they existed from the creation, and onlj acquired their deformities in process of time ; a third, that thej owed their original to earthqiuakes ; and still a fourth, with niu'jh more plausibility than the rest, ascribing them entirely to the fluctuations of the deep, which he supposes in the beginning to have covered the whole earth. Such as are pleased with dis- quisitions of this kind, may consult Burnet, Whiston, Woodward, or ISuffon. Nor would I be thought to decry any mental amuse- ments, that at worst keep us innocently employed ; but, for my own part, 1 cannot help wondering how the opposite demand has never come to be made ; and why philosophers have never asked how we come to have plains ? Plains are sometimes more prejudicial to man than mountains. Upon plains, an in- undation has greater power ; the beams of the sun are often col- lected Lhere with suffocating fierceness; they are sometimes found desert for several hundred miles together, as in the coun- try east of the Caspian sea, although otherwise fruitful, merely because there are no risings or depressions to form reservoirs, or collect the smallest rivulet of water. The most rational answer, therefore, why either mountains or plains were formed, aeems to be that they were thus fashioned by the hand of Wis. dom, in order that pain and pleasure should be so contiguous, a* that morality might be exercised either in bearing the one, or oommunicating the other. Indeed, the more I consider this dispute respecting the for. mation of mountains, the more I am struck with the futility of ihe question. There is neither a straight line, nor an exact superficies, in all nature. If we consider a circle, even with mathematical precision, we shall find it formed of a number of small right lines, joining at angles, together. These angles, therefore, luay be considered in a circle as mountains are u^«on our globe ; and to demand the reason for the one being moun- tainous, or the other angular, is only to ask, why a circle is a circle, or a globe is a globe. In short, if there be no surface without inequality in nature, why should we be surprised that the earth has such ? It has often been said, that the inequal- ities of its surface are scarce distinguishable, if compared to its magnitude ; and I think we have every reason to be content with the answer. S'jnic, however, have avoided the difficulty hv urging the final IS 102 HISTORt" OF eause. Tliey allege, that mountains have been formed merely because they are useful to man. This carries the inquirer but a part of the way ; for no one can aifirm, that in all places they are useful. The contrary is known by horrid experience, in taose valleys that are subject to their influence. However, as the utility of our earthly habitation is a very pleasing and flat- tering speculation to every philosopher, it is not to be wondered that much has been said to prove the usefulness of these. For this purpose many conjectures have been made, that have re- reived a degree of assent even beyond their evidence ; for mei! were unwilling to become more miserably wise. It has been alleged, as one principal ad^•antage that we de- rive from them, that they serve like hoops or ribs, to strengthen our earth, and to bind it together. In consequence of this the- ory, Kircher has given us a map of the earth, in this manner hooped with its mountains ; which might have a much more solid foundation, did it entirely correspond with truth.* •According to Werrrr, the rocks of which this globe is composed, as far aa they have been penetrated below the surface, ainouut to 3G, and they all (jc- cupy a determinate position with respect to each other. They extend round the whole earth, and inclose the central nucleus like the coats of an onion. Not that they are every where spherical, or uninterrupted: partly on ing to inequalities in the centre nucleus, over which they are deposited, and partly to oHier causes, they rise higher in one place, and sink lower in an- other, sometimes slowly, and sometimes abruptly; and they are entirely wanting in many particular spots, having either never been deposited, or hav- ing been removed and carried away by some unknown cause. The position oi the ditferent rocks being thus constant, has been pitched upon as the basiS cf the classification of them. They have been divided into live classes; and the t?Tm formation has been applied to them, from the supposition that each class has been formed about the same time. Those rocks which lie lowest iown, or nearest the central nucleus, belong to the first or primitive forma, tion ; and those which lie highest up, or immediately at the surface, belong to the fourth or latest formation ; for the fifth formation includes only the volcanic matters, and of course is confined to particular spots. The names of the formations are as follow: I. Primitive. 2. Transition. 3. Floetz. -1. Al- luvial, 6. Volcanic. We are not to suppose, however, that the rocks be- longing to the primitive formation are always at a great depth below the sur- face. On the contrary, they frequently constitute mountains ; and the liighest mountains on the surface of the earth are composed of them. In these cases we must suppose the subsequent formations either never to have been deposited, or to have been removed and carried off by some unknown means. In like man- ner, the transition and floetz formations often constitute mountains, and appear ■t the surface ; and this must be accounted for in the same way. The primi. tive formation consists of rocks which follow others in sufcessieu ia the or. THE EARTH. 11(3 Others have fo'ond a different use for them, especially when they run surrounding our globe ; which is, that they stop the vapours that are continually travelling from the equator to the poles ; for these being lu-ged "by the heat of the sun, from the warm re- gions of the line, must all be accumulated at the poles, if they were not stopped in their way by those high ridges of mountains which cross their direction. But an answer to this may be, that ler of their names, beginning with the lowest. Tliese are as follow : 1. Gra- nite. 2. Gneiss. 3. Mica-slate, i. Clay-slate. 5. Porphyry and Sienite. Alternating with gneiss, mica-slate, and clay-slate, there occur beds of several other rocks, which being of no great extent compared with being frequently repeated, have been termed subordinate formations. These are primitive lime-stone, primitive trap, quartz, fluity-slate, and gypsum. Along with porphyry and sienite, occur serpentine and granite. Primitive rocks contain no petrifactions. They constitute the highest motintains on the face of the earth. They are evidently chemical compounds, and contain no minerals, which show themselves to have been mechanical depositions- They must have been formed before the earth was inhabited. The transU tion formation consists, likewise, of five classes of rocks, only one of which, namely, grei/ wacke, is peculiar to it, and characterises it. These rocks are as follow : Transition lime-stone. 2. Grey wacke, and grey wacke-slate. 3. Transition trap. 4. Transition fluity-slate. 5. Transitio:i gypsum. Pro. fessor Jameson has likewise discovered porphyry and granite among transi- tion rocks. These rocks contain petrifactions of animals and vegetables ; but they are of the lowest order, both of animals and vegetables, and generally consist of species which can be no longer found in a recent state. Hence these rocks must have been formed after the earth contained both animals and vegetables. ITie floetz formation occurs in a level country, and is usually covered by soil. As far as geological knowledge at present goes, it is known to consist of, 1. Sand-stone. Of this there are various formations; three, at least, have been ascertained. The lowest of aU is red, and distinguished by the name of old red sandstone. 2. Lime-stone. Of this also there are at least three forma- tions, if we include chalk, the position of which is not very well understood. 3. Floetz gypsum. Of this there are two formations, one of which is dis- tinguished by alternaf ug with rock-salt 4. Floetz-trap. This consists of green stone, and was first observed by Professor Jameson, in his examination of Dumfriesshire. 5. Independent coaL This formation, besides coal which characterises it, contains a variety of other rocks, iu beds chiefly sand-stone, greenstone, clay, iron-stone, lime-stone, and shale. 6. Newest floetz-trap. This formation generally caps the hills in those countries where it occurs. It consists of basalt, wacke, grey-stoue, porphyry-slate, green-stone, trap- tuff, clay-stone, sand-stone, &c. The floetz formations abound in petrifac- tions, and in mechanical depositions. Most of the metallic ores occur in the primitive and transition formations. The alluvial formation consists of the loose soil, gravel, sand, moss, &c. which cover the surface of the earth, and the volcanic formations consist of the ashes and lavas vomited out i>f Tolcauo'is. 104 HISTORY OP all the great mountains in America lie lengthwise, and therefore do not cross their direction. But to leave these remote advantages, others assert, that not only the animal but vegetable part of the creation would perish for want of convenient humidity, were it not for their friendly assist- ance. Their summits are, by these, supposed to arrest, as it were, the vapours which float in the regions of the air. Their large inflections and channels are considered as so many basons prepared for the reception of those thick vapours, and impetu- ous rains, which descend into them. The huge caverns beneath are so many magazines or conservatories of water for the. peculiar service of man -. and those orifices by which the water is dis- charged upon the plain, are so situated as to enrich and render them fruitful, instead of returning through subterraneous channels to the sea, after the performance of a tedious and fruitless cir- culation.' However this be, certain it is, that almost all our great riveri? find their source among mountains ; and, in general, the more extensive the mountain, the greater the i-iver ; thus the river Amazon, the greatest in the world, has its source among the Andes, which are the highest mountains on the globe ; the river Niger travels a long course of several hundred miles from the Mountains of the Moon, the highest in all Africa ; and the Danube and the Rhine proceed from the Alps, which are pro- bably the highest mountains of Europe. It needs scarcely be said, that, with respect to height, there are many sizes of mountains, from the" gently rising upland, to the tall craggy precipice. The appearance is in general different in those of different magnitudes. The first are clothed with verdure to the very tops, and only seem to ascend to improve our prospects, or supply us with a purer air: but the lofty moun- tains of the other class have a very different aspect. At a dis- tance their tops are seen, in wavy ridges, of the very colour of the clouds, and only to be distinguished from them by their figure ; which, as I have said, resembles the billows of the sea.' As we approach, the mountain assumes a deeper colour ; it gathers upon the sky, and seems to hide half the horizon behind it. Its summits also are become more distinct, and appear with 1 Nature Displayed, vol. iii. p. 88. 2 Lettres riiilosophiques sur la Formation, &c. p 1P& THE EAHTH. 105 a broken and perpendicular line. What at first seemed a single bill, is now found to be a chain of continued mountains, whose tops running along in ridges, are embosomed in each other : so that the curvatures of one are fitted to the prominences of the opposite side, and form a winding valley between, often of seve- ral miles in extent ; and all the way continuing nearly of the same breadth. Nothing can be finer, or more exact, than Mr Pope's descrip- tion of a traveller straining up the Alps. E very mountain he comes to, he thinks ^vill be the last ; he finds, however, an un- expected hill rise before him ; and that being scaled, he finds the highest summit almost at as great distance as before. Upon quitting the plain, he might have left a green and fertile soil, and a climate warm and pleasing. As he ascends, the ground assumes a more russet colour ; the grass becomes more mossy, and the weather more moderate. Still as he ascends, the weather becomes more cold, and the earth more barren. In this dreary passage he is often entertained with a little valley of surprising verdure, caused by the reflected heat of the sun col- lected into a narrow spot on the surrounding heights. But it much more frequently happens that he sees only frightful pre- cipices beneath, and lakes of amazing depths ; from whence rivers are formed, and fountains derive their original. On those places next the highest summits, vegetation is scarcely carried on ; here and there a few plants of the most hardy kind appear. The air is intolerably cold ; either continually refrigerated with frosts, or disturbed with tempests. All the ground here wears an eternal covering of ice, and snows that seem constantly ac- cumulating. Upon emerging from this war of the elements, he ascends into a purer and a serener region, where vegetation is entirely ceased; where the precipices, composed entirely of rocks, rise perpendicularly above him ; while he views beneath him all the combat of the elements ; clouds at his feet, and thunders darting upwards from their bosoms below.^ A thousand meteors, which are never seen on the plain, present themselves. Circu- lar rainbows ;* mock suns ; the shadow of the mountain pro- jected upon the body of the air ;* and the traveller's own image reflected as in a looking-glass, upon the opposite cloud.' 3 Ulloa, vol '■ 5 Phil. Trans, vol v. p. 153. i Ibid. 6 Ulloa, vol 106 HISTORY OF Such are, !n general, the wonders that present themselves to a traveller in his journey either over the Alps or the Andes. But we must not suppose that this picture exhibits either a con- stant or an invariable likeness of those stupendous heights. In- deed, nothing can be more capricious or irregular than the forms of many of them. The tops of some nin in ridges for a consi- derable length, wthout interruption ; in others, the line seems indented by great valleys to an amazing depth. Sometimes a solitary and a single mountain rises from the bosom of the plain ; and sometimes extensive plains, and even provinces, as those of Savoy and Quito, are found embosomed near the tops of moun- tains. In general, however, those countries that are most moim- tainous, are the most barren and uninhabitable. If we compare the heights of mountains with each other, we shall find that the greatest and highest are found under the line.' It is thought by some, that the rapidity of the earth's motion in these parts, together with the greatness of the tides there, may have thrown up those stupendous masses of earth. But, be the cause as it may, it is a remarkable fact, that the inequalities of the earth's surface are greatest there. Near the poles, the earth, indeed, is craggy and uneven enough ; but the heights of the mountains there are very inconsiderable. On the contrary, at the equator, where nature seems to sport in the amazing size of all her productions, the plains are extensive, and the mountains remarkably lofty. Some of them are knoM'n to rise three miles perpendicular above the bed of the ocean.* To enumerate the most remarkable of these, according to their size, we shall begin with the Andes, of which we have an excellent description by UUoa, who went thither by com. mand of the king of Spain, in company with the French Aca- demicians, to measure a degree of the meridian. His jouniey up these mountains is too curious not to give an extract from it After many incommodious days' sailing up the river Guayaquil, he arrived at Caracol, a town situated at the foot of the Andes. Nothing could exceed the inconveniences which he experienced in this voyage, from the flies and inoschetoes (an animal resem- bling our gnat). " We were the whole day," says he, " in con. 1 Buffon, passim. * See Plate iv. for a view of tlie absolute and relative heights of the most prominent mountains in the world. lUE EARTH. 107 tiniial motion to keep them off; but at night our torments were excessive. Our gloves, indeed, were some defence to our hands ; but our faces were entirely exposed ; nor were our clothes a sufll- cient defence for the rest of our bodies ; for tbeir stings pene- trating through the cloth, caused a very painful and fiery itching. One night, in coming to an anchor near a large and handsome bouse that was uninhabited, we had no sooner seated ourselve in it, than we were attacked on all sides by swarms of mosche- toes, so that it was impossible to have one moment's quiet. Those who had covered themselves with clothes made for this purpose, found not the smallest defence ; wherefore, hoping to find some relief in the open fields, we ventured out, though in danger of suffering in a more terrible manner from the serpents. But both places were equally obnoxious. On quitting this in- hospitable retreat, we the next night took up our quarters in a house that was inhabited ; the host of which being informed of the terrible manner we had past the night before, grasely told us, that the house we so greatly complained of, had been fore- saken on account of its being the purgatory of a soul. But we had more reason to believe that it was quitted on account of its being the purgatory of the body. After having journeyed for upwards of three days, through boggj- roads, in which the mules at eyery step sunk up to their bellies, we began at length to perceive an alteration in the climate ; and having been long accustomed to heat, we now began to feel it grow sensibly colder. " It is remarkable, that at Tariguagua we often see instances ■jf the effects of two opposite temperatures, in two persons hap. pening to meet : one of them leaving the plains below, and the other descending from the mountains. The former thinks the cold so severe, that he wraps himself up in all the garments h can procure ; while the latter finds the heat so great, that he i? scarce able to bear any clothes whatsoever. The one thinks the water so cold, that he avoids being sprinkled by it ; the other is so delighted with its warmth, that he uses it as a bath. Nor is he case very different in the same person, who experiences the dame diversity of sensation upon his journey up, and upon his retm'n. This difference only proceeds from the change naturally telt at leaving a climate to which one has been accustomed, and coming into anotbe.- of an opposite temperature. 108 HisjoRY or " The raggedness of the road from Teriguagua, leading up the mountain, is not easily described. In some parts the de clirity is so great, thnt the mules can scarcely keep their looting ; and in others, the acclivity is equally difficult. The trouble of having people going before to mend the road, the pains arising from the many falls and braises, and the being constantly wet to the skin, might be supported, were not these inconveniences augmented by the sight of such frightful precipices, and deep "bysses, as must fill the mind with ceaseless terror. There are s ome places where the road is so steep, and yet so narrow, that the mules are obliged to slide down, without making any use of their feet whatt>oever. On one side of the rider, in this situa- tion, rises an eminence of several hundred yards ; and on the other, an abyss of equal depth ; so that if he in the least checks his mule so as to destroy the equilibrium, they both must una- voidably perish. " After having travelled about nine days in this manner,' slowly winding along the side of the mountain, we began to find the whole country covered with a hoar frost ; and a hut, in which we lay, had ice on it. Having escaped many perils, we at length, after a journey of fifteen days, arrived upon the plain, on the extremity of which stands the city of Quito, the capital of one of the most charming regions upon earth. Here, in the centre of the torrid zone, the heat is not only very tolerable, but in some places the cold also is painful. Here they enjoy all the temperature and advantages of perpetual spring ; their fields being always covered with verdure, and enamelled with flowers of the most lively colours^ However, although this beautiful region be higher than any other country in the world, and al- though it took up so many days of painful journey in the ascent, it is still overlooked by tremendous mountains ; their sides covered with snow, and yet flaming mth volcanoes at the top. These seemed piled one upon the other, and rise to a most astonishing height, with great coldness. However, at a deter- mined point above the surface of the sea, the congelation is found at the same height in all the mountains. Those parts wtich are not subject to a continual frost, have here and there growing upon them a rush, resembling the genista, but much more soft and flexible. Towards the extremity of the part where the rush grows, and the cold begins to increase, is found a vege- THK EAUTH. 109 table, with a round bulbous head, which, when dried, l)ecomes of amazing elasticity. Higher up, the earth is entirely bare of vegetation, and seems covered with eternal snow. The most remarkable mountains ai'e, I'hat of Cotopaxi (already described as a volcano), Chimborazo, and Pichincha. Cotopaxi is more than three geographical miles above the surface of the sea : the rest are not much inferior. On the top of the latter was my station for measuring a degree of the meridian ; where I suffered parti- cular hardships from the intenseness of the cold, and the violence of the storms. The sky round was, in general, involved in thick fogs, which, when they cleared away, and the clouds, by their gravity, moved nearer to the surface of the earth, they appeared surrounding the foot of the mountain, at a vast distance below, like a sea, encompassing an island in the midst of it. When this happened, the horrid noises of tempests were heard from beneath, then discharging themselves on Quito, and the neigh- bouring country. I saw the lightnings issue from the clouds, and heard the thunders roll far beneath me. All this time, while the tempest was raging below, the mountain top, where I was placed, enjoyed a delightful serenity, the wind was abated; the sky clear ; and the enlivening rays of the sun moderated the severity of the cold. However, this was of no very long dura- tion, for the wind returned; w:ith all its violence, and with such velocity as to dazzle the sights whilst my fears w^re increased by the dreadful concussions of the precipice, and the fall of enormous rocks ; the only sounds that were heard in this fright- ful situation." Such is the animated picture of these mountains, as given us by this ingenious Spaniard : and I believe the reader w ill wish that I had made the quotation still longer. A passage over the Alj)S, or a journey across the Pyrenees, appear petty trips or excursions in the comparison ; and yet these are the most lofty mountains we know of in Europe. If we compare the Alps with the mountains already described, we shall find them but little more than one half of the height of the former. The Andes, upon being measured by the barome- ter, are found above three thousand one hundred and thirty-six ti/ises or fathoms above the surface of the sea.' Whereas the i Ulloa, vol. i. p. 442. 110 HUTOHY OF highest point of the Alps is not above sixteen hundred. The one, in other words, is above three miles high ; the otber about a mile and a half. The highest mountains in Asia are Mount Taurus, Mount Immaus, Mount Caucasus, and the mountains of Japan.* Of these, none equals the Andes in height; al- though Mount Caucasus, which is the highest of them, makes very near approaches. Father Verbiest tells of a mountain in China, which he measured, and found a mile and a half high.' In Africa, the mountains of the Moon, famous for giving source to the Niger and the Kile, are rather more noted than known. Of the Peak of Teneriffe, one of the Canary Islands that lie off this coast, we have more certain information. In the year 1727, it was visited by a company of English merchants, who travelled up to the top, where they observed its height, and the volcano on its very summit.* They found it a heap of moun- tains, the highest of which rises over the rest like a sugar-loaf, and gives a name to the whole mass. It is computed to be a mile and a half perpendicular from the surface of the sea. Kir. cher gives us an estimate of the heights of most of the other great mountains in the world j but as he has taken his calculations in general from the ancients, or from modern travellers, who had not the art of measuring them, they are quite incredible. The art of taking the heights of places by the barometer, is a new and an ingenious invention. As the air grows lighter as we ascend, the fluid in the tube rises in due proportion ; thus the instrument being properly marked, gives the height with n tolerable degree of exactness ; at least enough to satisfy cu- riosity. Few of our great mountains have been estimated in this man- ner ; travellers having, perhaps, been deterred, by a supposed impossibility of breathing at the top. However, it has been in- variably found, that the air in the highest that our modern tra- vellers have ascended, is not at all too fine for respiration. At the top of the Peak of Teneriffe, there was found no other in- convenience from the air, except its coldness ; at the top of the • The Himalaya Mountains between Hindostan and Thibet are ascert.iinert ti) be the highest in the world. The Andes were till a late period considered to be the highest, but the most elevated peak, yet measured, of the Himalaya exceeds that of the Andes about 7000 feet. I Verbiest, a la Chine. 2 Thil. Trans, vol. v THE EARTH. 1 1 » Andes, there was no difficulty of breathing perceived. Tl)« accounts, therefore, of those who have asserted that they were unable to breathe, although at much less heights, are greatly to be suspected. In fact it is very natural for mankind to pain^ those obstacles as insurmountable, which they themselves have not had the fortitude or perseverance to surmount. The difficulty and danger of ascending to the tops of mouii tains, proceeds from other causes, not the thinness of the air. For instance, some of the summits of the Alps have never yet Deen -vasited by man. But the reason is, that they rise with such a rugged and precipitate ascent, that they are utterly inac- cessible. In some places they appear like a great wall of six or seven hundred feet high ; in others, there stick out enormous rocks, that hang upon the brow of the steep, and every moment threaten destruction to the traveller below. In this manner almost all the tops of the highest mountains are bare and pointed. And this naturally proceeds from theii being so continually assaulted by thunders and tempests. Al. the earthy substances with which they might have been once covered, have for ages been washed away from their summits ; and nothing is left remaining but immense rocks, which no tem- pest has hitherto been able to destroy. Nevertheless, time is eveiy day, and every hour, making de- predations ; and huge fragments are seen tumbling down the precipice, either loosened from the summit by frost or rains, or struck down by lightning. Nothing can exhibit a more teirible picture than one of these enormous rocks, commonly larger than a house, falling from its height, with a noise louder than thun- der, and rolling down the side of the mountain. Doctor Plot tells us of one in particular, which beingloosened from its bed, tumbled down the precipice, and was partly shattered into a thousand pieces. Notwithstanding, one of the largest fragments of the same, still preserving its motion, travelled over the plain below crossed a rivulet in the midst, and at last stopped on the other side of the bank ! These fragments, as was said, are often struck off by lightning, and sometimes undermined by rains ; i)ut the most usual maimer in which they are disunited from the mountain, is by frost : the rains insinuating between the inter- t-oes of the mountain, continue there until there comes a frosts md then, \%hen converted into ice, the water swclln with an ir- K 2 112 IIISTOIIY OF resistible force, and produces the same effect as gunpowder, splitting the most solid rocks, and thus shattering the summits of the mountain. But Jiot rocks alone, but whole mountains are, by various causes, disunited from each other. We see in many parts of the Alps, amazing clefts, the sides of which so exactly corres- pond with the opposite, that no douht can be made of their hav- ing been once joined together. At Cajeta,' in Italy, a mouii- tiin was split in this manner by an earthquake ; and there is a passage opened through it, that appears as if elaborately done by the industry of man. In the Andes these breaches are frequent- ly seen. That at Thermopylte, in Greece, has long been famous. The mountain of the Troglodytes, in Arabia, has thus a passage through it : and that in Savoy, \\'hich nature began, and which Victor Amadeus completed, is an instance of the same kind. We have accounts of some of these disruptions, immediately after their happening. " In the month of June,^in the year 17 LI, a part of the mountain of Diableret, in the district of Valais, in France, suddenly fell down between two and three o'clock in the afternoon, the weather being very calm and serene. It was of a conical figure, and destroyed fifty-five cottages in the fall. Fifteen persons, together with about a hundred beasts, were also crushed beneath its ruins, which covered in extent a good league square. The dust it occasioned instantly covered all the neighbourhood in darkness. The heaps of rubbish were more than three hundred feet high. They stopped the current of a river that lan along the plain, which is now formed into several new and deep lakes. There appeared throug'i the whole of this rubbish none of those substances that seemed to indicate that this disruption had been by means of subterraneous fires. l\Iost probably, the base of this rocky mountain was rotted and decayed ; and thus fell, without any extraneous violence." In the same manner, in the year 1G18, the town of Pleurs, in France, was buried beneath a rocky mountain, at the foot of which is was situated.* 1 Buffon, vol. ii. p. 36t. 2 Hist, de I'Academie des Sciences, p. 4. An. 1715 X On tl!e 2d of September, 1806, an immense projection of the mountain « Rusfiherg in Switzerland gave way, and was precipitated into the valley lA Lowertz. In four mimites it completely overwhelined three villages, and part of two otliers. i'hc torrent of earth and Ktones v.as more rapid than THE EARTH. 1 13 These accidents, and majiy more that might be enumerated of the same kind, have been jjioduced by various causes : by earth- quakes, as in the mountain at Cajeta ; or being decayed at the bottom, as at Diableret. But the most general way is, by the foiHidation of one part of the mountain being hollowed by waters, and thus wanting a support, breaking from the other Thus it generally has been found in the great chasms in the Alps ; and thus it almost always is known in those disruptions of bills, which are knowTi by the name of land-slips. These are nothing more than the slidings down of a his/her piece of ground, disrooted from its situation by subterraneous inundations, and settling itself upon the plain below. that of lava, and its effects as impsistible and terrible. The mountain, in its tremendoas descent carried trees, rocks, houses, and every thing- before it. The mass spread in every direction, so as to bury, completely, a space of charming' country, more than three miles square. The force of the earth was so g-reat, that it not only overspread the hollow of the valley, but even ascended to a considerable height on the side of the opposite mountain. A portion of tlie falling mass rolled into the lake of Loxvertz, and it has be«n calculated that a fifth part of it is filled up. This event was nut caused by the fall of the summit of the mountain, but by an entire body pf layers, which, from the base, up to the summit of Kusfi- berg (being one hundred feet thick, one thousand feet wide, and nearly three miles in length), was separated from the lower layers, and slid parallel to their planes into the valley. Though this calamity was sudden, it had been pre- ceded several hours by certain indications which are of importance to re- cord, as they may at a future t;me induce people to escape from danger, and because they are the consequences of causes that determined the rapid ity with which the fallen part slid from its base. An inhabitant of Spitzbuhl, residing about two thirds up the mountain, heard amidst the rocks, about two o'clock, a kind of cracking, which he at- tributed to suptrnatural causes, and immediately ran down to Arth, to pro- cure a clergyman to come and quiet it. Almost at the same time, a man at the foot, of the mountai ., while striking his spade into the ground to dig up tome roots, saw the earth spirt up with a gentle explosion, and a kind of whizzing against his head. He left his work, and related this to his neigh- bours, for which phenomenon they could not account. The shepherds who still live in places intermediate to these two stations, assert that, from the morning and throughout the day, the mountain emitted a noise, accompanied with such agitation, that at the villages of St Anne and Arth, tituated .vithin twenty minutes' walk of the places laid waste, all the moveable goods in the houses staggered as if in a state of animation. The following is a summary of the li'Ss sustained : 434 individuals, IIH cows and horses, 103 goats and slieep dead ; eighty-seven meadows destroyed sixty meadows damaged, ninety-three houses entirely destroyed, eight houses damaged and uninhabitable, 16l iv. p. -ibO. THE EARTH. i L-5 ("0 descend, happen but very rarely. There are some ofanotijei kind, however, much more common ; and as they are always sudden, much more dangerous. These are snow-slips, well known, and greatly dreaded by travellers. It often happens that when snow has long been accumulated on the tops and on tlie sides of mountains, it is borne down the precipice, either by means of tempests, or its own melting. At first, when loosened, the volume in motion is but small ; but gathers as it continues to roll ; and by the time it has reached the habitable parts of the mountain, is generally grown of enormous bulk. "Wherever it rolls, it levels all things in its way, or buries them in unavoid- able destruction. Instead of rolling, it sometimes is found to slide along from the top ; yet even thus it is generally as fatal as before. Nevertheless, we have had an instance, a few years ago, of a small family in Germany, that lived for above a fort- night beneath one of these snow-slips. Although they were buried during that whole time in utter darkness, and under a bed of some hundred feet deep, yet they were luckily taken out alive; the weight of the snow being supported by a beam that kept up the roof; and nourishment being supplied them by the milk of an ass, if I remember right, that was buried under the same ruin. But it is not the parts alone that are thus found to subside, whole mountains have been known totally to disappear. Pliny tells us,* that in his own time the lofty mountain of Cybotus, together with the city of Eurites, were swallowed by an earth- quake. The same fate, he says, attended Phlegium, one of the highest mountains in Ethiopia ; which after one night's con- cussion \Nas never seen more. In more modem times, a very noted mountain in Jie Molucca islands, known by the name of the Feak, and remarkable for being seen at a very great distance from sea, was swallovi'ed by an earthquake ; and nothing but a ike was left in the place where it stood. Thus, while storms und tempests are levelled against mountains above, earthquakes and waters are undermining them below. All our histories talk of their destruction ; and veiy few new ones (if we except mount Cenere, and one or two such heaps of cinders,) are pro- duced. If mountains, therefore, were of such great utility as 2 I'lin. lib. iL cap. 93. 116 HISTORY Ol »rnie philosophers make them to maiikind, it would be a very melancholy consideration that such benefits were diminishing every day. But the truth is, tne valleys are fertilized by that earth which is washed from their sides ; and the plains become richer, in proportion as the mountains decay. CHAP. XIII. OF WATER. In contemplating nature, we shall often find the same sub- stances possessed of contrary qualities, and producing opposite effects. Aw which liquefies one substance, dries up another. That fire which is seen to burn up the desert, is often found in other places, to assist the luxuriance of vegetation ; and water which, next to fire, is the most fluid substance upon earth, nevertheless gives all other bodies their firmness and durability ; so that every element seems to be a powerful servant, ca|)able either of good or ill, and only awaiting external direction to become the friend or the enemy of mankind. These opposite qualities, in this substance in particular, have not failed to excite the admiration and inquiry of the curious. That water is the most fluid penetrating body, next to fu-e, and the most difficult to confine, is incontestably proved by a vari ety of experiments. A vessel through which water cannot pass, may be said to retain any thiiig. It may be objected indeed, that syrups, oils, and honey, leak through some vessels that water caimot pass through ; but this is far from being the result of the greater tenuity and fineness of their parts j it is owing to the rosin wherewith the wood of such vessels abounds, which oils and syrups have a power of dissolving ; so that these fluids, instead of finding their way, may more properly be said to eat their way, through the vessels that contain them. However, water will at last find its way even through these; for it is known to escape through vessels of every substance, glass only excepted. Other bodies may be found to make their way out more readily indeed ; as air, when it finds a vent, will escape at once; and (]uicksi]vr are made to pass through a red hut iron tube, 15 parts of hy- drogen gas vv II be procured, while the inside of the tube will be fooud coo. v«rted into au oxyd, and to have gained S5 parts in weight TH£ EAKTH, 119 most genuine we know is mixed with exhalations and dissolu- tions of various kinds ; and no expedient that has been hitlier- to discovered, is capable of purifying it entirely. If we filter and distil it a thousand times, according to Boerhaave, it will still deposit a sediment ; and by repeating the process we may eva- porate it entirely away, but can never totally remove its impuri- ties. Some, however, assert, that water, properly distilled, will have no sediment-' and that the little white speck which is found at the bottom of the still, is a substance that enters from without. Kircher used to show, in his Museum, a phial of .\'ater that had been kept for fifty years, hermetically sealed ;* during which it had deposed no sediment, but continued as trans- parent as when first it was put in. How far, therefore, it may be brought to a state of purity by distillation, is unknown ; but he very well know, that all such water as we every \vhere see, is a bed in which plants, minerals, and animals, are all found confusedly floating together. Rain-water, which is a fluid of Nature's own distilling, and which has been raised so high by evaporation, is nevertheless u very mixed and impure substance. Exhalations of all kinds, whether salts, sulphurs, or metals, make a part of its substance, and tend to increase its weight. If we gather the water that falls, after a thunder-clap, in a sultry summer's day, and let it settle, we shall find a real salt sticking at the bottom. In win. ter, however, its impure mixtures are fewer, but still may be separated by distillation. But as to that which is generally caught pouring from the tops of houses, it is particularly foul, being impregnated with the smoke of the chimneys, the vapour of the slates or tiles, and with other impmities that birds and animals may have deposited there. Besides, though it should be supposed free from all these, it is mixed with a quantity of air, which, after being kept for some time, wiU be seen to 6e])arate. Spring- water is next in point of purity. This, according to Dr Halley, is collected from the air itself; which being sattid 1 Hill's History of Fossils. 2 Hermetically sealing a glass vessel, means no more than heating tlio mouth of the phial red hot ; and thus when the glass is become pliant, squeez- ing the mouth together uitli a (tair of pincers, and then twisliug it six ot Eevtrn timea round, which etiectually closes it up. 120 insrouY of with water, and coming to be condensed by the evening's cold, is driven against the tops of the mountains, where being condensed and collected, it trickles down by the sides, into the cavities of the earth ; and running for a while underground, bubbles up in fountains upon the plain. This having made but a short circu- lation, has generally had no long time to dissolve or imbibe any foreign substances by the way.* • The cause of springs is, that the water which falls on the surface of the earth, in rain, snow, &e. penetrates its substance till it meets with a stratum of clay, stone, or some otlier matter which stops its descent; it then glides laterally on the stratum which sustains it, and in the direction to « hich it leans, till meeting with an aperture, it appears on tlie surface of the earth iii the form of a spring. As water always has a tendency to descend, springs Hte always lower tlian the source from which they are supplied :— Springs ai-e most common on the sides and at the bottom of mountains ; they are BPldom found quite at the summit of a mountain, and are rare where acoun- try is every where level to a considerable distance, because there the strata are parallel, and do not coudtK-t the water to any particular point. In order to obtain water therefore in flat countries, it is in general necessary to dig Into the earth, where it is found to flow copiously from the sides of the open- ing, at no great distance from the surface. When wells are dug in elevated Kituationa, water is seldom met with till we have dug to a considerable depth, and got below the general level of the country. There are some springs which exhibit a very curious phenomenon, a kind of tide or intermission by which the water at certain periods appears to rise a considerable height, and gradually to subside. Tliese are called IntermitUng Springs. Others have a periodical swell, and discharge a greater quantity of water at one time than at another, the changes taking place at equal inter- vals. These are called Reciprocating Springs. It was long imagined that these fountains were replenished by some connection with the sea; that the water was freshened by its progress througli sand and earth, and their rising and falling depended on the tide. It was, however, found, that the periods of the water rising and falling in these springs, did not correspond in point of time with the tides of the adjacent seas, and that the periods were dif- ferent in difterent springs, contrary to the regular rising and falling of the tides of the ocean. The phenomenon has since been satisfactorily explained The first of these kind of springs is very easily accounted for, by supposing the channel which carries the water off from a cavern to have the form of a siph on. In this case the water wUl only flow when it rises in the cavern to a height equal to that of the upper curve of the siphon-formed canal, and it will fill again wnen it descends below it. The following explanation of the second kind of intermitting springs was suggested about a century back by Dr At- well, of Oxford, by attending to the p'.ienomena of Lay well spring, at Brixam, n.ar Torbay, in Devcmsliire. Let A A (plate iii. fig. 4.) be a large cavern near the tup of a hill, which derives its supply of water from the rains or melted snow filtering through the crevices of the mountains ; and let CC re- present the small channel which conveys the waters of the cavern to the ■■■>'>niu.; G in the hill, wiioe they are discharged iu thefurmof aimall epririi;. THE EARTH. 121 River-water is generally more foul than the former. — Where- ever the stream flows, it receives a tincture from its channel. Plants, minerals, and animals, all contribute to add to its im- purities : so that such as live at the mouths of great rivers, are generally subject to all those disorders which contaminated and unwholesome waters are known to produce. Of all the river- water in the world, that of the Indus and the Thames is said to be the most light and wholesome. The most impure fresh water that we know, is that of stag nating pools and lakes, which, in summer, may be more pro- perly considered as a jelly of floating insects, than a collection of water.* In this, millions of little reptiles, undisturbed by any current, which might crush their frames to pieces, breed and en- gender. The whole teems with shapeless life, and only grows more fiaitfol by increasing putrefaction. Of the purity of all these waters, the lightness, and not the transparency, ought to be the test. Water may be extremely clear and beautiful to the eye, and yet very much impregnated with mineral particles. In fact, sea-water is the most transpa- rent of any, and yet it is well kno\m to contain a large mixture of salt and bitumen. On the contrary, those waters which are lightest, have the fewest dissolutions floating in them ; and may, therefore, be the most useful for all the purposes of life. But, after all, though much has been said upon this subject, and although waters have been weighed with great assiduity, to determine their degree of salubrity, yet neither this, nor their curdling From the cavern A A let there be a small channel D, which carries water into another cavern B, and conceive the water ia the second cavern to be carried ofif by a bent chpunel E e F, wider than D, and joining tlie first chan. nel CC at/, before it issues fmra the mountain, the point of junction/being below the level of the bottoms of both the caverns. Then as the cavern 15 fills with water, the fluid will ascend to the same height in the channel E e F, but it will not be discharged bj- it till the surface in B is on a level with e, the highest part of the channel. The water will then be carried off by the natu. ral siphon E e F G, till the whole is discharged, and consequently there will Lre a great swell iu the spring at G. This spring will now cease, because th channel D does not convey the water into B so fast as the siphon E e F car. ries it off, and it will again commence as soon as the water in B rises to a Sevel with the summit e. A machine for illustrating these pheaomeoa is described by Ferguson in his Lectures, vol. it p. 106. >■ \ quantity of charcoal thrown into putrid'water renders the water Bwect in ? few hoursu 1. 122 . HISTORY OF with soap, nor any other philosophical standard whatsoever, will answer the purposes of true information. Experience alone ought to determine the useful or noxious qualities of every spring ; and experience assures us, that diiferent kinds of water ere adapted to different constitutions. An incontestible prooi of this, are the many medicinal springs throughout the vvorld, whose peculiar benefits are known to the natives of their respec- tive countries. These are of various kinds, according to the dif- ferent minerals with which they are impregnated ; hot, saline, sulphureous bituminous, and oily.* But the account of these ♦ Mineral waters are divided into four classes, the acidulous, the sulphu- reous, the chnlybeate, and the saline. Acidulous waters are those which contain carbonic acid in its free state, oi In combination in excess Witt a base. These waters are easily disting'uished by their slightly acid taste, and by their sparklinff when poured from one vesse. to another ; both of which properties they lose, when exposed to the air for a length of time, or by boiling. Besides carbonic acid, they almost always contain muriate of soda, and some of the earthy carbonates ; it. is the frea carbonic acid, however, that imparts to them their particular properties. Sulphureous tvaters are those which contain sulphuretted hydroijeii. Thesa are very easily distinguished by their odour, and by their renderiuga solution of a salt of lead black, or by causing a piece of silver, when immersed in thi'm, to acquire a dark colour. Besides sulphuretted hydrogen, they in general contain alkaline fgjd earthy sulphates and muriates. The sulphureous wa- ters may be subdivided into two kinds ; 1st, Those which have sulphuretted hydrogen in its free state ; 2d, Those in which it exists in union with an alkali or an earth. Chali/heiite Ttaters are those which have iron as an ingredient. These are known by their peculiar taste, and by their becoming black when mixed with an infusion of nutgalls. The chalybeate waters are of different kinds ; some- times the iron is combined with sulphuric acid, more frequently it is in union with carbonic acid; this may be just in sufficient quantity to hold the iron in solution, or it may be in excess, in which case, besides chalybeate, the water possesses acid properties, forming what is called an acidulous chalybeate water. Saline waters are those which contain the saline ingredients generally found in mineral waters, but which have not carbonic acid in excess, and are free from sulphuretted hydrogen and iron, or contain them in very trifling quantity. Saline waters may be subdivided into four kinds, viz. : — Alkaline waters, or those which contain alkali in its free state, or combined with car. bonic acid, and which render the vegetable blues green. Hard waters, or those which contain carbonate or sulphate of lime. Salt waters, or those in which muriate of soda abounds. Purgative waters, or those which contaifl principally sulphate of magnesia. Hot springs are most frequent in volcanic regions. Mo satisfactory ex- planation of the temperature of these springs, and, above all, of their won. derful equability in thio /aspect, for a very long series of years, has ever been THE EARTH. 123 will come most properly under that of the several minerals I'Y which tbey are produced. After all, therefore, we must be contented with but an im- pure mixture of our daily beverage. And yet, perhaps, this very mixture may often be more serviceable to our health than offered. Wlien they are connected with volcanoes, we naturally ascribe tJie temperature of thet spring to the heat of the volcano ; but when they occur Rt a considerable distance from volcanic countries, such an explanation can- not be applied. Thus, the hot spring at Bath, has continued at a tempera, ture higher than that of the air, for a period not less than 2000 years ; yet it is so far from any volcano, that we cannot, without a very violent and im- probable extension of volcanic fires, ascribe it to their energy. There ara various decompositions of mineral bodies, which generate considerable heat These decompositions are generally brought about by means of water; or to speak more properly, water is itself the substance which is decomposed, and which generates heat by its decomposition. Thus, for example, there are varieties of pyrites, which are converted into sulphate of iron by the contact of water, and such a change is accompanied by an evolution of heat. Were we to suppose the Bath spring to flow through a bed of such pyrites, its heat might be occasioned by such a decomposition. Such probably is the way in which those springs, that contain sulphurated hydrogen ga-s, receive their impregnation. But we are pretty certain, that such a supposition will not apply to Bath water : first, because it does not contain the notable quantity of sulphate, or iron, which would be necessary upon such a supposition ; and, secondly, because instead of sulphurated hydrogen gas, which would infalli. bly result from such a decomposition of pyrites, there is an evolution of azotic gas. This evolution of azotic gas, however, is a decisive proof that the heat of Bathwater is owing to some decomposition or other which takes place witliin the surface of the earth; though from our imperfect acquaintance with the nature of mineral strata, through which the water flows, we cannot give any satisfactory information about what that decomposition actually is In the island of St Miguel, one of the Azores, wliich exhibits, acc.irding to Mr Masson, very obvious marks of having abounded in volcanoes, there are R considerable number of hot springs of various temperatures ; some boiling hot, others cooler, and some so low that they are used as baths, and have ac- quired great celebrity for the wonderful cures they have performed. Mr Masson informs us, that these springs are surrounded with abundance of na. live sulphur, which, he affirms, is exhaled by them in abundance a circum. stance which renders it probable, that the heat of these springs depends upon the decomposition of pyrites. In the island of Amsterdam there are several hot springs ; in one of them was immersed Fahrenheit's Thermometer, which in the air stood at sixty- two degrees, and it ascended immediately to 19S0. In another it rose 204» ■ mid the bulb of the thermometer being applied to a crevice, ascended in less than a minute to the boiling point. Some fish being caught and put into the f pring, were boiled 8t for eating in 15minute3. In the island of Iceland there ore many hot springs, and several magnificent spouting springs, which ara called Geysers 1^2 121 HISTOIIY OF that of a purer kind. We know that it is so with regard to vegetables : and why not, also, in general, to man ? Be this as- it will, if we are desirous of having water in its greatest purity, we are ordered, by the curious in this particular, to distil it from snow, gathered upon the tops of the highest mountains, and to take none but the outer and superficial part thereof. This we must be satisfied to call pure water ; but even this is far short of the pure unmixed philosophical element ; wliich, in reality, is nowhere to be found. As water is thus mixed with foreign matter, and often the re- pository of minute animals, or vegetable seeds, we need not be .surprised that, when carried to sea, it is always found to putrefy. But we must not suppose that it is the element itself which thus grows putrid and oifensive, but the substances with which it is impregnated. It is true, the utmost precautions are taken to destroy all vegetable and animal substances that may have pre- viously been lodged in it, by boiling ; but, notwithstanding this, there are some that will still survive the operation, and others that find their way during the time of its stowage. Seamen, therefore, assure us, that their water is generally found to putre- fy twice, at least, and sometimes three times, in a long voyage. In about a month after it has been at sea, when the bung is taken out of the cask, it sends up a noisome and dangerous vapour, which would take fire upon the application of a candle.' The whole body of the water then is found replete with little worm- like insects, that float, with great briskness, through all its parts. These generally live for about a couple of days ; and then dying, by depositing their spoils, for a while increase 4:he putrefaction. After a time, the heavier parts of these sinking to the bottom, the lighter float in a scum, at the top ; and this is what mariners call the water's purging itself. There is still, however, another race of insects, which are bred, very probably, from the spoils of the former ; and produce, after some time, similar appearances : these dying, the water is then thought to change no more. How. ever, it very often happens, especially in hot climates, that no- thing can drive these nauseous insects from the ship's store or water. They often increase to a very disagreeable and frightful gize, so as to deter the mariner, though parching with thirst, from tasting that cup which they have contaminated. 1 Phil. Trans, vol. v. part ii. p. 71 THt EAaTH. 125 This water, as thus described, tlierefore, is a very different fluid from that simple elementary substance upon which philo- Bophical theories have been founded ; and concerning the nature of which there have been so many disputes. Elementary water is no way compounded ; but is without taste, smell, or colour ; and incapable of being discerned by any of the senses, except the touch. This is the famous dissolvent of the chymists, into which, as they have boasted, they can reduce all bodies; and which makes up all other substances, only by putting on a dif- ferent disguise. In some forms, i*- is fluid, transparent, and evasive of the touch ; in others, hard, firm, and elastic. In some, it is stiffened by cold ; in others, dissolved by fire. Ao- rording to them, it only assumes external shapes from acciden- tal causes ; but the mountain is as much a body of water, as the 9ake of ice that melts on its brow ; and even the philosopher himself is composed of the same materials with the cloud or meteor which he contemplates. Speculation seldom rests when it begins. Others, disallow- ing the universality of this substance, will not allow that in a state of nature there is any such thing as water at all. " What assumes the appearance," say they, " is nothing more than melt- ed ice. Ice is the real element of Nature's making ; and when found in a state of fluidity, it is then in a state of violence. All substances are naturally hard ; but some more readily melt with heat than others. It requires a great heat to melt iron •, a smaller heat will melt copper ; silver, gold, tin, and lead, mell with smaller still-, ice, which is a body like the rest, melts with a very moderate warmth ; and quicksilver melts with the smallest warmth of all. Water, therefore, is but ice kept in :;ontinual fusion ; and still returning to its former state, when the heat is taken away." Between these opposite opinions, the controversy has been carried on v\ith great ardour, and much has been written on both sides ; and yet when we come to ex- amine the debate, it will probably terminate in this question, whether cold or heat first began their operations upon water' This is a fact of very little importance, if known ; and, what is more, it is a fact we can never know. Indeed, if we examine into the operations of cold and heat upon water, we shall find that they produce somewhat similar effects. Water dilates in its bulk, by heat, to a very consider. I, -S I2G HISTORY OP able degree ; and, what is more extraordinary, it is likewise di- lated by cold in the same manner. If water be placed over a fire, it grows gradually larger in !>ulk, as it becomes hot, until it begins to boil ; after which no art can either increase its bulk or its heat. By increasing the fire, indeed, it may be more quickly evaporated away ; but its heat and its bulk still continue the same. By the expanding of this fluid, by heat, philosophers have found a way to deter- mine the warmth or the coldness of other bodies ; for if put into a glass tube, by its swelling and rising, it shows the quantity of heat in the body to which it is applied ; and by its contracting and sinking, it shows the absence of the same. Instead of using water in this instrument, which is called a thermometer, they now make use of spirit of wine, which is not apt to freeze, and which is endued even with a greater expansion, by heat, than water.* The instrument consists of nothing more than a hol- « Mercury expands by heat and contracts by cold with greater uniformity than even spirit of wine : it is therefore the most proper and the most com. nionly used fur thermometers. There are four different thermometers used at present in Europe ; these are, Fahrenheit's, Celsius's, Reaumur's, and De Lisle's. Fahrenheit's thermometer is used in liritain. The space between tlie boiling and freezing points is divided into ISOo; but the scale begins at the temperature produced by mixing together snow and common salt, which is 32' below the freezing point ; of course the freezing point is marked 320, and tlie boiling point 212o. The thermometer of Celsius is used in Sweden ; it' has been used also in France since the first revolution, under the name of the thermometre centi- grade. In it the space between the freezing and boiling points, is divided into lOlJO. The freezing point is marked 0, the boiling point lOOo. Ihe thermometer known by the name of Reaumur, which was in fact constructed by De Luc, ivas used in France before the revolution, and is still used in Italy and Spain. In it the space between the boiling and freezing points is divided into 80o. The freezing point is marked 0, the boiling point Sf!0. De Lisle's thermometer is used in Russia. The space between the boiling and freezing points is divided into 1500; but the gradation begins at the boiling point, and increases towards the freezing point. The boiling point is marked 0, and the freezing point 130o. The temperatures which we can measure by a mercurial thermometer are confined within narrow limits. For mercury freezes at about .IQ* below zero, and boils at G60o. Hence we cannot employ it to. measure greater heats than 6*J0!>, nor greater degrees of cold than Syo. Yet many temperatures connected •vit!! our most common processes are much Iiigher than GGOu. The heat of a common fire, the temperature at which silver, copper, and gold melts, and many oUier such points, offer familiar examples. — See Dr Thomson's " Out- ine of the Science of Heat and Electiicity," IS30, 8vo. THE F.AUTU. 127 low ball of glass, with a long tube growing out of it. This being partly filled with spirits of wine tinctured red, so as to be seen when it rises, the ball is plunged into boiling water, which making the spirit within expand and rise in the tube, the water marks the greatest height to which it ascends ; at this point the tube is to be broken off, and then hermetically sealed, by melt- ing the glass with a blow-pipe : a scale being placed by the side, completes the thermometer. Now as the fluid expands or con. denses with heat or cold, it will rise and fall in the tube in pro- portion : and the degree or quantity of ascent or descent wiU be seen in tlie scale. No fire, as was said, can make water hotter, after it begins to boil. We can, therefore, at any time be siu-e of an equable cer- tain heat ; which is that of boiling water, which is invariably the same. The certainty of such a heat is not less useful than the instrument that measures it. It affords a standard, fixed degree of heat over the whole world; boiling water being as hot in Greenland as upon the coast of Guinea. One fire is more in- tense than another ; of heat there are various degrees ; but boiling water is a heat every where the same, and easily pro- ciu"able. As heat thus expands water, so cold, when it is violent enough to freeze the same, produces exactly the same effect, and ex- pands it like\dse. Thus water is acted upon in the same man- ner by two opposite qualities; being dilated by both. As a proof that it is dilated by cold, we have only to observe the ice floating on the surface of a pond, which it would not do were it not dilated, and grown more bulky, by freezing, than the water which remains unfroze. ]\Ir Eoyle, however, put the matter past a doubt, by a variety of experiments.' Having pomed a proper quantity of water into a strong earthen vessel, he ex- posed it, uncovered, to the open air, in ft-osty nights ; and ob- served, that continually the ice reached higher than the watei before it was frozen. He filled also a tube with water, arid stopped both ends with wax : the water, when frozen, was found to push out the stopples from both ends; and a rod of ice appeared at each end of the tube, which showed how much it was swollen by the cold within. I Boyle, vol. J. p. 610. 128 KISTOUV OF From hence, therefore, we may be very certain of the cold dilating the water; and experience also shows, that the force of this expansion has been found as great as any which heat has been found to produce. The touch-hole of a strotig gun-barrel being stopped, and a plug of iron forcibly driven into the muzzle, after the barrel had been filled with water, it was placed in a mixture of ice and salt ; the plug, though soldered to the barrel^ iit first gave way, but being fixed in more firmly, within a quar- ter of an hour the gun-barrel burst with a loud noise, and blew up the cover of the box wherein it lay. Such is its force in an ordinary experiment. But it has been known to burst cannons, filled with water, and then left to freeze ; for the cold congealing the water, and the ice swelling, it became irresistible. The bursting of rocks by frost, which is frequent in the northern climates, and is sometimes^ seen in our own, is an equal proof of the expansion of congealed water. For having by some means insinuated itself into the body of the rock, it has remain- ed there till the cold was sufficient to eflfect it by congelation. But when once frozen, no obstacle is able to confine it from dilating ; and, if it cannot otherwise find room, the ruck must burst asunder This alteration in the balk of water might have served as a proof tliat it was capable of being compressed into a narrower space than it occupied before ; but, till of late, water was held to be incompressible. The general opinion was, that no art whatsoever could squeeze it into a narrower compass ; that no power on earth, for instance, could force a pint of water into a vessel that held an hair's-breadth less than a pint. And this, said they, appears from the famous Florentine experiment; whei-e the M'ater, rather than suffer a compressure, was seen to ooze through the pores of the solid metal ; and, at length, mak ing a cleft in the side, spun out with great vehemence. But later trials have proved that water is very compressible, and partakes of that elasticity which every other body possesses in some degree. Indeed, had not mankind been dazzled by the brilliancy of one inconclusive experiment, there were numerous reasons to convince them of its having the same properties with other substances. Ice, which is water in another state, is very elastic. A stone, flung slantingly along the surface of a pond, bounds from the water several times ; which shows it to he THE EARTH. 120 <>' astic also. But the trials of Mr Canton have put this past all doubt ; which being somewhat similar to those of the great Boyle, who pressed it with weights properly applied, carry suffi cient conviction.* * With the barometer at 2tfi, and thermometer at 50, Canton declares l!.. foUowiug to be the results he obtained : Cteipression of spirit of wine . . . 66 parts la a million. Oil of olives ... 48 ditto. Rain-water . . . . 4<5 ditto. Sea-water .... 40 ditto. Mercury . ... 3 ditto. These results he obtained in the following manner : He took a glass tuoe about two feet long, with a ball at one end, of an inch and a qiuirter in dia- meter ; he filled the ball, and part of the tube, with water which had pre- Tiously been deprived of air as much as possible ; he then placed it under tlm rpceiverof an air pump, and removed fromitthe pressure of the atmosphere; under this treatment he observed that the water rose a little way in the tube. On the contrary, when he placed the apparatus upon a condensing engine, and by condensing the air in the receiver, increased the pressure upon the water^ lie observed that the water descended a little way in the tube. In this man. ner he found that water expanded one part in 21,740 when the pressure of the atmosphere was removed, and submitted to a compression of one part in 10,870 under the weight of a double atmosphere. He also observed that water possessed the remarkable property of being more compressible in winter than in summer ; contrary to the effect on spirit of wine and oil of olives. Lest it might be supposed that the comi)ressibility thus discovered might be owing to air lodged within the fluids employed, a quantity of water was caused to imbibe more air than it contained in a preceding trial ; but its compressibility was not increased. These experiments, although upon th e whole so apparently decisive of the questions they were instituted to deter- mine, are yet not to be received without some caution ; and in particular, the remark that the addition of a portion of so compressible a fluid as r.ir, did not render water more compressible than before, is rather staggering, and is calculated to throw the veil of doubt over all the rest. It remains therefore, for future investigation to fix the judgment of philosophers dd this preposterous concern to the number. That air also contributes to divide the parts of water, we can have no manner of doubt ; some have even disputed whether water be not capable of being turned into air. However, though this cannot be allowed, it must be granted, that it may be turn- ed into a substance which greatly resembles air (as we have seen !n the experiment of the seolipile) with aU its properties ; except that, by cold, this new-made air may be condensed again into water. But of all the substances which tend to divide the parts of water, fire is the most powerful. Water, when heated into steam, acquires such force, and the parts of it tend to fly oflf from each other with such violence, that no earthly substance we know of is strong eiiough to confine them. A single drop of water, converted into steam, has been found capable of raising a weight of twenty tons ; and would have raised tvventy thou- sand, were the vessel confining it suiBciently strong, and the fire below increased in proportion. From this easy yielding of its parts to external pressure, arises the art of determining the specific gravity of bodies by plunging them in water ; with many other useful discoveries in that part of natural philosophy, called hydrostatics. The laws of tins science, which Archimedes began, and Pascal, with some other of the moderns, have much improved, rather belongs to experi- mental than to natural history. Hosvever, I will take leave to mention some of the most striking paradoxes in this branch of 132 HISTORY OF .science, which are as well confii-med by ex|)eiiment, as rendered universal by theory. It would, indeed, be unpardonable, while discoiu-sing on the properties of water, to omit giving some ac- count of the manner in which it sustains such immense bulks, as we see floating upon its soft and yielding surface ; how some bodies, that are known to sink at one time, swim with ease, if their surface be enlarged ; how the heaviest body, even gold it- self, may be made to swim upon water : and how the lightest, such as cork, shall remain sunk at the bottom; how the pouring in of a single quart of water, will burst a hogshead hooped with iron : and how it ascends, in pipes, from the valley, to travel over the mountain ; these are circumstances that are at first sur prising ; but, upon a slight consideration, lose their wonder. ' In order to conceive the manner in which all these wonders are effected, we must begin by observing that water is possessed of an invariable property, which has not hitherto been mentioned, that of alvvays keeping its surface level and even. Winds, in- deed, may raise it into waves, or art spurt it up in fountains ; but ever, when left to itself, it sinks into a smooth even surface, of which no one part is higher than another. If I should pour water, forinstance, into the arm of a pipe of theshape of the letter U, the fluid would rise in the other arm just to the same height ; be- cause, otherwise, it would not find its level, which it invariably maintains. A pipe bending from one hUl down into the valley, and rising by another, may be considered as a tube of this kind, in which the water, sinking in one arm, rises to maintain its level in the other. Upon this principle all water pipes depend ; which can never raise the water higher than the fountain from which they proceed. Again, let us suppose for a moment, that the arms of the pipe already mentioned, may be made long or short at pleasure •, and let us still further suppose, that there is some obstacle at the bottom of it which prevents the water pouring into one arm, from rising in the other. Now it is evident, that this obstacle at the bottom will sustain a pressure from the water in one arm, equal to what would make it rise in the other ; and this pressure ) In the above sketch, the manner of demonstrating- used by Monsieur D'Alembertis made use of, as the most obvious, and the most satisfactory. Vide Essai sar, &c. THE EARTH. 1.33 wiil be great, in proportion as the arm filled with water is talL We may, therefore, generally conclude, that the bottom of every vessel is pressed by a force, in proportion to the height of the water in that vessel. For instance, if the vessel filled with water be forty feet high, the bottom of that vessel will sustain such a pressure as would raise the same water forty feet high, which IS very great. From hence we see how extremely apt our pipe?, that convey water to the city, are to burst; for descending from a hill of more than forty feet high, they are pressed by the water contained in them, with a force equal to what would raise it to m.ore than forty feet high ; and that this is sometimes able to burst a wooden pipe, we can have no room to doubt of. Still recurring to our pipe, let us suppose one of its arms ten times as thick as the other ; this will produce no effect whatso- ever upon the obstacle below, which we .supposed hindering its rise m the other arm ; because, how thick soever the pipe may be, its contents would only rise to its own level ; and it will, there- fore, press the obstacle with a force equal thereto. We may, therefore, imiversally conclude, that the bott.im of any vessel is pressed by its water, not as it is broad or narrow, but in propor- tion as it is high. Thus the water contained in a vessel not thicker than my finger, presses its bottom as forcibly as the water contained in a hogshead of an equal height ; and, if we made holes in the bottoms of both, the water would burst out as forceful from the one as the other. Hence we may, with great ease, burst a hogshead vrith a single quart of water ; and it has been often done. We have only,' for this, to place a hogshead on one end, filled with water : we then bore a hole in its top, into which we plant a narrow tin pipe, of about thirty feet high : by poiuing a quart of water into this, at the top, as it continues to rise higher in the pipe, it will press more forcibly on the bottom and sides of the hogshead below, and at last burst it- Still returning to our simple instrument of demonstration. If we suppose the obstacle at the bottom of the pipe to be move- able, so as that the force of the water can push it up into the other arm ; such a body as quicksilver, for instance. Now, it is evident, that the weight of water weighing down upon this 2 NoUet's Lectures. tSii HISTORY OF quicksilver in one a\fn, will at last press it up in the othei arm ; and will continue to press it upwards, until the fluid in both arms be upon a par. So that here we actually see quicksilver, the heaviest substance in the world, except gold and platiiia, tloating upon water, which is but ti very light sub- stance. When we see water thus capable of sustaining quicksilver, we need not be surprised that it is capable of floating much lighter substances, ships, animals, or timber. When any thing floats upon water, we always see that a part of it sinks in the same. A cork, a ship, a buoy, each burits itself in a bed on the surface of the water ; this bed may be considered as so much v/ater dis- placed ; the water will, therefore, lose so much of its own weight, as is equal to the weight of that bed of water which it displaces. If the body be heavier than a similar bulk of water, it will sink ; if lighter, it will swim. Universally, therefore, a body plunged in water, loses as much of its weight as is equal to the weight of a body of water of its own bulk. Some light bodies, therefore, such as cork, lose much of their weight, and therefore swim ; other more ponderous bodies sink, because they are heavier than their bulk of water. Upon this simple theorem entirely depends the art of weigh- ing metals hydrostatically. I have a guinea, for instance, and desire to know whether it be pure gold ; I have weighed it in the usual way with another guinea, and tind it exactly of the same weight, but still I have some suspicion, from its greater bulk, that it is not pure. In order to determine this, I have nothing more to do than to weigh it in water with that same guinea that I know to be good, and of the same weight; and tliis will instantly show the diff"erence ; for the true ponderous metal wiU sink, and the false bulky one will be sustained in proportion to the greatness of its surface. Those whose busi- ness it is to examine the purity of metals, have a balance made for this purpose, by which they can precisely determine which is most ponderous, or, as it is expressed, which has the greatest specific gravity. Seventy-one pound and a half of quicksilver, is found to be equal in bulk to a hundred pound weight of gold. In the same proportion sixty of lead, fifty-four of silver, forty- eeven of copper, forty-five of brass, forty two of iron, and thirty- liflE EARTH. 1^5 nine of tin, are each equal to a hundred pound of the same most ponderous of all metals. This method of precisely determining the purity of gold, by weighing in water, was first discovered by Archimedes, to whom mankind have been indebted for many useful discoveries. Hiero, king of Sicily, having sent a certain quantity of gold to be made into a crown, the workman, it seems, kept a part for his own use, and supplied the deficiency with a baser metal. His fraud was suspected by the king, but could not be detected till he applied to Archimedes, who weighed the crown in water; and by this method, informed the king of the quantity of gold which was taken away. It has been said, that all fluids endeavour to preserve their level ; and, likewise, that a body pressing on the surface, tended to destroy that level. From hence, therefore, it will easily be inferred, that the deeper any body sinks, the greater will be the resistance of the depressed fluid beneath. It will be asked, therefore, as the resistance increases in proportion as the body descends, how comes the body after it has got a certain way, to sink at all ? The answer is obvious : From the fluid above pressing it down with almost as great a force as the fluid beneath presses it up. Take away, by any art, the pressure of the fluid from above, and let only the resistance of the fluid from below be suffered to act, and after the body is gone dowTi very deep, the resistance will be insuperable. To give an instance : A small hole opens in the bottom of a ship at sea, forty feet, we will suppose, below the surface of the water ; through this the water bursts up with great violence ; 1 attempt to stop it with my hand, but it pushes the hand violently away. Here the hand is, in fact, a body attempting to sink upon water, at a depth of forty feet, with the pressure from above taken away. The water, therefore, will overcome my strength ; and will continue to burst in till it has got to its level . if I should then dive into the hold, and clap my hand upon the opening, as before, I should perceive no force acting against my hand at all ; for the water above presses the hand as much down against the hole, as the water without presses it upward. For this reason, also, when we dive to the bottom of the water, we sustain a very great pres- sure from above, it is true, but it is counteracted by the press .la m2 13G HISTORY OF from beJow ; and the whole acting uniformly on the surface of the body, wraps us close round without injury. As I have deviated thus far, I will just mention one or two properties more, which water, and all such like fluids, is found to possess. And, first, their ascending in vessels which are emptied of air, as in our common pumps for instance. The air, however, being the agent-in this case, we must previously ex- amine its properties, before we undertake the explanation. The other property to be mentioned is, that of their ascending in small capillary tubes. This is one of the most extraordinary and inscrutable appearances in nature. Glass tubes may be drawn, by means of a lamp, as fine as a hair ; still preserving their hol- low within. If one of these be planted in a vessel of vi-ater, or spirit of wine, the liquor will immediately be seen to ascend; and it will rise higher, in proportion as the tube is smaller ; a foot, two feet, and more. How does this come to pass ? Is the air the cause ? No : the liquor rises, although the air be taken away. Is attraction the cause ? No : for quicksilver does not ascend, which it otherwise would. Many have been the theories of experimental philosophers to explain this pro- perty. Such as are fond of travelling in the regions of con- jectm'e, may consult Hawksbee, Morgan, Juiin, or Watson, who have examined the subject with great minuteness. Hithertoj however, nothing but doubts, instead of knowledge, have been the result of their inquiries. It will not, therefore, become U8 to enter into the minuteness of the inquiry, when we have so many greater wonders to call our attention away. ' 1 This phenompnon, which has so long^ embarrassed philosophers, is easily soluble upon the principle, that the attraction between the particles of glass and water is greater than the attraction between the particles of water them- selves : for, if a glass tube be held parallel to the horizon, and a drop of water be applied to the under side of the tube, it will adhere to it : nor will it fall from the glass, till its bulk and gravity are so far increased as to over, balance the attraction of the glass. Hence it is ea^y to conceive, how sensi- bly such a power must act ou the surface of a fluid not viscid, as water, contained within tlie cavity of a small glass tube ; as also that the quantity of the fluid raised, will be as the surface of tlie bore wU;ch it fills, that is, as tho diameter of the tube. THE EAaiH- ''^' CHAP. XIV. OF THE ORIGIN OF RIVERS. " The sun ariseth, and the sun goeth down, and pants for the place from whence he arose. All things are filled with labour, and man cannot utter it. All rivers run into the sea, yet the sea is not full. Unto the place whence the rivers come, thither they return again. The eye is not satisfied with seeing, nor the ear with hearing.'" Thus speaks the wisest of the Jews. And at 60 early a period was the curiosity of man employed in observing these great circulations of nature. Every eye attempted to ex- plain those appearances ; and every philosopher who has long thougut upon the subject, seems to give a peculiar solution. The inquiry whence rivers are produced ; whence they derive those unceasing stores of water, which continually enrich the world with fertility and verdure ; has been variously considered, and divided the opinions of mankind more than any other topic in natural history. In this contest the various champions may be classed under two leaders ; Mr De la Hire, who contends that rivers must be supplied from the sea, strained through the pores of the earth ; and Dr Halley, who has endeavoured to demonstrate that the clouds alone are sufficient for the supply. Both sides have brought in mathematics to their aid ; and have shown that long and laborious calculations can at any time be made to obscuie both sides of a question. De la Hire' begins his proofs, that rain-water, evaporated from the sea, is iuLufficient for the production of rivers : by show- ing that rain never penetrates the surface of the ear*;h above six- teen inches. From thence he infers, that it is impossible for it in many cases, to sink so as to be found at such considerable depths below. Rain-water, he grants, is often seen to mix with rivers, and to swell their currents ; but a much greater part of ir evaporates. " In fact," continues he, " if we suppose the earth eveiy where covered with water, evaporation alone would be sufficient to carry off two feet nine inches of it in a year ; and 8 Kcclesiastes, chap. i. ver. 5. 7, 8 3 Hiot. dc 1' Acad. 1713, r>. 56 M .3 138 HISTORY OF yet we very well know, that scarcely '^lineteen inches of rain-water falls in that time: ^o that evaporation would carry off a mueii greater quantity than is ever known to descend. The small quantity of rain-water that falls is, therefore, but barely suffi- cient for the purposes of vegetation. Two leaves of a fig-tree have been found, by experiment, to imbibe from the earth, in tire hours and a half, two ounces of water. This implies the great quantity of fluid that must be exhausted in the maintenance of one single plant. Add to this, that the waters of the river Run- gis will, by calculation, rise to fifty inches ; and the whole coun- try from whence they are supplied newr receives fifty inches in the year by rain. Besides this, there are many salt springs, which are known to proceed immediately from the sea, and are subject to its flux and reflux. In short, wherever we dig beneath the surface of the earth, except in a very few instances, water is to be found ; and it is by this subterraneous water that springs and rivers, nay, a great part of vegetation itself, is supported. It is this subterraneous water which is raised into steam, by the internal heat of the earth; that feeds plants. It is this subter- raneous water that distils through interstices ; and there, cooling, forms fountains. It is this that, by the addition of rains, is in- creased into rivers, and pours plenty over the whole earth.'* On the other side of the question', it is asserted, that the vapours which are exhaled from the sea, and driven by the winds upoti land, are more than sufiicient to supply not only plants with moisture, but also to furnish a sufficiency of water to the greatest rivers. P'or this purpose, an estimate has been made of the quantity of water emptied at the mouths of the greatest rivers ; and of the quantity also raised from the sea by evapora- tion ; and it has been found, that the latter by far exceeds th former. This calculation was made by Mr Marriotte. By him it was found, upon receiving such rain as fell in a year, in a pro- per vessel fitted for that purpose ; that one year with another, there might fall about twenty inches of water upon the surface of the earth, throughout Europe. It was also computed that the river Seine, from its source to the city of Paris, might cover an extent of ground, that would supply it annually with above eeven millions of cubic feet of this water, formed by evaporation. 1 Phil. Trans, vol. ii. p. ViS. THE EAllTII. 139 But upon computing the quantity which passed through the arches of one of its bridges in a yesu", it was found to amount only to two hundred and eighty millions of cubic feet, which is not above the sixth part of the former number. Kence it ap- pears, that this river may receive a supply, brought to it by the evaporated waters of the sea, by its current; and, therefore, evaporation is more than sufficient for maintaining the greatest rivers, and supplying the purposes also of vegetation.* • Tlie property which water has of evaporating spontaneously at all tem peratures, is one of the most important in the whole economy of nature. Foi upon it the growth of plants, aid the existence of living creatures upon the oarth, depends. The vapours thus continually rising, not merely from the surface of the sea, lakes, and rivers, but also from the dry land, are again Condensed, and fall in the state of rain or dew. The rain penetrates into the earth, and makes its way out again in springs. These Collecting together con. stitute rivers, wliich making their way to the sea, afford the means of living and enjoyment to numerous tribes and languages which occupy their banks. Let us suppose for a moment that this spontaneous evaporation were to rease, and let us contemplate the consequences. No more rain or dew could fall, the springs would cease to flow, the rivers would be dried up ; the whole water in the globe would be accumulated in the ocean ; the earth would be- come dry and parched; vegetables being deprived of moisture, could no longer continue to grow ; the cattle and beasts of every kind would ladt their usual food ; man himself would perish ; the earth would become a dull, inanimate, sterile mass, without any vegetables to embellish its surface, or any living creature to wander through its frightful deserts. If the atmosphere contained no vapour whatever, the annual evaporation from the surface of water could easily be determined, provided we were ac- quainted with the mean temperature of the place. But as the atmosphere is never free from vapour, we must either determine the mean quantity pre- sent by trial, or determine the actual evaporation by experiment. Now as far as evaporation is concerned, the surface of the globe presents three prin- i-ipal varieties ; namely, water, ground covered with grass or other vegetables, and bare soil. Dr Dobson made j. set of experiments during the years 1772, 1773, 177 1 and 1775, to determine the evaporation from the surface of water at IJver- pool during these years. He took a cylindrical vessel of twelve inches dia- meter, and having nearly filled it with water, exposed it beside a rain gau?e r.f the same aperture, and by adding water, or removing it occasionally, he Kept the surface at nearly the same height. By carefully registering the •.uantities added or taken away, and comparing them with the rain that fell, the amount of evaporation was ascertained. The mean annual evaporation from the surface of water at Liverpool amounted to 36.37 inches. The mean annual fall of rain at Liverpool, as ascertained by Dr Dobson, is (without reckoning the dew) 37.48 inches. We see at once firom this that more raia falls at Liverpool than can be accounted for by the evaporation. Consequent, by there must be a supply of vapour from the sea, and jirobably from the ivarmcr regions of the globe. no HISTOHY OF 111 this manner, the sea supplies sufficient humidity to the air, for furnishing tlie earth with all necessary moisture- One j)ar£ of its vapours falls upon its own bosom, before it airives upon land. Another part is arrested' by the sides of mountains, and is compelled, by the rising stream of air, to mount upward towards the summits. Here it is presently precipitated, dripping down by the crannies of the stone. In some places, entering into the caverns of the mountain, it gathers in those receptacles, which being once filled, all the rest overflows ; and breaking out by the sides of the hills, forms single springs. Many of these run down by the valleys or guts between the ridges of the mountain, and, coming to unite, forin little rivulets or brooks ; many of these meeting in one common valley, and gaining the plain ground, being grown less rapid, become a river ; A set of experiments upon the evaporation from ground covered with vegetables, aud from bare soil, was made by Mr Thomas Hoyle and Mr Ual- toii, at Manchester, during the years 1796, 1797, 1793. They got a cyliodri- cal vessel of tinned iron, ten inches in diameter, and three feet deep. There were inserted into it two pipes turned downwards for the water to run off from it into bottU's. One of these pipes was near the bottom of the vessel, the other was an inch from the top. This vessel was filled up for a few inches with gravel and sand, and all the rest of it with good fresh soil. It was then put into a hole in the ground, and the space around filled up with earth, except on one side for the convenience of putting bottles to the two pipes. Water was poured on to sadden the earth, and as much as would was suffered to run through without notice, by which the earth might be consi. dered saturated as with water. For some weeks the soil was constantly above the level of the upper pipe, but latterly it was always a little below it ; which made it impossible for any water to run through the upper pipe. For the first year the soil at top was bare, but during the last two years it was covered with grass the same as a green field. Things being thus circum. vtanced, a regular register was kept of the quantity of rain water that ran off from the surface of the earth by the upper pipe (while that took place,) and also of the quantity which sunk down through the three feet of eartli, and ran out through the lower pipe. A rain guage of the same diameter was kept close by to find the quantity of rain for any corresponding time. By this apparatus the quantity evaporated from the earth in the vessel during three years was ascertained. The annual evaporation was 25.1.58 inches. Now if to the rain we add five inches for dew (not reckoned in Mr Dalton's observations), it tollows that the mean annual evaporation from earth at Manchester, amounts to thirty inches. It follows likewise, from these ob- servations of Dalton and Hoyle, that there is but little difference between the evaporation o! green soil and bare soil. For the evaporation during the firs! year, when the soil in the vessel was bare, differed but little from that of th* two I'jilowing years when i^vas covered Vi'ith grass. THE EARTH. 141 and many of these uniting, make such vast bodies of water as the Rhine, the Rhone, and the Danube. There is still a third part which falls upon the lower grounds, and furnishes plants with their wonted supply. But the cir- culation does not rest even here ; for it is again exhaled into va- pour by the action of the sun ; and afterwards returned to that great mass of waters whence it first arose. " This," adds Dr Halley, " seems the most reasonable hypothesis ; and much more likely to be true, than that of those who derive all springs from the filtering of the sea-waters, through certain imaginary tubes or passa-ges within the earth ; since it is well known that the greatest rivers have their most copious fountains the most re- mote from the sea.'" This seems the most general opinion ; and yet, after all, it is stUl pressed with great difficulties ; and there is still room to look out for a better theory. The perpetuity of many springs, which always yield the same quantity, when the least rain or va- pour is afforded, as well as when the greatest, is a strong objec- tion. Derham^ mentions a spring at Upminster, which he could never perceive by his eye to be diminished, in the greatest droughts, even when all the ponds in the country, as well as an adjoining brook, have been dry for several months together. In the rainy seasons, also, it was never overflowed ; except some- times, perhaps, for an hour or so, upon the immission of the ex- ternal rains. He, therefore, justly enough concludes, that had this spring its origin from rain or vapour, there would be found an increase or decrease of its water, corresponding to the causes of its production. Thus the reader, after having been tossed from one h}'j)othe- sis to another, must at last be content to settle in conscioue ignorance. All that has- been written upon this subject, affords him rather something to say. than somettiing to think ; something rather for others than for himself. Varenius, indeed, although he is at a loss for the origin of rivers, is by no means so as to their formation. He is pretty positive that all rivers are artificial. He boldly asserts that their channels have been originally formed by the industry of nian. His reasons are, that when a new spring breaks forth, the water does not J Pliil. Trans. v.;l. ii. p. 128. 2 DirihamPIiysico-Theol, )4 2 HISTviRY OF irmke itself a new channel, but spreads over the adjacent land " Tlius," says he, " men are obliged to direct its course ; or, otherwise. Nature would never have found one." He enume. rates many rivers that are certainly known, from history, to have been dug by men. He alleges, that no salt-water rivers are found, because men did not want salt-water ; and as for salt, that was procurable at less expense than digging a river for it. However, it costs a speculative man but a small expense ot thinking to form such an hypothesis. It may perhaps engrosg the reader's patience to detain him longer upon it. Nevertheless, though Philosophy be thus ignorant as to the production of rivers, yet the laws of their motion, and the na- ture of their currents, have been very well explained. The Italians have particularly distinguished themselves in this res- pect ; and it is chiefly to them that we are indebted for the improvement. ' All rivers have their source either in mountains, or elevated lakes ;* and it is in their descent from these that they acquire 1 S. Guglit'lmini della Natura de Fiumi, passim. • Extensive accumulations of water, surrounded on all sides by the land, and having no direct communication with the ocean, or with any sea, are called lakes. Lakes are of four distinct kinds. The first class comprehends those which have no issue, and which do not receive any running water. These pools'are generally very small, and do not merit much attention. Some of these, as the Arendt, in Vieille Marche, are formed by the sinking down of the circumjacent lands : otliers, like the lake Albano, near Rome, appear to be old craters of volcanoes filled with water. The second class consists of those lakes which have an outlet, but whicli do not receive any running water. Such a lake is formed by a spring, or rather by a multitude of springs, which, placed on a lower level in a kind of reservoir, are obliged to fill thai before they find an outlet for their own waters. These lakes are neverthe. less fed by little streams of water, almost invisible, which descend from the surrounding lands, or from subterraneous canals. Some great rivers have lakes of this kind for their source. These lakes are naturally situated on great elevations ; there is one of this kind on Mount Rolando, in Corsica, which is l)29i feet above the level of the sea. The third class of lakes is very numerous, consisting of all such as receive and discharge streams of water. Each of the lakes of this class may be looked upon as forming a basin for receiving the neighbouring waters ; they have in general only one opening, which almost always takes its name from the principal river which flows into it. But it cannot, in strict propriety, be said that thnse rivers traverse the lakes, as their waters mingle with those of the basin over which they are diffusi'd. These lakes have often sources of their own, either near the bor- ders, or in their bottom. There are four or five lakes of this class in North America, which, in point of extent, resemble seas, and which, notwitlisland. THE EARIH. 14,3 that velocity which maintains their future current. At first thek course is generally rapid and headlong ; but it is retarded in its journey, by the continual friction against its banks, by the many obstacles it meets to divert its stream, and by the plains generally becoming more level as it approaches towards the sea. ing-, by the flow of a continual stream of fresh river.water, preserve their clearness and sweetness. The fourth class of lakes present phenomena much more difficult to explain. We mean those lakes which receive streams of water, and often great rivers, without having- any visible outlet The most celebrated of these is the Caspian Sea; Asia contains a great many others besides. The Niger, if it does not touch the sea, most probably falls into a lake of this kind, and not into a marsh. South America contains the lake Titicaca, which has no efflux, althougli it receives another very consider, able one into it. In short, these lakes appear to belong to the interior of great continents ; they are placed on elevated plains, which have no sensible declivity towards the sea, and which do not permit these collections of water to open for themselves a passage through which they may flow out. But why do these lakes, which are always receiving supplies of water, but have no outlet, why do they not overflow their lianks ? We may answer, that with respect to tliose which are situated in a hot climate, evaporation, as Halley observes, is sufficient to carry off their excess of water. It remains to be determined, whether the reasonings of this philosopher can with just- ness be applied to a climate so cold for example as that of the Caspian Sea Let us, in the first place, observe, that the quantity of water which the rivers pour into this basin, has been exaggerated : there are no other great rivers except the Wolga, the laik, and the Kur, which flow into it; the remainder consists only of .small rivulets. We must add, that the whole of the eastern iviast scarcely furnishes one rivulet to this extraordinary sea. And let us al.to remark, (for in physical geography every fact is worthy of attention,) that the Wolga, by no means a deep river, seems to be in part absorbed by the ground which borders its course ; and it is this humidity which renders these lands so distinguished for their fertility, when compared with the neighbouring soil. Finally, were we determined to suppose th.it there is a dUproportion between the extent of the Caspian .Sea and its evaporation, on the one side, and the volume of water that it receives on the other, (which we are far from blowing,) we have still to take into account the absorption of its waters by the calcareous mountains whicli border it towards the south and south west We know how porous and -spongy land of this kind is. Ail accounts agree in describing the mountains to the south of the Caspian a i being still more penetrated with moisture, and more abounding in springs than those of Mingrelia, which proves either absorpticm, or (what is ot more consequence,) a very strong evaporation. The insalubrity of the air near tiiese lakes, is another circumstance which still farther confirms the opinion of Halley. The physical phenomena which certain lakes present, have always excited the astonishment of the multitude. The periodical lakes are the most common. Those which are formed by excessive rains, and which are again dried up by the rays of the sun, by eva- poration, or infiltration, appear to be scarcely worthy of our attention. In Kurope these are nothing but pools, but between the tropics, these pools 144. HISTORY OF If this acquired velocity be quite spent, and the plain througb which the river passes is entirely level ; it will, notwithstanding, still continue to run from the perpendicular pressure of the wa- ter, which is always in exact proportion to the depth. Tliis perpendicular pressure is nothing more than the weight of the upper waters pressing the lower out of their places ; and conse- quently driving them forward as they cannot recede against the stream. As this pressure is greatest in the deepest parts of the river, so we generally find the middle of the stream most rapid •, both because it has the greatest motion thus communicated by the pressure and the fewest obstructions from the banks on either side.* sometimes cover spaces of several hundred leagues in length and breadth. Such are tlie famous lakes of Xarayes and Paria, inscribed on maps of America, and expunged from them by turns; it is probable that Africa con- tains a great many of this description. If there exist now in the numerous cavities of the earth subterraneous lakes of this kind, and if these communi. cate with other lakes which are visible, it is easy to imagine that the waters of these last may sometimes entirely disappear, by sinking down into the basin of the subterraneous lakes in proportion as thoy dry up. This lower basin again filling itself anew, the waters issue from it to till the superinr basin. If, in a supposable series of subterraneous cavities, the last link of tiie chain happen to be a mass of subterraneous water, situated at an elevated level in the bosom of a mountain, the periodical return of the waters in the visible basin may be accompanied by a motion similar to that of the spouting fountains. It is by means of such hydraulic machinery that nature keeps up the wonders of the lake of Cirknitz in Illyria, and in many others of the same description. The variations and motions of lakes, which do not depend upon an augmen. tation of quantity, present very complicated questions : That any lakes com- municate under ground « ith the sea, and owe their regular tides to such communication is much to be doubted. The equilibrium of the atmosphere, deranged by electricity, or by any other cause, may occasion water to rise up, by altering the pressure which retains it at its level. There is a bay in lake Huron where electric clouds continually remain, and no traveller has ever passed it without hearing thunder. In Portugal there is a priol near Beja. in Alentejo, which, by its loud rtnise, ind'cates the approach of a etorm. Other lakes appear agitated by the disengagement of subterraneous gases, or by winds which blow in some cavern with which the lake communicates. Near Boleslaw, in Bohemia, a lake of unfathomable depth sometimes in win- ter emits blasts of wind sufficiently strong to raise up in the air pieces of ice several quintals in weight. Two considerable lakes, Loch Loinond in Scotland, and the Welter in Sweden, often experience during the serenest weather vio- lent agitations. In the Murche of Brandebaurg, the pool of Krestin often commences in fine weather to boil up in whirlpools so as to engulph the little boats of the fishermen. Perhaps the decomposition of calcareous stones has an influence upon some of these phenomena. * Many great rivers in factttow with an almost imperceptible declivity. ITie THE EAKTH. ilj Rivers thus set into motion are almost always found to mako dicir own beds. Wliere they tind the bed elevated, they wear ils substance away, and deposit the stdinient ia the next hollow, so as 'in time to make the bottom of their channels even. Oa the other hand, the water is contimuilly gnawing and eating away the banks on each side ; and this with more force as the current hap- pens to strike more directly against them. By these means it al- ways has a tendency to render them more straight and parallel to its own course. Thus it continues to rectify its banks and enlarge Its bed ; and, consequently, to dimiiiish the force of its stream, till there becomes an equilibrium between the iurce of the water, a. id the resistance of its banks, upon which both will remain with- out any further mutation. And it is happy for man tiiat bounds are.thus put to the erosion of the earth by water ; and that we had all rivers only dig and widen themselves but lo a certain de^'ree."' Fn those plains ^ and large valleys where great rivers How, ll.c nviT of the Amazons has only ten ftet and a half of di-clivity upoii tw.i huu- oreJ leag^ue.-i of extent of watf r, which makes -^j of an iiii'h for every JOl.0 feet. The Seine, between Valvins and Serves, bus only one ioot declivity out of ikjOi). Xiie I^uire has, b.t veen Pouilly and Briare, one foot iu 7500 ;• but between Briare, and Orleans only one foot in 13,596. lu East i'lizi-land, in the United Provinces, two small neighbouring rivers liave, the one ^ of a.i iiicii, the other ^ of declivity for evi-ry 1000 feet. The M,-.rwedo, between Herdinxveld aud Dort, falls an iniii along- 1,125 f- posed to supply most of that great quantity of drift wood wliicb is seen floating in the seas neai- the Arctic circle. The Oby, of five hundred leagues, running from the lake of Kila into the Northern Sea. The Amour, in Eastern Tartary, whose course is aljout five hundred and seventy-five leagues, from its source to its entrance into the sea of Kamtschatka. The Kiam, in China, five hundred and fifty leagues in length. The Ganges, one of the most noted rivers in the world, and about as long as the former.* It rises in the mountains which separate India • The Ganges pursues a ronr>e of 1350 miles. It is a smnoth.ruiming and DKVigable river, and is supposed to employ upon it 30,000 boatmen. About '220 miles from the sea (but .30") reckoning the windings of the rivers,) com. nience.s the liead of tlie Delta of the Ganges, whieJi is considerably more than t«'iee the area of the Nile. The inundation of the river is in the latter end o{ July, and overflows an extent of 100 miles in breadth eontiguous to the river. The inundations of the Ganges and the Nile differ in this particular (that is to say, the lands of Bengal and Egypt.) that the Nile owes its floods entirely to tlie rain water that falls in the mountains, near its source ; but the inunda. tions ill Bengal are as much occasioned by the rain that-falls there, as by th" waters of the Ganges; as a proof of it, tlie lands in s^enera! are overflowed to a considerable height long before the bed of the river is filled. The aver- age swell of the Ganges, in the rainy seasons, is about .31 feet, and its fc! 1 ibout four inches per mile ; and the river flows at the rate of about three miles in the hour, but in the rainy season the rate is increased to six miles in the hour. The average quantity of water discharged by the Ganges into the sea is 80,000 cubic feet per second : biit during the rainy season the quantity di.«charged amounts to 405.000 cubic feet. The Ganges varies its channel very much during its course tlirough Bengal, wearing away the banks on one side, while land is foniK^d on the other side. The Burrampooter, which lia-s its source from the opposite side of tlie same mountains (the mountains of T)iibet) timt give rise to the Ganges, first takes its course eastward, or di- rectly opposite to that of the Ganges, through the country of Thibet, where ii is named the Sanpoo, or Zanciu, which bears the snme interpretation aa the Gonga of Hindostan : namely, the River. The Burrampooter enters Bengal on tlie north-east, after which it makes a circuit round the western (.rtiintol tl.e Marrow mountiiins ; and then altering its course to south it meeta THE EARTH. ],:i from Tartaiyj and running through the domiiiioiis of the Great Mogul, dis(;harges itself by several mouths into the bay of Ben- gal. It is not only esteemed by the Indians for the depth and pureness of its stream, but for a supposed sanctity which they believe to be in its waters. It is visited annually by several hundred thousand pilgrims, who pay their devotions to the river as to a god : for savage simplicity is always known to mistake the blessings of the Deity, for the Deity himself. They carrj their dying friends from distant countries, to expire on its banks; and to be buried in its stream. The water is lowest in April or JMay ; but the rains beginning to fall soon after, the flat coim- try is overflowed for several miles, till about the end of Sep- tember ; the waters then begin to retire, leaving a prolific sedi- raeni behind, that enriches the soil, and, in a few days' time, gives a luxuriance to vegetation, beyond what can be conceived by a European. Next to this may be reckoned the still more celebrated river Euphrates. This rises from two sources, northward of the city Erzerum, in Turcomania, and unites about three days' journey below the same ; from whence, after per- forming a course of five hundred leagues, it falls into the gulf of Persia, fifty miles below the city of Bassora in Arabia. The river Indus is extended, from its source to its discharge into the Arabian Sea, four hundred leagues. The largest rivers of Africa are, the Senegal, which runs a course of not less than eleven hundred leagues, comprehending the Niger, which some have supposed to fall into it. However, later accounts seem to aflirm that the Niger is lost in the sands, about three hundred miles up from the western coasts of Af- rica.* Be this as it may, the Senegal is well known to be the Ganges, about 40 miles from the sea. It is larger than the Gauges, and diiriug the last 60 miles, before itforms a junction with that river, its width is regularly from four to five miles, and, but for its freshness, might pass for an arm of the sea. Major Rennel was the original discoverer that the San- poo, of Thibet, is the same with the Burrarapooter. Before that time the SanpiM) had been supposed to discharge into the sea by the Gulf of Ava. * Many attempts have been made to determine the course of the Niger both by geographers and travellers in ancient as well as modern times ; but we are yet involved in the darkness of conflicting theories and ccutradictory reports. The very direction of this river was for a long period a debateable question. The Arabs of the middle ages attributed to the Niger a westward course to ' the Sea of DarkoefS,' or the Atlantic. They also conceived iha* the Niger and the Nilesprnngfrora the same origin. Leo -Africanus, however acknowledges tliat 152 HISTORV OF piavigiible for more than three hundred leagues up the country; ;!iid how much higher it may reach is not yet discovered, as the dreadful fatality of the inland parts of Africa, nut only deter* curiosity, but even avarice, which is a much stronger passion. At the end of last war, of fifty Englishmen that were sent to the factory at Galam, a place taken from the French, and nine hundred miles up the river, only one returned to tell the fate of his companions, who were destroyed by the climate. The cele- brated river Nile is said to he nine hundred and seventy leagues, from its source among the Mountains of the Moon, in Upper -Ethiopia, to its opening into the Mediterranean Sea.* The Bome geographers had made the Niger run from W. to E.,aDd teriniii.ite in a great lake. This was in fact the opinion of Herodotus 2000 years before ; and in this opinion Piolemy had coincided. '1 he Portuguese, on seeing the Senegal, the Gambia, and other great rivers proceeding from the unknown interior of y\fri(a, discharge themselves into the Atlantic, conceived that these rivern mi-ht be the mouths of the Niger itself, and therefore gave it a westward course. It was reserved for Mungo Park, to decide Ihe question as to the direction of the Nij,'er in favour of the old Grecian geograplier : on the 21st of July, 1796, that intrepid traveller beheld, from the heights of Sego, " the majestic Niyer flowing slowly from VV. to E." Equally as unsettled were the early notions as to the source of this river : for whilst some believed it to originate in the mountains of Mauritania, others affirmed that it issued from a lake to tlie S. of Bornou ; and others, as we have hinted, identified its fouiitain-head with that of the Nile. It is now decided from observation that the great central river of Africa, has Its source near Mount Lamba, in the country of the Soulimas, on the northern declivities of the Kong mountains, between G" and 10*' W. of Greenwich, and, according to Major Laing, at an elevation of 163S feet above the level of the Atlantic. It runs first N. E. through an unexplored country; and then, inclining a little more towards the E., passes the large cities of Baramakou, Yamima, Sego, and Sausaiiding. From the latter place it runs N. E., through lake Dibbie, to Timbuctoo, and thence sweeps in a circular direction to the S. of Houssa, where we are yet ignorant what becomes of it. The river is called, daring the know n part n) its course, Joliba by the native Africans. This name is a corruption of DhioH. ba : bu signifying ' a river,' in the Bambarra and Jlandingo languages, and dioli, or dhioli, pronounced jo/i or (IJoli, signifying ' red.' The Joliba, there- fore, means 'the Red river.' » The length of the Nile is about 2,000 miles ; but, as it receives few co.> lateral branches, and none from Ihe mouth of the Tacazze to the Delta — f. distance of nearly 1350 nautical miles — its breadth is seldom, if ever, moJe than one-third of a mile, and its average depth is only about 12 feet. This, however, must be understood as relating to its situation when confined v. ith. in its banks : during an inundation, it lays every level spot upon its banks under water. The ancients were not well acquainted with any other river w hich annually inundated the country around it This circumst-ince, there. Sv^eden, the river rushes do%vn from a prodigious high precipice, into a deep pit, with a terrible noise, and such dreadful iorce. that those trees designed for the masts of ships, which are float- ed down the river, are usually turned upside down in their lail, and often are shattered to pieces, by being dashed against the surface of the water in the pit •, this occurs if the masts fall side- ways upon the water ; but if they fall endways, they dive so fai under water, that they disai)pear for a quarter of an hour, or more ; the pit, into which they are thus plunged, has been often sounded with a line of some hundred fathoms long, but no ground has been found hitherto. There is also a cataract at Powers-court, in Ireland, in which, if I am rightly informed, the water falls three hundred feet perpendicular; which is a greater descent than that of any other cataract in any part of tha world. There is a cataract at Albany, in the province of New York, which pours its stream fifty feet perpendicular. But of all the cataracts in the world, that of Niagara, in Canada, if we consider the great body of water that falls, must be allowed to be the greatest, and the most astonishing. This amazing fall of water is made by the river St liawrence, in its passage from the lake Erie into the lake Ontario. We have already said that the St Lawrence was one of the largest rivers in the woi'ld ; and yet the whole of its waters are here poured down by a fall of a hundred and fifty feet perpendicular. It is not easy to bring the imagination to correspond with the greatness of the scene ; a river, extremely deep and rapid, and that serves to drain the waters of almost all North America into the Atlantic ocean, is here poured precipitately down a ledge of rocks, that rise, like a wall, across the whole bed of its stream. The width of the river, a little abo-'e, is near three quarters of a mile bro;id ; and the rocks, where it grows nar- rower, are four huiidied yards over. Their direction is not straight across, but hollowing inwards like a horse-shoe ; so that the cataract, which bends to the shape of the obstacle, rounding inwards, presents a kind of theatre the most tremendous in na- ture. Just in the middle of this circular wall of waters, a little island, that has braved the fury of the current, presents one ot its points, and divides the stream at top into two ; but it unites again long before it has got to the bottom. The noise of the la'l is heard at several leagues distance ; and the fury of the ©2 J GO HISTORY OF waters at the bottom of their fall is inconceivable. The dashing produces a mist that rises to the \ery clouds ; and that produces a most beautiful raiid)ow, when the sun shines. It may easily be conceived, that such a cataract quite destroys the navigation of the stream ; and yet some Indian canoes, as it is said, have been knowTi to venture down it with safety. Of those rivers that lose themselves in the sands, or are swal- lowed up by chasms in the earth, we have various information. What we are told by the ancients, of the river Alpheus, in Ar- cadia, that sinks into the ground, and rises again near Syracuse in Sicily, where it takes the name of Arethusa, is rather more known than credited. But we have better information with re- spect to tlie river Tigris being lost in this manner under mount Taurus ; of the Gundalquiver, in Spain, being buried in the sands ; of the river Greatah, in Yorkshire, running under ground, and rising again ; and even of the great Rhine itself, a part of which is no doubt lost in the sands, a little above Leyden. But it ought to be observed of this river, that by much the greatest pai-t arrives at the ocean ; for, although the ancient channel which fell into the sea, a little to the west of that city, be now entirely choked up, yet there are still a number of small canals, that carry a great body of water to the sea; and, besides, it has also two very large openings, the Lech and the Waal, be- low Rotterdam, by which it empties itself abundantly. Be this as it will, nothing is more common in sultry and sandy deserts, than rivers being thus either lost in the sands, or entirely dried up by the sun. And hence we sec, that under the line, the small rivers are but few ; for such little streams as are common in Europe, and which with us receive the name of rivers, would quickly evaporate, in those parching and extensive deserts. It is even confidently asserted, that the great river Niger is thus lost before it reaches the ocean ; and that its sup- posed mouths, the Gambia and the Senegal, are distinct rivers, that come a vast way from the interior parts of the countiy. It appears, therefore, that the rivers under the Line are large ; but it is otherwise at the Poles,' where they must necessarily be smalL In that desolate region, as the mountains are covered with perpetual ;"ce, which melts but little, or not at all, the 1 Craiit-z's History of Greenland, vol. i. p. U. THE KAUTIl. Ifil springs and rivulets are furnished with a very small supply. Here, therefore, men and beasts would perish, and die for thirst, if Providence had not ordered, that in the hardest winter, thaws should inter^'ene, which deposit a small quantity of snow-- water in pools under the ice ; and from this source the wretched inha- bitants drain a scanty beverage. Thus, whatever quarter of the globe we turn to, we shall iind new reasons to be satisfied with that part of it in which we re- side. Our rivers furnish all the plenty of the African stream, without its inundation ; they have all the coolness of the polar rivulet, with a more constant supply ; they may want the terri- ble magnificence of huge cataracts, or extensive lakes, but they are more navigable, and more transparent ; though less deep and rapid than the rivers of the torrid zone, they are more manage- ble, and only wait the will of man to take their direction. Ths rivers of the torrid zone, like the monarchs of the country, rule with despotic t}Tanny ; profuse in their bounties, and ungovern- able in their rage. The rivers of Europe, like their kings, are the friends, and not the oppressors, of the people ; bounded by known limits, abridged in the power of doing ill, directed by human sagacity, and only at freedom to distribute happiness and plenty. CHAP. XV. OF THE OCEAN IN GENERAL ; AND Of ITS SAI.TNESS. If we look upon a map of the world, we shall find that the ocean occupies considerably more of the globe, than the land is found to do. This immense body of waters is diffused round both the Old and New Continent, to the south ; and may sur- round them also to the north, for what we know, but the ice in those regions has stopped our inquiries. Although the ocean, iiroperly speaking, is but one extensive sheet of waters, conti- nued over every part of the globe, without interruption, and al- though no part of it is divided from the rest, yet geographers have distinguished it by different names ; as, the Atlantic or Western ocean, the Nurilcrn ocean, the Southern ocean, the IC}2 HISTORY OF Pacific ocean, and the Indian ocean. Others have divided it dif- fereiilly, and given ether names ; as the Frozen ocean, the Infe- rior ocean, or the American ocean. But all these being arbi- trary distinctions, and not of Nature's making, the naturalist may consider them \vi:h indifference. In this vast receptacle, almost all the rivers of the earth ulti- mately terminate ; nor do such great supplies seem to increase its stores ; for it is neither apparently swollen by their tribute, nor diminished by their failure ; it still continues the same. Indeed, what is the quantity of water of all the rivers and lakes in the world, compared to that contained in this great recep- tacle ?" If we should offer to make a rude estimate, we shall find that all the rivers in the world, flowing into the bed of the sea, with a continuance of their present stores, would take up at least eight hundred years to fill it to its present height. For, supposing the sea to be eighty-five millions of square miles in extent, and a quarter of a mile, upon an average, in depth, this, upon calculation, will give about twenty-one millions of cubic miles of water, as the contents of the whole ocean. Now, to estimate the quantity of water which all the ris'ers supply, take any one of them -, the Po, for instance, the quantity of whose discharge into the sea is known to be one cubic mile of water in twenty-six days. Now it will be found, upon a rude computa- tion, from the quantity of ground the Po, with its mfluent streams, covers, that all the rivers of the world furnish about two thousand times that quantity of water. In the space of a year, therefore, they will have discharged into the sea about twenty-six thousand cubic miles of water ; and not till eight hundred years will they have discharged as much water as is contained in the sea at present. I have not troubled the reader with the odd numbers, lest he should imagine I was giving pre- cision to a subject that is incapable of it. Thus great is the assemblage of waters diffused round our Iiabitable globe ; and yet, immeasurable as they seem, they are mostly rendered subservient to the necessities and the conve- niences of so little a being as man. Nevertheless, if it should be asked whether they be made for him alone, the question is not easily resolved. Some philosophers have perceived so much 1 I5ulTi>n, vol. i'. p. 70. THE EARTH .63 ana.ogy to man ii) t'lie formation of tlie ocean, ih-.A ilic",- liav<; not hesitated to assert its being made for him alone. The distribu- tion of land and water,- say they, is admirable ; the one be- ing laid against the other so skilfully, that there is a just equi- jioise of the whole globe. Thus the Northern ocean balances a rninst the Southern ; and the New Continent is an exact c'ounterwi.'ight to the Old. As to any objection from the ocean's occupying too large a share of the globe, they contend, that fhere could not have been a smaller surface employed to supply the earth with a due share of evaporation. On the other hand, some take the gloomy side of the question ; they either magnify^ its apparent defects ; or assert, that what seems defects to us, may be real beauties to some wiser order of beings.'' They ob- serve, that multitudes of animals are concealed in the ocean, and but a small part of them are known ; the rest, therefore, they fail not to say, were certainly made for their own benefit, and not for ours. How far either of these opinions be just, I will not presume to determine ; but of this we are certain, that God has endowed us v,ith abilities to turn this great extent of waters to our own advantage. He has made these things, perhaps, for other uses ; but be has given us faculties to convert them to our own. This much agitated question, therefore, seems to termi- nate here. We shall never know whether the things of this world have been made for our use ; but we very well know that we have been made to enjoy them. Let us then boldly affirm, that the earth, and all its wonders, are ours ; since we are fur- nished v.'ith powers to force them into our ser\ace. Man is the lord of all the sublunary creation ; the howling savage, the wind- ing serpent, with all the untameable and rebellious offspring of Nature are destroyed in the contest, or driven at a distance from his habitations. The extensive and tempestuous ocean, instead of limiting or dividing his power, only serves to assist his industry, and enlarge the sphere of his enjoyments. Its bil- lows and its monsters, instead of presenting a scene of terioi, only call up the courage of this little intrepid being; and the greatest danger that man now fears on the deep, is from his fel- low creatures. Indeed, when I consider the human race as 9 Derham's Physico-Tlicol. 3 Burnet's Theory, psa^ini. 4 Piipi-'s Ethic r.pistlcs, passim. iri-l IIISTORV OF Nature Ims formc'd llicm, there is but veiT little of tlie li!il)ilaWe globe that seems made for them. But when I consider them as accumulating the experience of ages, in commanding the earth, there is nothing so great or so terrible. What a poor contemptible being is the naked savage, standing on the beach of the ocean, and trembling at its tumults ! How little capable is he of converting its terrors into benefits ; or of saying, behold an element made wholly for my enjoyment ! He considers it as an angry deity, and pays it the homage of submission. But it is very different when he has exercised his mental powers ; when he has learned to find his own superiority, and to make it sub- servient to Ids commands. It is then that his dignity begins to appear, and that the true Deity is justly praised for having been mindful of man ; for having given him the earth for his habita- tion, and the sea for an inheritance. This power which man has obtained over the ocean, was at first enjoyed in common ; and none pretended to a right in that element where all seemed intruders. The sea, therefore, was open to all, till the time of the emperor Justinian. His succes- sor Leo granted such as were in possession of the shore, the sole right of fishing before their respective territories. The Thra- cian Bosphorus was the first that was thus appropriated j and from that time it has been the struggle of most of the powers of Europe to obtain an exclusive right in this element. The re- public of Venice claims the Adriatic. The Danes are in pos- session of the Baltic. But the English have a more extensive claim to the empire of all the seas encompassing the kingdoms of England, Scotland, and Ireland ; and although these have been long contested, yet they are now considered as their indisputable property. Every one knows that the great power of the nation is exerted on this clement ; and that the instant England ceases to be superior upon the ocean, its safety begins to be precarious. It is in some measure owing to our dependence upon the sea, and to our commerce there, that we are so well acquainted with its extent and figure. The bays, gulfs, currents, and shallows of the ocean, are much better known and examined than the pro\dnces and kingdoms ofthe earth itself. The hopes of ac quiring wealth by commerce, has carried man to much greatef length than the desire of gaining information could have done. In consequence of this, fhere is scarce a strait or a harbour. THE EARTH. I Ca Erarce a rock or a fjuirk sand, scarce an inflexion of the shore, or the jutting of a promontory, that has not been minutely describ- ed. But as these present very little entertainment to the ima- •rination, or delight to any but those whose pursuits are lucra- tive, they need not be dwelt upon here. While the merchant and the mariner are solicitous in describing currents and sound. ings, the naturalist is employed in observing wonders, though not so beneficial, yet to him of a much more important nature. The saltness of the sea seems to be foremost. Whence the sea has derived that peculiar bitterish saltness which we find in it, appears, by Aristotle, to have exercised the curiosity of naturalists in all ages. He supposed (and mankind were for ages content with the solution) that the sun continu- ally raised dry saline exhalations from the earth, and deposit- ed them upon the sea ; and hence, say his followers, the waters of the sea are more salt at top than at bottom. But, unfortunately for this opinion, neither of the facts is true. Sea-salt is not to be raised by the vapours of the sun ; and sea., water is not salter at the top than at the bottom. Father Bohours is of o])inion, that the Creator gave the waters of the ocean their saltness at the beginning : not only to prevent their cor- ruption, but to enable them to bear greater burthens. But their saltness does not prevent their comiption ; for stagnant sea- water, like fresh, soon grows putrid : and, as for their bearing greater burthens, fresh water answers all the purposes of naviga- tion quite as well. The established opinion, therefore, is that of Boyle,' who supposes, " That the sea's saltness is sup- j)iied not only from rocks or masses of salt at the bottom of the sea, but also from the salt which the rains, and rivers, and other waters, dissolve in their passage through many parts of the earth, and at length carry with them to the sea." But as there is a difference in the taste of rock-salt found at land, and that dissohed in the waters of the ocean, this may be produced by the plenty of nitrous and bituminous bodies that, with the salts, are likewise washed iiito that great receptacle. These .-ubstances being thus once carried to tbe sea, must for ever remain there ; for they do not rise by evaporation so as to be returned buck from whence they came. Nothing but the fresh 1 ni.ylp^vol. iii. p. --^ai. Ififi HISTORY or waters of the sea rise in vapours ; and all the saltness retnaih? behind. From hence it follows, that every year the sea must become more and more salt ; and this speculation Dr Halley carries so far as to lay down a method of finding out the age of the world by the saltness of its waters. " For if it be observed," says he, " what quantity of salt is at present contained in a certain weight of water taken up from the Caspian Sea, for example, and, after some centuries what greater quantity of salt is con- tained in the same weight of water, taken from the same place -, we may (conclude, that in proportion as the saltness has increased in a certain time, so much must it have increased before that time ; and we may thus by the rule of proportion make an esti- mate of the whole time wherein the water would acquire the de- gree of saltness it should be then possessed of.'" All this may be fine : however, an experiment, begun in this century, which is not to be completed till some centuries hence, is rather a little mortifying to modem curiosity ; and I am induced to think, the inhabitants round the Caspian Sea will not be apt to under- take the inquiry. This saltness is found to prevail in every part of the ocean ; and as much at %he surface as at the bottom. It is also found in all those seas that communicate with the ocean •, but rather in a less degree. The great lakes, likewise, that have no outlets nor communi- cation with the ocean, are found to be salt •, but some of them in less proportion. On the contrary, all those lakes through which rivers run into the sea, however extensive they be, are, notwithstanding, very fresh : for the rivers do not deposite their salts in the bed of the lake, but carry them with their currents into the ocean. Thus the lakes Ontario and Erie, in North America, although for magnitude they may be considered as in- IrMid seas, are nevertheless fresh-water lakes ; and kej)t so by the river St Lawrence, which passes through them. But those lakes that have no communication with the sea, nor any rivers going out, although they be less than the former, are, however, always salt. Thus, that which goes by the name of the Dead Sea, though very small, when compared to those already mention- ed, is so exceedingly salt, that its waters seem scarcely capable 1 Pliii. Trans, vol. v. p. 2ia THE EAUTIU 167 of dissolving any more. The lakes of ilexico and of Titicaca in i'ei u, though of no great extent, are nevertheless salt j and both tor the same reason. Those who are willing to turn all things to the best, have not failed to consider this saltness of the sea as a jieculiar bless, ing from providence, in order to keep so great an element sweet and wholesome. What foundation there may be in the remark, I will not pretend to determine ; but we shall shortly find a much better cause for its being kept sweet, namely, its motion. On the other hand, there have been many who have consid- ered the subject in a different light, and have tried every endea- vour to make salt-water fresh, so as to supply the wants of ma- riners in long voyages, or when exhausted of their ordinarj^ stores. Aubrst itwas supposed simple distillation would do ; but it w as soon found, that the bitter part of the water still kept mixed. It was then tried by uniting salt of tartar with sea- water, and distilling both, but here the expense was greater than the advantage. Calcined bones were next thought of; but a hogshead of calcin- ed bones, carried to sea, would take up as much room as a hogs- head of water, and was more hard to be obtained. In this state, therefore, have the attempts to sweeten sea-water rested ; the chymist, satisfied with the reality of his invention, and the ma- riner convinced of its being useless. I cannot, therefore, avoid mentioning a kind of succedaneum which has been lately con- ceived to answer the purposes of fresh water, when mariners are quite exhausted. It is well known, that persons who go into a warm bath, come out several ounces heavier than they went in ; their bodies have imbibed a correspondent quantity of water. This more particularly happens, if they have been pre- viously debarred from drinking, or go in with a violent thirst ; which they quickly find quenched, and their spirits restored. It was supposed, that in case of a total failure of fresh water a* sea, a warm bath might be made of sea-water, for the use oi mariners ; and that their pores would thus imbibe the tluid without any of its salts, which would be seen to crystalize on the surface of their bodies. In this manner it is supposed, a sufii- dent quantity of moisture may be procured to sustain life, till lime or accident furnish a more copious sujjply. 1C8 HISTORY CF But however this be, the sultness of the seii au) by no means be considered as a principiil cause in pr«st'rviiig its waters from jiutrefaction. The ocean Vms its currents, like rivers which tir- culate its contents round the globe ; and these may be said to be the great agents that keep it sweet and wholesome. Its saltness alone would by no means answer this purpose : and some have even imagined that the various substances wiih which it is mixed, rather tend to promote putrescence than impede it. Sir Robert Hawkins, one of our most enlightened navigators, gives the fol- lowing account of a calm in which the sea, continuing for some time without motion, began to assume a very formidable appear, ance. " Were it not," says he, " for the moving of the sea, by the force of wi.'ids, tides, and currents, it would corrupt all the woit.d. The experiment of this I snw in the year 15f)0, lybig with a fleet about the islands of the Azores, almost six months ; the greatest part of which time we were becabned. Upon which -il] the sea became so replenished with several sorts of jellies, and of serpents, adders, and snakes, as seemed wonderful . some green, some black, some yellow, some white, some of divers colours ; and many of them had life ; and some there were a yard and a half, and two yards long: which had I not seen, I could hardly have believed. And hereof are witnesses all the company of the ships which were then present ; so that hardly a man could draw a bucket of water dear of some corruption. In which voyage tow.n-ds the end thereof, many of every shij) fell sick, and began to dit; apace. But the speedy passage into our countiy was a remt dy to the crazed, and a preservative for those that were not touched." This shows abundantly how little the sea's saltness was ca- pable of preserving it from putrefaction : but to put the li.atter beyond all doubt, Mr Boyle kept a quantity of sca-water, takeji up in the English Channel, for some time barrelled up ; and in the space of a few weeks it began to acquire a fetid smell.' He was also assured, by one of his acquaintance, who was becalmed lor twelve or fourteen days in the Indian Sea, that the water for want of motion, began to stink; and that had it continued much longer, the stench would probably have poisoned him. It is the motion, therefore, and not the saltness of the sea, that 1 Boyle, vol. iii. p. 222.\ THE KAIiTlI. 1G9 preserves it in its present state of salubrity ; and this very pro- Dably, by dashing and breaking in pieces the rudiments, if I may so call tbeni, of the various animals that would otherwise breed there, and putrefy. There are some advantages, however, whicn are derived from the saltness of the sea. Its waters being evaporated, furnish that salt which is used for domestic purposes ; and although in some - places It is made from springs, and in others dug out of mines, yet the greatest quantity is made only from the sea. That which is called hay salt, (from its coming to us by the Bay of Biscay,) is a stronger kind, made by evaporation in the sun ; that called common salt, is evaporated in pans over the fire, and is of a much inferior quality to the former. /.nother benefit arising from the quantity of salt dissolved in the sea is, that it thus becomes heavier, and consequently more buoyant. JMr Boyle, who examined the difference between sea- water and fresh, found that the former appeared to be about a forty-fifth part heavier than the latter. Those, also, who have had opportunities of bathing in the sea, pretend to have experi- enced a much greater ease in sw imming there than in fresh water. However, as we see they have only a forty-fifth part more of their weight sustained by it, I am apt to doubt whether so minute a difference can be practically perceivable. Be this as it may, as sea-water alters in its weight from fresh so it is found also to diffLT from itself in different parts of the ocean. In ge- neral, it is perceivable to be hea\aer, and consequently Salter, the nearer we approach the Line.' But there is an advantage arising from the saltness of the waters of the sei, much greater than what has been yet mention- ed; which is, that their congelation is thus retarded. Some indeed have gone so far as to say, that sea-water never freezes ;' but this is an assertion contradicted by experience. However it is certain, that it requires a much greater degree of cold to freeze it than fresh water ; so that while rivers and springs are- seen converted into one solid body of ice, the sea is always fit for navigation, and no way afiected by the coldness of the seve- rest wnter. It is, therefore, one of the greatest blessings wt derive from this element that, when at land all the stores of 2 Phil. Trans, vol. ii p. "2!'7. 3 Macrubiaa. 170 HISTORY OF nature are Jocked up from us, we find the sea ever opeii to out necessities, aud patient of the hand of industry. But it must not be supposed, because in our temperate climate we never see the sea frozen, that it is in the same manner open in every part of it. A very little acquaintance with the accounts of mariners, must have informed us, that at the polar regions it is embarrassed with mountains and moving sheets of ice, that often render it impassable. These tremendous floats are of dif- ferent magnitudes ; sometimes rising more than a thousand feet above the surface of the water ;' sometimes diffused into plains of above two hundred leagues in length ; and, in many parts, sixty or eighty broad. They are usually divided by fissures ; one piece following another so close, that a person may step from one to the other. Sometimes mountains are seen rising amidst these plains, and presenting the appearance of a variegat- ed landscape, with hills and valleys, houses, churches, and towers. These are appearances in which all naturalists are agreed ; but the great contest is respecting their formation. Mr Buffon asserts,^ that they are formed from fresh water alone, which con- gealing at the mouths of great rivers, accumulate those huge masses that disturb navigation. However, this great naturalist seems not to have been aware, that there are two sorts of ice floating in these seas ; the flat ice and the mountain ice .- the one formed of sea-water only ; the other of fresh.^ The flat, or driving ice, is entirely composed of sea-water ; which, upon dissolution, is found to be salt; and is readily dis- tinguished from the mountain, or fresh water jce, by its white- ness, and want of transparency. This ice is much more terrible to mariners than that which rises up in lumps : a ship can avoid the one, as it is seen at a distance ; but it often gets in among the other, which, sometimes closing, crushes it to pieces. This, which manifestly has a diff'erent origin from the fresh-water ice, may perhaps have been produced in the Icy Sea, beneath the pole; or along the coasts of Spitzbergen or Nova-Zembla. The mountain ice, as was said, is different in every respect, being formed of fresh water, and appearing hard and transparent , it is generally of a pale green colour, though some pieces are of a beautiful sky-blue ; many large masses also appear gray, and 1 Cnuitz's History of Grcenlnod, vol. i. p, 31. •2 Kiillcm, vol. ii. p. 91. 3 Crantz. TJIE EARTH. 171 some black. Jf examined more nearly, they are found to be in. corporated with earth, stones, and brush-wood, washed from the shore. On these also are sometimes found, not only earth, bui nests with birds' eggs, at several hundred miles from land. The generality of these, though almost totally fresh, have neverthe- less a thick crust of salt-water frozen upon them, probably from the power that ice has sometimes to produce ice. Such moun- tains as are here described, are most usually seen at spring-time, and after a violent storm, driving out to sea, where they at first terrify the mariner, and are soon after dashed to pieces by the continual washing of the waves; or driven into the warmer regions of the south, there to be melted away. They sometimes, however, strike back upon their native shores, where they seem to *^ake root at the feet of mountains ; and, as Martius tells us, are sometimes higher than the mountains themselves. Those seen by him were blue, full of clefts and cavities made by the rain, and crowned with snow, which alternately thawing and freezing every year, augmented their size. These, composed oi materials more solid than that driving at sea, presented a variety of agreeable figures to the eye, that with a little help from faticy assumed the appearance of trees in blossom ; the inside of churches, with arches, pillars, and windows ; and the blue-col- oured rays, darting from within, presented the resemblance ot a glory. If we inquire into the origin and formation of these, which. as we see, are very different from the former, I think we have a very satisfacton,' account of them in Crantz's History of Green- land ; and I will take leave to give the passage with a very few alterations. " These mount-ams of ice," says he, " are not salt, like the sea-water, but sweet ; and, therefore, can be formed no- where except on the mountains, in livers, in caverns, and against the hills near the sea -shore. The mountains of Greenland are 80 high that the snow which falls upon them, particidarly on the north. side, is in one night's time wholly converted irto ice : they also contain clefts and cavities, where the sun seldom or never injects his rays ; besides these, are projections, or landing places, on the decJi\-ities of the steepest hills, where the rain and snow. water lodge, and quickly congeal. When now tlie accumulated flakes of snow slide down, or fall with the rain from the emi- nences above on these prominences ; or, when here and there a V 2 1(^2 HISTORY OF mountain-spring comes rolling down to such a lodging-place, where the ice has already seated itself, they all freeze, and add their tribute to it. This, by degrees, waxes to a body of ice, that can no more be overpowered by the sun ; and which, thougb it may indeed, at certain seasons, diminish by a thaw, yet, upon the whole, through annual acquisitions, it assumes an annual growth. Such a body of ice is often prominent far over the rocks. It does not melt on the upper surface, but underneath ; and often cracks into many larger or smaller clefts, from whence the thawed water trickles out. By this it becomes at last so weak, that being overloaded with its own ponderous bulk, it breaks loose, and tumbles down the rocks with a terrible crash. Where it happens to overhang a precipice on the shore, it plunges into the deep with a shock like thunder ; and with such an agitation of the water, as will overset a boat at some distance, as many a poor Greenlander has fatally experienced." Thus are these amazing ice.mountains launched forth to sea, and found floating in the waters round both the poles. It is these that have hindered mariners from discovering the extensive countries that lie round the South Pole ; and that probably block up the j)assage to China by the North. I will conclude this chapter with one effect more, produced by the saltness of the sea ; which is the luminous appearance of its waves in the night. All who have been spectators of a sea by night, a little ruffled with winds, seldom fail of observing its fieiy brightness. In some places it shines as far as the eye can reach ;' at other times, only when the waves boom against the side of the vessel, or the oar dashes into the water. Some seas shine often ; others more seldom ; some, ever when particular winds blow ; and others, within a narrow compass ; a long tract of light being seen along the surface, whilst all the rest is hid in total darkness. It is not easy to account for these extraordinary appearances : some have supposed that a number of luminous insects produced the effect, and this is in reality sometimes the case ; in general, however, they have every resemblance to that light produced by electricity ; and, probably, arise from the agita- tion and dashing of the saline particles of the fluid against each other. But the marmer in which this is done, for we can pro- 1 boyle, vol. J. p. 2M. THE EARTH. IVS duce nothing similar by any exiieriments hitherto made, remains for some happier accident to discover. Our progress in the knowledge of nature is slow ; and it is a mortifying considera- tion, that we are hitherto more indebted for success to chance liian industry'. CHAP. XVI. OF THE TIDES MOTION, AND CURRENTS, OF THE SEA ; WITH THEIR EFFECTS. It was said in the former chapter, that the waters of the sea were kept sweet by their motion ; without which they would soon putrefy, and spread universal infection. If we look for final causes, here indeed we have a great and an obvious one that presents itself before us. Had the sea been made without motion, and resembling a pool of stagnant water, the noble races of animated nature would shortly be at an end. Nothing would then be left alive but swarms of ill-formed creatures, with scarcely more than vegetable life ; and subsisting by putrefaction. Were this extensive bed of waters entirely quiescent, millions of the smaller reptile kinds would there find a proper retreat to breed and multiply in ; they would find there no agitation, no concus- sion in the parts of the fluid to crush their feeble frames, or to force them from the places where they were bred : there they would multiply, if security and ease, enjoy a short life, and putrefying, thus again give nourishment to numberless others, as little worthy of existence as themselves. But the motion of this great element effectually destroys the number of these viler creatures ; its currents and its tides pro- duce continual agitations, the shock of which they are not able to endure ; the parts of the fluid rubbing against each other destroy all viscidities ; and the ocean, if I may so express it, acquires health by exercise. The most obvious motion of the sea, and the most generally acknowledged, is that of its tides. This element is observed to flow for certain hours, from the south towards the north ; in which motion or flux, which lasts about six hours, the soa gra- ^ ii 171- HISTOUY OF dually swells ; so that entering the mouths of rivers, it drives back the river- waters to their heads. After a continual flux of six hours, the sea seems to rest for a quarter of an hour ; and then begins to ebb, or retire back again, from north to south, for six hours more ; in which time the waters sinking, the rivers resume their natural course. After a seeming pause of a quarter of an hour, the sea again begins to flow as before : and thus it has alternately risen and fallen, twice a-day, since the creation. This amazing appearance did not fail to excite the curiosity, as it did the wonder of the ancients. After some wild conjec- tures of the earliest philosophers, it became well known in the time of Pliny, that the tides were entirely under the influence, in a small degree, of the sun ; but in a much greater of the moon. Jt was found that there was a flux and reflux of the sea, in the space of twelve hours fifty minutes, which is exactly the time of a lunar day. It was observed, that whenever the moon was in the meridian, or, in other words, as nearly as possible over any part of thd sea, that the sea flowed to that part, and made a tide there ; on the contrary, it was found, that when the moon left the meridian, the sea began to flow back again from whence i* came ; and there might be said to ebb. Thus far the waters of the sea seemed very regularly to attend the motions of the moon. But as it appeared, likewise, that when the moon was in the opposite meridian, as far off on the other side of the globe, that there was a tide on tliis side also ; so that the moon produced two tides, one by her greatest approach to us, and another by her greatest distance from us : in other words, the moon, in once going round the earth, produced two tides, always at the same time; one on the part of the globe directly under her ; and the other, on the part of the globe dii-ectly opposite. Mankind continued for several ages conterit with knowing the general cause of these wonders, hopeless of discovering the par- ticular manner of the moon's operation. Kepler was the first who conjectured that attraction was the principal cause ; assert, ing, that the sphere of the moon's operation extended to the earth, and drew up its waters. The precise manner in which this is done, was discovered by Newton. The moon has been found, like all the rest of the planets, to attract and to be attracted by the earth. This attraction pre- THE EARTH. 175 vails tlircughout our whole planetary system. The more mat- ter there is contained in any body, the more it attracts ; and its influence decreases in proportion as the distance, when squared, increases. This being premised, let us see what must ensue upon supposing the moon in the meridian of any tract of the sea. The surface of the water immediately under the moon, is nearer the moon than any other part of the globe is ; and, there- fore, must be more subject to its attraction, than the waters any where else. The waters will, therefore, be attracted by the moon, and rise in a heap ; whose eminence will be the highest where the attraction is greatest. In order to form this eminence, it is obvious that the surface, as well as the depths, wdW be agi- tated ; and that wherever the water runs from one part, suc- ceeding waters must run to fill up the space it has left. Thus the waters of the sea, running from all parts to attend the mo tion of the moon, produce the flowing of the tide ; and it is high tide at that part wherever the moon comes over it, or to its meridian. But when the moon travels onward, and ceases to point over the place where the waters were just risen, the cause here ot their rising ceasing to operate, they will flow back by their na- tural gravity into the lower parts from whence they had tra-- velled; and this retiring of the waters will form the ebbing ot the sea. Thus the first part of the demonstration is obvious ; since, in general, it requires no great sagacity to conceive that the waters nearest the moon are most attracted, or raised highest by the moon. But the other part of the demonstration, namely, how there come to be high tides at the same time, on the opposite side of the globe, and where the waters are farthest from the moon, is not so easy to conceive. To comprehend this, it must be observed, that the part of the earth and its waters that are farthest from the moon, are the parts of all others that are least attracted by the moon ; it must also be observed, that all the waters, when the moon is on the opposite side of the .earth, must be attracted by it in the same direction that the earth itself . attracts them ; that is, if I may so say, quite through the body of the earth, towards the moon itself. This, therefore, being conceived, it is plain that those waters which are farthest from the moon, will have less weight than those of any other part, on 176 HISTORY OF the same side of the globe ; because the moon's attraction, which conspires with the earth's attraction, is there least. Now, therefore, the waters farthest from the moon, having less weight, and being lightest, will be pressed on all sides, by those that, having more attraction, are heavier : they will be pressed, I say on all sides ; and the heavier Vi^aters flowing in, will make them swell and rise, in an eminence directly opposite to that on the other side of the globe, caused by the more immediate influence of the moon. In this manner the moon, in one diurnal revolution, produces two tides ; one raised immediately under the sphere of its in- fluence, and the other directly opposite to it. As the moon travels, this vast body of waters rears upward, as if to watch its motions; and pursues the same constant rotation. Howevei, in this great work of raising the tides, the sun has no small share; it produces its own tides constantly every day, just as the moon does, but in a much less degree, because the sun is at an immensely greater distance. Thus there are solar tides, and lunar tides. When the forces of these two great luminaries concur, which they always do when they are either in the same, or in opposite parts of the heavens, they jointly produce a much greater tide, than when they are so situated in the heavens, as each to make peculiar tides of their own. To express the very same thing technically ; in the conjunctions and oppositions of the sun and moon, the attraction of the sun conspires with the attraction of the moon ; by which means the high spring-tides are formed. But in the quadratures of the sun and moon, the wnter raised by the one is depressed by the other ; and hence thelowb. neap-tides have their production. In a word, the tides are greatest in the syzigies, and least in the quadratures. This theory well understood, and the astronomical terms pre iously known, it may readily be brought to explain the various appearances of the tides, if the earth were covered with a deen sea, and the waters uninfluenced by shoals, currents, straits, or tempests. But in every part of the sea, near the shores, the geographer must come in to correct the calculations of the as- tronomer. For, by reason of the shallowness of some places, and the narrowness of the straits in others, there arises a great diversity in the effect, not to be accounted for without an exact knnvledge of all the circumstances ol the place. In the great THE EARTH. 177 depths of the ocean, for instance, a very slow and imperceptible motion of the whole body of water will suffice to raise its sur- face several feet high ; but if the same increase of water is to be conveyed through a narrow channel, it must rush through it with the most impetuous rapidity. Thus, in the English Chan- nel, and the German Ocean, the tide is found to flow strongest in those places that are narrowest ; the same quantity of \rdter being, in this case, driven through a smaller passage. It is often seen, therefore, pouring through a strait with great force ; and, by its rapidity, considerably raised above the surface of that part of the ocean into which it runs. This shallowness and narrowness in many parts of the sea, give also rise to a peculiarity in the tides of some parts of the woiM. For in many places, and in our own seas in particular, the greatest swell of the tide is not while the moon is in iis meridian height, and directly over the place, but some time after it has declined from thence. The sea, in this case, being ob- structed, pursues the moon with what despatch it can, but does not arrive with all its waters till long after the moon has ceased to operate. Lastly, from the shallowness of the sea, and from its being obstructed by shoals and straits, we may account for the Mediterranean, the Baltic, and the Black Sea, having no sensible tides. These, though to us they seem very extensive, are not however large enough to be aifected by the influence of the moon ; and as to their communication with the ocean, through such narrow inlets, it is impossible, in a few hours' time, that they should receive and return water enough to raise or depress them in any considerable degree. In general, therefore, we may observe, that all tides are much higher, and more considerable, in the torrid zone, than in the rest of the ocean ; the sea in those parts being generally deeper, and less aifected by changeable winds, or winding shores.' The greatest tide we know of, is that at the mouth of the river Indus, where the water rises thirty feet in height How great, there, fore, must have been the amazement of Alexander's soldiers at 80 strange an appeararice ! They who always before had been accustomed only to the scarcely perceptible risings of the Medi- terranean, or the minute intumescense of the Black Sea, when 1 Bufi'on. vol. ii p. 187. 178 IWSTOIIV OF made at once spectators of a river rising and falling tliirfy feci ill a few hours, must, no doubt, have felt the most extreme awe and, as we are told,' a mixture of curiosity and apprehension. The tides are also remarkably high on the coasts of Mulay, in the straits of Sunda, in the Red Sea, at the mouth of the river St Lawrence, along the coasts of China and Japan, at Panama, and in the gulf of Bengal. The tides at Tonquin, however, are the most remarkable in the world. In this part there is but one tide, and one ebb, in twenty-four hours ; whereas, as we have said before, in other places there are two. Besides, there, twice in each month, there is no tide at all, when the moon is near the equinoctial, the water being for some time quite stag- nant. These, with some other odd appearances attending the same phenomena, were considered by many as inscrutable ; but Sir Isaac Newton, with peculiar sagacity, adjudged them to anse from the concurrence of two tides, one from the South Sea, and the other from the Indian Ocean. Of each of these tides there come successively two every day ; two at one time greater, and two at another that are less- The time between the ai-rival of the two greater, is considered by him as high tide ; the time between the two lesser, as ebb. In short, M'ith this clue, that great mathematician solved every appearance, and si established his theory as to silence every opposer. This fluctuation of the sea from the tides, produces another, and more constant rotation of its waters, from the east to the west, in this respect following the course of the moon. This may be considered as one great and general current of the waters of the sea ; and although it be not every where distinguishable it is nevertheless every where existent, except when opposed by some particular current or eddy, produced by partial and local causes. This tendency of the sea towards the west, is plainly perceivable in all the great straits of the ocean ; as, for instance, in those of Magellan, where the tide running in from the east, rises twenty feet high, and continues flowing six hours ; where- as the ebb continues but two hours, and the current is directed tu the west. This proves that the flux is not equal to th« reiiux ; and that from both results a motion of the sea west* I Quintus Curtius. TrtE EARTH 179 wnn], which is more powerful during the tune of the flux thati r!io retiux. But this motion westward has been sensibly observed by n;- vig;ators, in their passage back from India to Madagascar, and so on to Africa. In the great Pacific Ocean also it is very perceivable ; but the places where it is most obvious, are, as vvas said, in those straits which join one ocean to another. In t)ie straits between the Maldivia islands, in the gulf of Mexi- co, between Cuba and Jucatan. In the straits of the gulf of Paria, the motion is so violent, that it hath received the appel- lation of the Dragon's Mouth. Northward, in the sea of Canada, in Waigat's straits, in the straits of Java, and, in short, in every strait where the ocean on one part pours into the ocean on the other. In this manner, therefore, is the sea carried with an unceasing circulation round the globe ; and at the same time that its waters are pushed backward and forward with the tide, they have thus a progressive current to the west, which though less obser^'able, is not the less real. Beside these two general motions of the sea, there are others which are particular to many parts of it, and are called currents. These are found to run in all directions, east, west, north, and south ; being formed, as was said above, by various causes ; the prominence of the shores, the narrowness of the straits, the variations of the wind, and the inequalities at the bottom. These, though no great object to the philosopher, as their causes are generally local and obvious, are nevertheless of the most material consequence to the mariner ; and without a knowledge of which he could never succeed. It often has happened, that when a ship ha , unknowingly got into one of these, every thing seems to go forward with success, the mariners suppose them- selves every hour approaching their wished-for port, the wind fills their sails, and the ship's prow seems to divide the water ; but, at last, by miserable experience they find that, in.^tead of going forward, they have been all the time receding. The busi. ness of currents therefore, makes a considerable article in navi- gation ; and the direction of their stream, and their rapidity, hni* been carefully set down. This some do by the observation ot the surface of the current ; or by the driving of the troth along the sliore ; or by throwing oirt what is called the log-line, with a buoy made for that purpose, and by the direction and motion I THE EARTH. 181 previously marked it by a ring ot rron. Some time after a dol- phin was caught in the Red sea, and quickly known by the ring to be the same that had been taken in the Mediterranean be- fore. Such, however, as have not been willing to found their opinions upon a story, have attempted to account for the dispo- sal of the waters of the Mediterranean by evaporation. For this purpose they have entered into long calculations upon the extent of its surface, and the quantity of Mater that would be raised from such a surface in a year. They then compute how much water runs in by its rivers and straits in that time ; and find, that the quantity exhausted by evaporation, greatly exceeds the quantity supplied by rivers and seas. This solution, no doubt, would be satisfactory, did not the ocean, and the Eiixine, evaporate as well as the Mediterranean : and as these are sub- ject to the same drain, it must follow, that all the seas will in this respect be upon a par ; and, therefore, there must be some other cause for this unperceived drain, and continual supply. This seems to be satisfactorily enough accounted for by Dr Smith, who supposes an under current running through the straits of Gibraltar, to carry out as much water into the ocean, as the upper current continually carries in from it. To confirm this, he observes, that nearer home, between the North and the South Foreland, the tide is known to rini one way at top, and the ebb another way at bottom. This double current he also confirms by an experiment communicated to him by an able sea- man, who being with one of the king's frigates in the Baltic, found he went with his boat into the mid- stream, and was car- ried violently by the current ; upon which a basket was sunk, with a large cannon-ball, to a certain depth of water, which gave a check to the boat's motion : as the basket sunk still lower, the boat was driven, by the force of the water below, against the upper current ; and the lower the basket was let dowoi, the stronger the under current was found, and the quicker was the boat's motion against the upper stream, which seemed not to be above four fathom deep. From hence we may readily infer, that the same cause may operate at the straits of Gibraltar ; and that while the Mediterranean seems replenishing at top, it may be emptying at bottom. The number of the currents at sea are impossible to be recount- ed, nor mdeed are they always known ; new ones are daily pro- Q 182 HISTORY OF (Sliced by a variety of causes, and as quickly disappear. WLen a regular current, is opposed by another in a narrow strait, or where the bottom of the sea is very uneven, a whirlpool is often (ormed. These were formerly considered as the most formida- ble obstructions to navigation ; and the ancient poets and histo- -ians speak of them with terror ; they are described as swallow- ing up ships, and dashing them against the rocks at the bottom ; apprehension did not fail to add imaginary terrors to the descrip- tion, and placed at the centre of the whirlpool a dreadful den, fraught with monsters whose bowlings served to add new hor- rors to the dashings of the deep. Mankind at present, how- ever, view these eddies of the sea with very little apprehension ; and some have wondered how the ancients could have so much overcharged their descriptions. But all this is very naturally accounted for. In those times when navigation was in its infancy, and the slightest concussion of the waves generally sent the poor adventurer to the bottom, it is not to be wondered at that he was terrified at the violent agitations in one of these. When his little ship, but ill fitted for opposing the fury of the sea, was got within the vortex, there was then no pes. sibility of ever returning. To add to the fatality, they were al- ways near the shore ; and along the shore was the only place Vi'here this ill-provided mariner durst venture to sail. These were, therefore, dreadful impediments to his navigation ; for if he at- tempted to pass between them and the shore, he was sometimes sucked in by the eddy ; and if he attempted to avoid them out Bt sea, he was often sunk by the storm. But in our time, and in our present improved state of navigation, Charybdis, and the Euripus, with all the other irregular currents ot the Mediternv nean, are no longer formidable. Mr Addison, not attending to this train of thinking, upon passing through the straits of Sicily, was surprised at the little there was of terror in the present ap- pearance of Scylla and Charybdis ; and seems to be of opinion, that their agitations are much diminished since the times of an- tiquity. In fact, from the reasons above, all the wonders of the Mediterranean sea are described in much higher colours than they merit, to us who are acquainted with the more magnificent terrors of the ocean- The Mediterranean is one of the smoothest and most gentle seas in the world •, its tides are scarcely per- THE EARTH. 183 ceivable, except in the gulf of Venice, and ship^vrecks are less known there than in any other part of the world. It is in the ocean, therefore, that these whirlpools are parti cularly dangerous, where the tides are violent, and the tempestf tieree. To mention only one, that called the Maelstroom, upon the coasts of Norway, which is considered as the most dreadfid and voracious in the world. The name it has received from tl e natives, signifies tlie navel of the sea ; since they suppose that ;i great share of the water of the sea is sucked up and dischargea by its vortex. A minute description of the internal parts is not to be expected, since none who were there ever returned to brir^' back mformation. The body of the waters that form this whirl- pool, are extended in a circle above thirteen miles in circumfer- ence. ' In the midst of this stands a rock, against which the tide in its ebb is dashed with inconceivable furj'. At this time it instantly swallows up all things that come within the sphere of its violence, trees, timber, and shipping. No skill in the mariner, nor strength of rowing, can work an escape : the sailor at the helm finds the ship at first go in a current opposite to his intentions ; his vessel's motion, though slow in the beginning, becomes every moment more rapid ; it goes round in circles still narrower, and narrower, till at last it is dashed against the rocks, and instantly disappears : nor is it seen again for six hours ; till the tide flowing, it is vomited forth with the same violence with which it was drawn in. Tiie noise of this dreadful vortex still farther contributes to increase its terror, which, wth the dashing of the waters, and the dreadful valley, if it may be so c:Jled, caused by their circulation, makes one of the most tremendous objects in nature.* 1 Kircher, Mund. .Subt. vn!. i. p. 135. * Sea animals ofuning within the attraotion of this dreadful whirlpool arc nnable to avoid its fury, and various instances are recorded of their strug- gliiig, roaring, and bellowing in a frifrhtful manner, when approachinpr its vortex ; showin'f that they were sensible of their danger. The like happen frequently to bears, which attempt to swim to the island to prey upou the fcheep. There is no doubt of this whirlpool being formed by the accidenta. situation of tlie island of M.iskoe, and the adjacent islands, with the nature and structure of their shores ; the vast body of the Northern ocean forcinfj itself throngh these rocky narrow passages, products this dreadl til vortex, Ofifthe coast of Argyleshire there is a vortex of considerable extent, called the Corbrechtan ; the noise of it can bo he.ird at many milcB, and appears like the distant sound of a number of chariotE. J 84- HISTORY OF CHAP. XVII. OF THE CHANGES PRODUCED BY THE SEA UPON THU EARTH. From what has been said, as well of the earth as of the sea, they both appear to be in continual fluctuation. The earth, the common promptuary that supplies subsistence to men, animals, and vegetables, is continually furnishing its stores to their sup. port. But the matter which is thus derived from it, is soor» restored, and laid down again to be prepared for fresh mutations. The transmigration of souls is, no doubt, false and whimsical ; but nothing can be more certain than the transmigration of bodies : the spoils of the meanest reptile may go to the forma- tion of a prince ; and, on the contrary, as the poet has it, the body of C;esar may be employed in stopping a beer-barrel. From this, and other causes, therefore, the earth is in continual change. Its internal lires, the deviation of its rivers, and the falling of its mountains, are daily altering its surface ; and geography can scarcely recollect the lakes and the valleys that history once described. But these changes are nothing to the instability of the ocean. It would seem that inquietude was as natural to it as its fluidity. It is first seeii with a constant and equable motion going towards the west ; the tides then interrupt this progression, and for s time drive the waters in a contrary direction : beside these agitations, the currents act their part in a smaller sphere, being generally greatest where the other motions of the sea are least ; namely nearest the shore ; the winds also contribute their share in this universal fluctuation •, so tliat scarcely any part of the sea is wholly seen to stagnate. Nil cnim quifiscit, undis impellitur unda, Et spiritus et calor toto se corpore misceiit. As this great element is thus changed, and continually la- bouring internally, it may be readily supposed that it produces correspondent changes upon its shores, and those parts of the earth subject to its influence. In fact, it is every day making considerable alterations, cither by overflowing its shores in one place, or deserting them in others ; by covering over whoii? THE EARTH. 185 tracts of country that were cultivated and peopled, at one time ; or by leaving its bed to be appropriated to the purposes of vege- tation, and to supply a new theatre for human industry, at ano- ther. In this struggle between the earth and the sea for dominion, the greatest number of our shores seem to defy the whole rage of the waves, both by their height, and the rocky materials of which tbey are composed. The coasts of Italy, for instance, are bordered with rocks of marble of different kinds, the quar- ries of which may easily be distinguished at a distance from sea, and appear like perpendicular columns of the most beautiful kinds of marble, ranged along the shore. In general, the coasts of France, from Brest to Bourdeaux, are composed of rocks ; as are also those of Spain and England, which defend the land, and only are interrupted, here and there, to give an egress to rivers, and to grant the conveniences of bays and harbours to our shipping. It may in general be remarked, that wherever the sea is most violent and furious, there the boldest shores, and of the most compact materials, are found to oppose it. There are many shores several hundred feet perpendicular, against which the sea, when swollen with tides or storms, rises and beats with inconceivable fury. In the Orkneys,^ where the shores are thus formed, it sometimes, when agitated by a storm, rises two hun- dred feet perpendicular, and dashes up its spray, together with sand and other substances that compose its bottom, upon land, like showers of rain. From hence, therefore, we may conceive how the violence ct the sea, and the boldness of the shore, may be said to have made each other. '.Vhere the sea meets no obstacles, it spreads its waters with a gentle intumescence, till all its power is destroy- ed, by wanting depth to aid the motion. But when its progress is checked in the midst, by the prominence of rocks, or the abrupt elevation of the land, it dashes with all the force of its depth against the obstacle, and forms, by its repeated violence, that abruptness of the shore which confines its impetuosity. Where the sea is extremely deep, or very much vexed by tem- pests, it is no small obstacle that can confine its rage ; and for this reason we see the boldest shores projected against the 1 Buffon, vt estimate we are disposed to consider as most correct. If so, 100 cubic inches of it, at the temperature of 6C» wlien the barometer stands at 30 inches, weigh 29.83 grains troy. Reckoiiinif the specific gravity of oxygen gas 1.093, and that of azotic gas 0 iHS, and Mijjposiiig atmospherical air to be composed of 79 parts of azote and 21 oxy^'on by bulk, it follows, that 100 parts of it in weight are composed of 77.43 azote 22.57 oxygen 100.00 The third constituent of the atmosphere is carbonic acid gas. Its presence in the atmosphere was rccogni-sed as soon as Dr Black had ascertained the ciiuse of the ditference between raild and caustic alkalies : for it was known, that a caustic alkali soon becomes mild by exposure to the air. Dr Black ascertained, that the mihhie.ss is owing to the absorption of carbonic acid. From the observations of Sanssure « e learn, that this gas exists in the atmo- sphere on the summit of Mount Blanc, which is nearly 1(5,000 feet above the level of the sea; for lime-water soon deposited its lime in the state of caibo- nate, when exposed upon the summit of that mountain, (Saussure's Voyges, iv. 199.) Humboldt found it in a quantity of air bmught down by Garnerin from a height of 4280 feet, to ivhich he had ascended in an air-balloon. {Jour. de Pht/s. xlvii. 202.) It appears, therefore, to constitute a part of every por- tion of the atmosphere to whicli we have access. As this acid gas is pro- duced in great quantities by combustion, respiration, fermentation, and many other of the most common processes of nature, one would be disposed to be. lieve, at first view, that its quantity must be constantly increasing. But this does not appear to be the case ; it must therefore be decomposed and separat- cd from air as fast as it is formed. It is of so deleteriims a nature, that, if it were to accumulate to any extent, it would render air incapable of support, ing life. A candle will not burn in air contaminated with one.ninth of car. bonic acid gits. The quantity of tliis gas in air is small. Many attempts have been made to ascertain it; but the process is so difficult, that absolute pre- cision cannot be looked for. It was long believed that the carbonic acid pre- sent in the atmosphere amounted to one per cent. Humboldt made many experiments on tlie subject, and concluded from them, that its bulk varied from one per cent, tn half a per cent. But this determination is certainly excessive. According to the experiments of Mr Dalton, a quantity of air, equal in bulk to 102,400 grains of water, contains a quantity of carbonic acid just capable of saturating 125 grains of lime-water ; 70 measures of carbonic acid gas would produce the same effect : Hence he concludes, that the atmo. .sphere contains j;^ij^th partof its bulk of carbonic acid gas. {Phil. Mng. xxiii 354.5 Tliis quantity we consider as rather below the truth. Mr Cavendish Till-; KA:(ni. 2'.10 ous supplies ; plants receive arid return tlieir ^liare ; and ani- mals, that by living upon, consnaie this general store, are found to give it back in great quantities when they die.' The air therefore, that we breathe, and upon which we subsist, bears fjas shown, that lime-uater is not capaKle of depriving- air cnmpletely of car. boDic acid gas : Hence a portion would still remain in Mr Dalton's exppri. ment. Perhaps we shall not err far if we state the bulk of carbonic acid gas in the atmosphere at -jQ^jToth part. The 4th constituent of the atmosphere is water in the state of vaponr. That water forms a constituent p.irt of the atmosphere, has been known in all a^res, and indeed is demonstrated by the rain and dew which is continually falling, and by the great quantity of moisture which sulphuric acid, potash, and other bodies, absorb when e.x posed to the atmosphere. The quantity of moisture in the atmosphere has been observed to vary greatly at ditferent times, and various instruments have been invented to measure that quantity. These instruments are called hygrometers. The most ingenious of them are those of Leslie, Saussure, and De Luc. It was at first supposed, that the water in the atmosphere was still in the state of water, and that it was held in solution in air precisely as salts are dissolved in water. But it has been at last established by satisfactory experiments, that the water in the atmosphere is in the state of vapour. To De Luc, Saussure, and Daltou, we are chiefly indebted for these experiments. As to the quantity of water which exists in the atmosphere, it depends upon a variety of circumstances. Saussure found that a cubic foot of air, saturated with moisture at 660, contains about 8 grains troy of water, or g^yth of its weight. Supposing air always satu- 'ated with moisture, the quantity always increases with the temperature, be- cause the elasticity of aqueous vapour increases with the temperature. Hence, in cold weather, the quantity of vapour in air is always small ; whereas, in warm weather, it is often considerable. In the torrid zone the aqueous vapour in the atmosphere is capable of supporting from 0.6 to I inch of mercury. In Britain it is hardly ever capable of supporting 0.6 inch of mercury ; but in summer it is often capable of supporting 0.5 inch, while in winter it often does not exceed 0.1 inch. From these facts it follows, that the weight of water present in the atmosphere varies from J^ to 3-^ of the whole. Mr Daltcii supposes, that the medium quantity of vapour held iu solution at once in the atmosphere, may amount to y^jth of its bulk. - These four bodies, oxygen, azote, carbonic acid, and vapour, are tlie only known constituents of the atmosphere. It cannot be doubted, that other bodies are occasionally present iu it. The dreadful eflects of marshy situ.i. tions upon the health of the inhabitants, and the fatal rapidity with which certain diseases are propagated, cannot well be accounted for, without sup- posing that certain substances which produce a deleterious effect on the ani. mal economy, are occasionally present in the atmosphere. But hitherto no method has been discovered of ascertaining the presence of these bodies, and subjecting them to examination. They are too subtile for our apparatus, and altogether escape the cognizance of our senses. It has been ascertainc<^ 1 Boyle, vol. ii. p. 593. 6 3 210 HISTORY OF very little resemblance to that jnire elementary body which was described in the last chapter ; and which is rather a substance that may be conceived, than experienced to exist. Air, such as we find it, is one of the most compounded bodies in all nature. however, that certain acid fumes, as those of the muriatic acid, nitric acid, and above all, of the oxymuriatic acid, have the property of destroying these miasmata, or at least of preventing them from producing deleterious eflfecta on the animal economy. If the atmosphere were of uniform density, it would be easy to ascertain with the utmost accuracy, the height to which it extends : for the height of the atmosphere would obviously be to the height of the mercury in the barome- ter, as the specific gravity of common air is to the specific gravity of mercury. By making the calculation on this supposition, it will be found that the height of the atumsphere is a little more than 5 miles. As the air, however, gradu- ally diminishes in density, the atmosphere must reach to a much greater distance from the earth than 5 miles. It appears from the duration of twi. light, tliat at the height of H^ miles, the atmosphere is sufficiently dense to intercept the light of the sun, and reflect it to the earth. We are therefore entitled to conclude that it extends to a much greater height. When a ray of light enters the atmosphere, it is bent from its cour.«e by the same cause which refracts the rays of light when they pass through any dense medium, such as glass or water. The refraction sustained by light at its first entrance into the atmosphere must be very small, from the extreme rarity of the air. The deviation, however, will gradually increase as it pene- trates the denser strata, and the ray will describe a path increasing in curva- ture as it approaches the earth. From this property of the atmosphere, the apparent altitude of the sun, moon, and stars, is greater than their real ele- vation, and they appear to bo raised above the horizon when they are actu- ally below 't. The refraction of the atmosphere near the earth's surface is liable to very considerable anomalies. A very extraordinary phenomenon arising from this cause has been described by Mr Vince. The castle of Dover concealed by the hill which lies between it and Ramsgate appeared, on the 6th (if August, 1806, as if it had been brought over and placed on the side of the hill next to Ramsgate. This phenomenon must have arisen from some vr- riation of density in the intermediate air. Phenomena of the same class with the preceding have been illustrated experimentally by the ingenious Dr Wol- (aston. See Edinburgh Transactions, vol. vi. p. 2-15 ; and Phil. Trans. 1778, p. 357 ; 1798 But while the solar rays traverse the earth's atmosphere, they suffer another change from the resisting medium which they encounter. When the sun or any of the heavenly bodies are considerably elevated above the horizon, their light is transmitted to the earth without any perceptible change ; but when these bodies are near the horizon, their light must pass through a long tract of air, and is considerably modified before it reaches the eye of the observer. The momentum of the red or greatest refrangible rays, being greater than the momentum of the violet, or least refrangible rays, the former will force their way through the resisting medium, while the latter will be either reflected or absorbed. A white beam of light, therefore, wilJ by deprived of a portion of its blue rays by its horizontal passage tlirougb THE EARTH. 211 Water may be reduced to a fluid every vvay resembling air, by heat; which, by cold, becomes water again. Everything we see gives off its parts to the air, and has a little floating atmo- sphere of its own round it. The rose is encompassed with a sphere of its own odorous particles ; while the night-shade in- fects the air with a scent of a more ungrateful nature. The perfume ot musk flies off in such abundance, that the quantity rpmaining becomes sensibly lighter by the loss. A thousand substances that escape all our senses we know to be there ; the powerfid emanations of the load-stone, the effluvia of electricity, the rays of light, and the insinuations of fire. Such are the various substances through which we move, and which we are constantly taking in at every pore, and returning again with im- peiceptible discharge ! This great solution, or mixture of all earthly bodies, is con- tinually operating upon itself ; which, perhaps, may be the cause of its unceasing motion ; but it operates still more visibly upon such grosser substances as are exposed to its influence ; for the Htmospliere, and the resulting colour will be either orange or red, ac- -ordiiig to the quantity of the least refrangible rays that have been stopt in t'.ieir course. Hence the rich and brilliant hue with which nature is gilded by the setting sun ; hence the glowing red which tinges the morning and evening clouds ; and hence the sober purple of twilight which they assuma when their ruddy glare is tempered by the reflected azure of the sky. We have already seen, that the redrays penetrate through the atmosphere, while the blue rays, less able to surmount the resistance which they meet, are reflected or absorbed in their passage. It is to this cause that we must ascribe the colour of the sky, and the bright azure which tinges the mountains of the distant landscape. As we ascend in the atmosphere, the deepness of the blue tinge gi-adually dies away ; and to the aeronaut who has soared above the denser strata, or to the traveller who has ascended the Alps or the Andes, the sky appears of a deep black, while the blue rays find a ready passage through the attenuated strata of the atmosphere. It is owing to the same cause that the diver at the bottom of the sea, is surrounded with the red light which has pierced through the superincumbent fluid, and that the blue rays are reflected from the surface of tlie ocean. Were it not for tlie reflecting power of the air, and of the clouds which float in the lower re- gious of the atmosphere, we should be involved in total darkness by the set. ting of the snn, and by every cloud that passes over his disc. It is to the multiplied reflections which the light of the sun suffers in the atmosphere, that we are indebted for the light of day, when the earth is enveloped with impenetrable clouds. From the same cause arises the sober hue of the morn, ing and evening twilight, which increases as we recede from the equaloi till it blesses with perpotual day the inhabitants of the pt.«lar regions. 212 HISTORY OF scincely any substance is found capable of resisting the corrod- ing qualities of the air. The air. say the chemists, is a chaos furnished with all kinds of salts and menstruums ; and, there- fore, it is cajmble of dissolving all kinds of bodies. It is well known, that copper and iron are quickly covered, and eaten with rust , and that, in the climates near the equator, no art can keep them clean. In those dreary countries, the instruments, knives, and keys, that are kept in the pocket, are nevertheless quickly incrusted ; and the great guns, with every precaution, after some years become useless. Stones, as being less hard, may be readily supposed to be more easily soluble. The marble of which the noble monuments of Italian antiquity are composed, although in one of the tinest climates in the world, show the im- pressions which have been made upon them by the air. In many places they seem worm-eaten by time ; and in others, they appear crumbling into dust. Gold alone seems to be ex- empted from this general state of dissolution ; it is never found to contract rust though exposed never so long : the reason of this seems to be, that sea-salt, which is the only menstruum capable of acting upon and dissolving gold, is but very little mix- ed with the air ; for salt being a very fixed body, and not apt to vo- latilize, and rise with heat, there is but a small proportion of it in the atmosphere. In the elaboratories and shops, however, where salt is much used, and the air is impregnated with it, gold is found to nist as well as other metals. Bodies of a softer nature are obviously destroyed by the air.' Mr Boyle says, that silks brought to Jamaica, will, if there ex- posed to the air, rot, even while they preserve their colour ; but if kept therefrom, they both retain their strength and gloss. The same happens in Brazil, where their clothes, which are black, soon turn of an iron colour ; though in the shops, they preserve their proper hue.' In these tropical climates also, such are; the putrescent qualities of the air, that white sugar will sometimes be full of maggots. Drugs and plasters lose their virtue, and become verminous. In some places they are obliged to expose their sweetmeats by day in the sun, otherwise the night-air would quickly cause them to putrify. On the contrary, in the cold arctic regions, animal substances, during the winter 1 BuffoD, vol iii. p. IT2 2 Ibid. vol. iii. p. 6& THE EARTH. 2J3 are never known to putrefy ; and meat may be kept for months without any salt whatsoever. This experiment happily succeed- ed with the eight Englishmen that were accidentally left upon the inhospitable coasts of Greenland, at a place where seven Dutchmen had perished but a few years before ; for killing some rein-deer for their subsistence, and having no salt to pre- serve the flesh, to their great surprise they soon found it did not want any, as it remained sweet during their eight month's con- tinuance upon that shore. These powers with which air is endued over unorganized suD- staiices, are exerted in a still stronger manner over plants, ani- mals of an inferior nature, and lastly over man himself. Most of the beauty and tbe luxuriance of vegetation, is well known to De derived from the benign influence of the air ; and every plant seems to have its favourite climate, not less than its pro- per soil. The lower ranks of animals also seem formed for their respective climates, in which only they can live. ]\Ian alone seems the child of every climate, and capable of existing in all. However, this peculiar privilege does not exempt him from the influences of the air ; he is as much subject to its malignity as the meanest insect or vegetable. With i-egard to plants, air is so absolutely necessaiy for their life and preservation, that they will not vegetate in an exhausted receiver. All plants have within them a quantity of air, which supports and agitates their juices. They are continually imbib- ing fresh nutriment from the air, to increase this store, and to supply the wants which they sustain from evaporation. When, therefore, the external air is drawn from them, they are no longer able to subsist. Even that quantity of air which they before v/ere possessed of, escapes through their pores, into the exhausted receiver ; and as this continues to be pumped asvay, they become languid, grow flaccid, and die. However, tlie plant or flower thus ceasing to vegetate, is kept, by being secured from the external air, a nuich longer time sweet than it would have continued had it been opeidy exposed. Tlxat air which is so necessary to tlie life of vegetables, is still more so to that of animals ; there are none found, how ocemingly torpid soever, that do not require theii' needful supply. Fishes themselves will not live in water from whence the air is ex- hausted ; and it is generally supposed that they die in frozen 214 HisTORr or poiiils, from tlie want of this necessary to animal existence. Many have been the animals that idle curiosity has tortured in the prison of a receiver, merely to observe the manner of their dying. We shall, from a thousand instances, produce that of the viper, as it is known to be one of the most vivacious rep tiles in the world; and as we shall feel but little compassion for its tortures. Mr Boyle took a new caught viper, and shut- ting it up into a small receiver, began to pump away the air.' " At first, upon the air's being drawn away, it began to swell ; gometime after he had done pumping, it began to gape, and open its jaws; being thus compelled to open its jawj, it once more resumed its former lankness j it then began to move up and down within, as if to seek for air, and aftei a wlaile foamed a little, leaving the foam sticking to the inside of the glass ; soon after, the body and neck grew prodigiously tumid, and a blister appeared upon its back ; an hour and a half after, the receiver was exhausted, the distended viper moved, and gave manifest signs of life ; the jaws remained quite distended; as it were from beneath the epiglottis, came the black tongue, and reached beyond it ; but the animal seemed, by its postiue, not to have any life ; the mouth also was grown blackish with- in ; and in this situation it continued for twenty -three hours. But upon the air being re-admitted, the viper's mouth was pre- sently closed, and soon after opened again ; and for some time those motions continued, which argued the remains of life." Such is the fate of the most insignificant or minute reptile that can be thus included. Mites, fleas, and even the little eels that are found swimming in vinegar, die for want of air. Not only these, but the eggs of these animals will not produce in vacuo, but require air to bring them to perfection. As in this mamier air is necessary to their subsistence, so also is must be of a proper kind, and not impregnated with foreign mix- tures. That fictitious air which is pumped from plants or fluids, is generally, in a short time, fatal to them. Mr Boyle has givea us many experiments to this purpose. After having shown that all vegetable and most mineral substances, properly prepai - ed, may afford air, by being placed in an exhausted receiver, and this in such quantities, that some have thought it a new sub- 1 Boyle's riiysico-Mechan. Exper. passim. THc; EARTH. 0J5 tni!Cound, but whicli will seem to proceed from a body situated in a similar posi- tion and distance behind the place of reflection,* as the real sounding body is before it. This reflected sound is commonly called an Echo, which, however, cannot take place at less than fifty-five feet ; because it is necessary that the distance should be such, and the reverberated or reflected sound so long it arriving, that the ear may distinguish clearly between that and the original sound. It is in general kno^vn, that caverns, grottoes, mountains, and ruined build. iDgs, return this image of sound. Image we may call it, for in every respect it resembles the image of a visible object reflected from a polished surface. Our figures are often represented in a mirror without seeing them ourselves, while those standing on one side are alone sensible of the reflection. To bo capable of seeing the reflected image of ourselves, we must be directly in a line with the image. Just so it is in an echo ; we must standiu the line in which the sound is reflected, or the repetition will be lost to us, while it may, at the same time, be distinctly heard by others who stand at a small distance to one side of us. 'i'here is a very extraordinary echo at a ruined fortress near Louvain, in Flanders. If a person sing, he only hears his own voice, but then he hears it with surprising variations, sometimes louder, sometimes softer, now more near, then more distant. There is an account in the Memoirs of the French Academy, of a similar echo near Rouen. 'Ihe building which returns it is a semicircular court-yard ; yet all the buildings of the same form do not pro- duce the same effects. We find some music halls excessively adapted for sounds, while others, built upon the same plan, in a different place, are found to resist the tones, instead of enlarging them, in a very disagreeable manner. As we know the distance of places by the length of time a sound takes to travel from them, ro we may judge of the distance of an echo by the length of the interval between our voice and its repetition. The most deliberate echoes, as they are called, are ever the most di.^tant; while, on the contrary, tlinse that are very near, return their sound so very quick as to linve the iiitHrval almost imperceptible : when this is the case, and the echo is so very near, the voice is said to be increased and not echoed ; however, in fact, the increase is only made by the swiftly pursuing repetition. Our theatres and concert-rooms are best fitted for music or speaking, when they enlarge the sound to the greatest pitch at the smallest interval : for a repetition which does not begin the word till the speaker has finished it, throws all the sounds into confubinn. Thus the theatre at the Hay-market, in London, enlarges the sound very much ; but then at a long interval after the singer or speaker. The old theatre at Drury-lane, before it was altered, enlarged the sound hot * Sound is reflected in the same direction as li^lit from a mirror; that is, the angle of reflection is equal to the angle of incidence. 226 flisTOio OF Those who are willing to augment the catalogue of the bene, fits we receive from this element, assert also, that tastes them- Belves would be insipid, were it not that the air presses their parts upon the nerves of the tongue and palate, so as to produce their gi-ateful effects. Thus, continue they, upon the tops of high mountains, as on the Peak of Teneriffe, the most poignant bodies, as pepper, ginger, salt, and spice, have no sensible taste, for want of their particles being thus sent home to the sensory. But we owe the air sufficient obligationsj not to be studious of admitting this among the number ; in fact, all substances have tlieir taste, as well on the tops of mountains, as in the bottom of the valley; and I have been one of many, who have ate a vei-y savoury dinner on the Alps. It is sufficient, therefore, that we regard the air as the parent of health and vegetation; as a kind dispenser of light and ivarmth ; and as the conveyer of sounds and odours. This is an element of which avarice will not deprive us ; and which power cannot monopolize. The treasures of the earth, the verdure of the fields, and even the refreshments of the stream, are too often seen going only to assist the luxuries of the great ; while the less fortunate part of mankind stand humble spectators of their encroachments. But the air no limitations can bound, nor any landmarks restrain. In this benign element, all mankind can boast an equal possession ; and for this we all have equal obli- gations to Heaven. We consume a part of it, for our own sus tcnance, while we live ; and, when we die, our putrefying bodies give back the supply, which, during life, v.'e had accumulated from the general mass. In a stnall degree ; but then the repetition was extremely quick in its pur- suit, and tlie sounds, when heard, were therefore heard distinctly. Doi^o Use, the great musical composer, used to say, tliat an echo was the hest school-mistress ; for let a man's own music be ever so good, by playing to an echo she would teach him to improve it. Reflected sounds may be magnified by much the same contrivances as are used in optics respectiiifj light : hence it follows, that sounds uttered at one focus of an elliptical cavity, are heard much magnified in t'le other focus. The whispering gallery at St Paul's Cathedral, in London, is of this descrip. tion ; a whisper uttered at one side of the dome is reflected to the other, and may be very distinctly heard. The speaking and ear trumpets are constnn t- ed on this principle The best form for these instruments is a liollow pnrK- holic conoid, with a pmalt orifice at the top or apex, to whii-li the nioutli is applied when the sound is to be magnified, or the ear when the hearing is lo be facilitated. THE EARTH. 227 CHAP. XX. OF WINDS, REGULAR AND IRREGULAR. Wind is a current of" air. Experimental philosophers produce an artificial wind, by an instrument called an ceolipile. This is "nothing more than a hollow copper ball, with a long pipe ; a tea- kettle might be readily made into one, if it were entirely closed at the lid, and the spout left open . through this spout it is to be filled with water, and then set upon the fire, by which means it produces a violent blast, like wind, which continues while there is any water remaining in the instrument. In this man- ner water is converted into a rushing air j which, if caught as it goes out, and left to cool, is again quickly converted into its for- mer element. Besides this, as was mentioned in the former chapter, almost every substance contains some portions of air. Vegetables, or the bodies of animals left to putrefy, produce it in a very copious manner. But it is not only seen thus escap- Mig from bodies, but it may be very easily made to enter into them. A quantity of air may be compressed into water, so as to be intimately blended with it. It finds a much easier admis- sion into wine, or any fermented liquor : and an easier still into spirits of wine. Some salts suck up the air in such quantities, that they are made sensibly heavier thereby, and often are melted by its moisture. In this manner, most bodies being found either j'upable of receiving or affording it, we are not to be surprised at those streams of air that are continually fleeting round the globe. — ]VIiner>Js, vegetables, and animals, contribute to increase the current ; and are sending off their constant sujjplies. These, as they are differently affected by cold or heat, by mixture or putrefaction, all yield different quantities of air at different times; and tlie loudest tempests, and most rapid whirlwinds, are formed from their united contributions. The siin is the principal instrument in rarefying the juices of ]jjaiits, so as to give an escape to their imprisoned air ; it is also equally operative in promoting the putrefaction of animal*. Mineral exhalations are more frequently raised by subterranean heat The moon, the other planets, the seasons, are all com- bined in producing these effects in a smaller degree. Moun- 228 HISTORY or tiiins give a direction to tbe courses of the air. Fires carry a current of air along their body. Night and day alternately chill and warm the earth, and produce an alternate current of its va- pours. These, and many other causes, may be assigned for the variety and the activity of the winds, their continual change, and unceitain duration. With us on land, as the wind proceeds from so many causes, and meets such a variety of obstacles, there can be but little hopes of ever bringing its motions to conform to theory ; or of foretelling how it may blow a minute to come. The great Bacon, indeed, v/as of opinion, that by a close and regular his- tory of the winds, continued for a number of ages together, and the particulars of each observation reduced to general maxims, we might at last come to understand the variations of this ca- pricious element ; and that we could foretell the certainty of a wind with as much ease as we now foretell the return of an eclipse. Indeed, his own beginnings in this arduous undertak- ing seem to speak the possibility of its success ; but, unhappily for mankind, this investigation is the work of ages, and we want a Bacon to direct the process. To be able, therefore, with any plausibility, to account for the variations of the wind upon land, is not to be at present expected; and to understand any thing of their nature, we must have re- course to those places where they are more permanent and steady. This uniformity and steadiness we are chiefly to ex- pect upon the ocean. There, where there is no variety of sub- stances to furnish the air with various and inconstant supplies, where there are no mountains to direct the course of its current, but where all is extensively uniform and even ; in such a place, the wind arising from a simple cause, must have but one simple motion. In fact, we find it so. There are many parts of the world where the winds, that with us are so uncertain, pay their jtated visits. In some places they are found to blow one way by day, and another by night ; in others, for one half of the year they go in a direction contrary to their former course : but, what is more extraordinary still, there are some places where tbe wnids never change, but for ever blow the same way. This is particidarly found to obtain between the tropics in the Atlantic and ^thiopic oceans ; as well as in the great Pacific sea. Few things can appear more extraordinary to a person who THE EARTH. 229 bns never been out of our variable latitudes, than this steady wind, that for ever sits in the sail, sending the vessel forward ; and as effectually preventing its return. He who has been . taught to consider that nothing in the world is so variable as the winds, must certainl)' be surprised to find a place where there is nothing more uniform. With us their inconstancy has become a proverb ; with the natives of those distant climates they may talk of a friend or a mistress as fixed and unchangeable as the winds, and mean a compliment by the comparison. AV^heii our ships are once arrived into the proper latitudes of the great Pacific ocean, the mariner forgets the helm, and his skill becomes almost useless : neither storms nor tempests are known to de- form the glassy bosom of that immense sheet of waters ; a gentle breeze, that for ever blows in the same direction, rests upon the canvas, and speeds the navngator. In the space of six weeks, ships are thus knowTi to cross an immense ocean, that takes more than so many months to return. Upon returning, the trade-wind, which has been propitious, is then avoided ; the mariner is generally obliged to steer into the northern latitudes, and to take the advantage of every casual wind that offers, to assist him into port. This wind, which blows with such con- stancy one way, is known to prevail not only in the Pacific ocean, but also in the Atlantic, between the coasts of Guinea and Brazil ; and, likewise, in the iEthiopic ocean. This seems to be the great universal wind, blowing from the east to the west, that prevails in all the extensive oceans, where the land does not frequently break the general current. Were the whole surface of the globe an ocean, there would probably be but this one wind, for ever blowing from the east, and pursuing the motions of the sun westward. All the other winds seem subordinate to this ; and many of them are made from the de\dations of its cuiTent. To form, therefore, any conception I'elative to the variations of the wind in general, it is proper to begin with that which never varies. There have been many theories to explain this invariable mo- tion of the winds ; among the rest we cannot omit that of Dr Lyster, for its strangeness. " The sea," says he, " in those latitudes, is generally covered over with green weeds, for a great extent; and the air produced from the vegetable peispiration of these, produces the trade- wind." The theory of Cartesius was 230 HISTORY or not quite so absurd. He alleged that the earth went round i'aster than its atmosphere at the equator ; so that its motion, from west to east, gave the atmosphere an imaginary one from east to west ; and thus an east wind was eternally seen to pre- vail. Rejecting those arbitrary opinions, conceived without force, and asserted without proof, Dr Halley has given one more plausible ; which seems to be the reigning system of the day. To conceive his opinion clearly, let us for a moment suppose the whole surface of the earth to be an ocean, and the air en- compassing it on every side, ^^ ithout motion. Now it is evi- dent, that that part of the air which lies directly under the beams of the sun, will be rarified ; and if the sun remained for ever in the same place, there would be a great vacuity in the air, if I may so express it, beneath the place where the sun stood. The sun moving forward from east to west, this vacuity will follow too, and still be made under it. But while it goes on to make new vacuities, the air will rush in to till up those the sun has already made ; in other words, as it is still travelling forward, the air will continually be rushing in behind, and pursue its mo- tions from east to west. In this manner the air is put into mo- tion by day ; and by night the parts continue to impel each other till the next return of the sun, that gives a new force to the cir- culation. In this manner is explained the constant east wind that is found blowing round the globe, near the equator. But it is also known, that as we recede from the equator on either side, we come into a trade-wind, that continually blows from the poles, from the north on one side, or the south on the other, both di- recting towards the equator. This also proceeds from a similar cause with the former ; for the air being more rarified in those places over which the sun more directly darts its rays, the cur- /ents will come both from the north and the south, to fill up the intermediate vacuity. These two motions, namely, the general one from east to west, and the more particular one from both the poles, will ac- count for all the phenomena of trade-winds j which, if the whole surface of the globe were sea, would undoubtedly be constant, and for ever continue to blow in one direction. But there are a thousand circumstances to break these air-currents into smaller ones ; to drive them back against their general course ; to niise THE EARTH. I?31 or depress them ; to condense them into storms, or to whirl them in eddies. In consequence of this, regard must be often had to the nature of the soil, the position of the high mountains, the course of the riversi, and even to the luxuriance of vegetation. If a country, lying directly under the sun, be very flat and sandy, and if the land be low and extensive, the heat occasioned by the reflection of the sunbeams produces a very great rare- faction of the air. The deserts of Africa, which are conform- able to this description, are scarcely ever fanned by a breath of wind by day ; but the burning sun is continually seen blazing in intolerable splendour above them. For this reason, all along the coasts of Guinea, the wind is always perceived blowing in upon the land, in order to fill up the vacuity caused by the sun's operation. In those shores, therefore, the wind blows in a con- trary direction to that of its general current ; and is constantly found setting in from the west. From the same cause it happens, that those constant calms, attended with deluges of rain, are found in the same part of the ocean. For this tract being placed in the middle, between the westerly winds blowing on the coast of Guinea, and the easterly trade-winds that move at some distance from shore, in a contrary direction, the tendency of that part of the air that lies between these two opposite currents is indifierent to either, and so rests between both in torpid serenity ; and the weight of the incum- bent atmosphere, being diminished by the continual contrary winds blowing from hence, it is unable to keep the vapours sus- pended that are copiously borne thither j so that they fall in con- tinual rains. But it is not to be supposed, that any theory can account for all the phenomena of even those winds that are known to be most regular. Instead of a complete system of the trade-winds, we must rather be content with an imperfect history. These,' as was said, being the result of a combination of effects, assume as great a variety as the causes producing them are various. Besides the great general wind above mentioned, in those parts of the Atlantic that lie under the temperate zone, a north wind prevails constantly during the months of October, November, December, and January. These, therefore, are the most favour- 1 JJuIioi;, vol. li. p. 230. V 2 832 HISTORY OF able months for embarking for the East- Indies, in order to take the benefit of these winds, for crossing the Line : and it has been often found by experience, that those who had set sail five months before, were not in the least farther advanced in their \'oyage, than those who waited for the favourable wind. Diirin"' the winter, off Nova Zembla, and the other arctic countries, a north wind reigns almost continually. Li the Cape de Verd islands, a south wind prevails during the month of July. At the Cape of Good Hope, a north-west wind blows during the month of September. There are also regular winds, produced by various causes, upon land. The ancient Greeks were tlie first who observed a constant breeze, produced by the melting o*' the snows, in some high neighbouring countries. This was per- ceived in Greece, Thrace, Macedonia, and the ^gean sea. The same kind of winds are now remarked in the kingdom of Congo, and the most southern parts of Africa. The flux and reflux of the sea also produces some regular winds, that serve the purposes of trade ; and, in general, it may be obsen'ed, that wherever there is a strong current of water, there is a current of air that seems to attend it. Besides these winds that are found to blow in one direction, there are, as was said before, others that blow for certain months of the year one way, and the rest of the year the contrary way ; these are called the Monsoons, from a famous pilot of that name, who first used them in navigation with success.* In all that • Varenii Geographia Generalis, cap. 20. The term Monsoon is other- wise derived from moussin, a Malay word, sigrnifying " season." It is in tlie Indian Ocean alone that the famous monsoons, or half yearly winds, seem to destroy the uniformity of the general atmospheric movement. No doulit, however, they might be made to accord with it, provided we knew all the circumstances which influence them. We exhibit the facts in the first place. From the 10th degree of south latitude to the tropic of Capricorn, and beyond it, the general east or south-east trade wind prevails over all the Indian Ocean, sometimes in summer extending as far as the 2d aud 3d degrees of south latitude. On this side the 10th degree, we first meet with the monsoons or periodical half yearly winds. North of the equator, from April to October, a violent south-vwst wind prevails, accompanied with tempests, storms, and rain ; while a soft and pleasant north-east wind blows during the other six months. Between the second and twelfth parallels of south lati- tude, the winds blow generally from JwriA-uferfduring the winter six months, from south-west in summer. During winter, then, the constitution of the atmosphere exhibits the follow, iiif principal circumstances : North-east winds north of the line ; north- weat THE EARTH. 233 part of the ocean tliat lies between Africa and India, the east winds begin at the month of Januaiy, and continue till about the commencement of June. In the month of August or Sep- tember, the contrary direction takes place : and the west wind ; winds soutli of it, to the lOih parallel: and finally, the east and south-east trade-winds. In summer, the phenomena are less contradictory: South, west wind^ frotn tlie lOth parallel to the northern limits ; trade-winds Boutli of the 10th parallel. These general tendencies arc subject to variations, depending on the figure and elevation of coasts, on straits, and currents of the sea. The north-west and south.wett monsoons am weaker and mure variable in the Bay oJ Een. gaj, more steady and violent in the gulf of Arabia. Both those monsoons grow broader to the west, langing in this direction over the whole tract ot tea that lies between Africa and Madagascar. In the seas extending between China, the kingdom of Siam, Sumatra, and the equator, those monsoons are UM likewise ; but here, excepting local variations, they are almost entirely north and south. Ther extend as far as the Philippine Islands, and though with much inconstancy, even to Japan. Between the equator, the islands of Java, and New Guinea, the monsoons are nearly similar to those of the Chinese Sea, in regard to their direction, which merely varies a little to the north-west in the north munsoon, and a little to the south-west in the south monsoon. But they do not begin till six weeks after those of the Chinese Seas. Some other striking circumstances still remain to be noticed. The mon- soons do not change, or, as t-ailors express it, do not break, of a sudden. Their change, which usually takes plac» fifteen days or four weeks after the equinoxes., is announced by the decay of the existing monsoon, by calms and f quails in rapid succession, by storms, waterspouts, tornadoes, and by Indian hurricanes, called taifnuns, particularly terrible from the explosions of elec- trie matter accumulated by the monsoon. The beginnings of the subsequent monsoon are, at first, liable to variations, till finally it establishes an absolute dominion. Navigators assert, that (m quitting the region where a monsoon prevails, one is sure, in ordinary circumstances, to fall in with a very strong and im- petuous wind, blowing from a quarter directly opposite.- They must natu- rally have observed this phenomenon with much care, since the calms and whirlwinds it occasions are productive of great danger. It can hardly be ex. plained, except by admitting, with Halley, the exibtence of two currents,— one above, compi)?eii of warm and rarified air ; another below, ' onposed o. the column of cold and condensed air. This hypothesis will become almost a settled truth, if we obfcrve how small is the elevation to which the mon. soou extends — a fart clearly exhibited in the peninsula on this side the Gan- ges, where the mcmsoons are arrested for several months by the mountain chain of the Gauts (not certainly of extraordinary height) ; so that the coast of Coromandel, and that of Malabar, have always their dry and their rainy seasons, at opposite periods of tlie year. According to the preceding description, it is the south-west monsoon alone which presents any phenomena directly contrary to the general movement of the atmoEphere ; for the north-east monsoon is in conformity with it, and U ii 2"A HISTORY OF prevail for three or four months. The iMterval between thesp winds, that is to say, from the end of June to the beginning of August, there is no fixed wind ; but the sea is usually tossed by violent tempests, proceeding from the north. These winds are always subject to their greatest variations, as they approach the land ; so that on one side of the great peninsula of India, the coasts are, for near half the year, harassed by violent hurri- canes and northern tempests : while, on the opposite side, and all along the coasts of Coromande), these dreadful tempests are wholly unknown. At Java and Ceylon, a west wand begii.s to reign in the month of September; but at fifteen degrees of tlip north-'.vest wind south of the line seems not to be altogether constant, and may perhaps arise from nothing more than a compound mnvotneiit, or a higher current of air. What then is the originof this half-yearly wind, which in summer blows from south and south-west, over all tlie Indian ocean ? The sagacity of physical geographers has long been exercised by this question. We aive the explanation of which Halley laid the ground-work, and which appears to us the most plausible. The monsoons always change some time after the equinoxes ; they con. stantly blovv towards that hemisphere in which the sun is fouud. The action of this luminary on the atmosphere, is, therefore, plainly one of their causes. When its rays, reflected from the mountains of Thibet, scorching the plains of Bengal, and the valleys of the kingdom of Siam, rarefy and dissipate the atmosphere, the cold air becomes violently attracted from the regions about the south pole. The sun's action is seconded by the marine current, which proceeds from the south polar seas to those of India. This current must bring with it a column of vapours, continually disengaging themselves from its surface. The absence of a northern marine current mu^t farther be added; we can even imagine, that the mountains of Thibet, and the whole central platform of Asia, may arrest and preserve the cold air, which would other. wise proceed from Siberia towards India. But why does not this polar wind prevail south of the equator also ? For the same reason which renders the aquatic polar current inconsiderable there. The general movement of the ocean being opposed by no obstacle, has too much force to be modified by the polar current. A similar result bappen.s ni the atm.osphere, at all times intimately connected with the ocean, which feeds and modifies it. But on leaving New Holland between us and tbc Pacific Ocean, the general movement of the Indian sea must evidently ' more and more abandoned to its individual force, and that force must soon be overcome by the polar current, which, after being long deflected or cou- ceaied by the general movement of the ocean, now re- appears in all its energy. The polar column of water now fills the atmosphere with cold particles, which, by their gravity, determine the whole atmosplieric ma^s to flow towards the equator, more strongly and more directly than it would have flowed otherwise. It is possible, moreover, that higher currents may exist in tlie atmospboro, and descen.! towards the earth at the lime wliea the monsouDB comnK^tcee THE EARTH. 23b south latitude, this wind is found to be lost, and the great gene- ral trade-wind from the east is perceived to prevail. On the contrary, at Cochin, in China, the west wind begins in March ; so that these monsoons prevail, at different seasons, throughout the Indies. So that the mariner takes one part of the year to go from Java to the JMoluccas ; another from Cochin to Molucca ; aiiotlier from Molucca to China ; and still another to direct him from Cliina to Japan. There are winds also that may be considered as peculiar to certain coasts ; for example, the south wind is almost constant upon the coasts of Chili and Peru ; western winds almost con- stantly prevail on the coast of Terra Magellanica, and in the environs of the Straits le Maire. On the coasts of Malabar, north and north-west winds prevail continually ; along the coast of Guinea, the north-west wind is also very frequent ; and, at a distance from the coasts, the north-east is always found prevailing. From the beginning of November to the end of December, a west wind prevails on the coasts of Japan ; and, during the whole winter, no ships can leave the port of Cochin, on account of the impetuosity of the winds that set upon the coast. These blow with such vehemence, that the ports are entirely choked up with sand, and even boats are not able to enter. However, the east winds that prevail for the other half of the year, clear the mouths of their harbours from the accu- mulations of the preceding winter, and set the confined ships at liberty. At the straits of Babelmandel, there is a south wind that periodically returns, and which is always followed by a north-east. Besides winds thus peculiar to certain coasts, there are others found to prevail on all the coasts, in warm climates, which dur- ing one part of the day, blow from the shore, and during an- other part of it blow from the sea. The sea-breeze, in those countries, as Dampier observes, commonly rises in the morning abuut nine, proceeding slowly in a fine small black curl, upon the surface of the water, and making its way to refresh the shove. It is gentle at first, but increases gradually till twelve, then insensibly sinks away, and is totally hushed at five. Upon Us ceasing, the land-breeze begins to take its turn, which in- creases gradually till twelve at night, and is succeeded in the morning by the sea-breeze again. Without all doubt, nothing could be 236 HISTORY OP more fortunate for the inhabitants of the warm coiintncs wherft those breezes blow, than this alternate refreshment, which they feel at those seasons, when it is most wanted. The heat on some coasts would be insupportable, were it not for such a sup- ply of air, when the sun has rarilied all that which lay more im- mediately under the coast. The sea-breeze teniperates the heat of the sun by day •, and the land-breeze corrects the malig- nity of the dews and vapours by night. Where these breezes, therefore, prevail, and they are very common, the nihabitants enjoy a share of health and happiness unknown to those that live much farther up the country, or such as live in similar latitudes without this advantage. The cause of these obviously seems to arise from the rarefaction of the air by the sun, as their dura- tion continues with its appearance, and alters when it goes down. The sun, it is observed, equally diffusing his beams upon land and sea, the land being a more solid body than the water, receives a greater quantity of heat, and reflects it more strongly. Being thus, therefore, heated to a greater degree than the waters, it, of consequence, drives the air from land out to sea ; but its influence being removed, the air returns to fill up the former vacuity. Such is the usual method of accounting for this phenomenon; but, unfortunately, these sea and land breezes are visitants that come at all hours. On the coasts of Malabar,' the land-breezes begin at midnight, and continue till noon ; then the sea-breezes take their turn, and continue till midnight. While again, at Congo, the land-breezes begin at five, and continue till nine the next day. But if the cause of these be so inscrutable, that are, as we sec, tolerably regular in their visitations, what shall we say to the winds of our own climate, that are continually shifting, and in. capable of rest? Some general causes may be assigned, M'hich nothing but particular experience can apply. And in the first place, it may be observed, that clouds and heat, and in short, vk'hatever either increases the density or the elasticity of the air, in any one place, will produce a wind there : for the increased activity of the air thus pressing more powerfully on the parts of it that are adjacent, will drive them forward, and thus go on, in a current, till the whole comes to an equality. i Buflfoii, vol. ii. p. 252. THi; KARTH. 237 In this manner, as a denser air produ<'es a wind, on one hand; so will any accident, that contributes to lighten the air, produce it on the other : for a lighter air may be considered as a vacuity, into which the neighbouring air will rush -. and hence it happens, that when the barometer marks a peculiar lightnes » in the air, it is no wonder that it foretells a storm. The winds upon large waters are generally more regular than those upon land. The wind at sea generally blows with an even steady gale ; the wind at land puffs by intervals, increasing its strength, and remitting it, without any apparent cause. This, in a great measure, may be owing to the many mountains, towers, or trees, that it meets in its way, aU contributing either to turn it from its course, or interrupt its passage. The east wind blows more constantly than any other, and for an obvious reason : all other winds are, in some measure, devia- tions from it, and partly may owe their oiigin thereto. It is generally, likemse, the most powerful, and for the same reason. There are often double currents of the air. While the wind blows one way, we frequently see the clouds move another. This is generally the case before thunder ; for it is well known that the thunder cloud always moves against the wind : the cause of this surprising appearance has hitherto remained a se- cret. From hence we may conclude, that weathercocks only inform us of that current ot the air which is near the surface of the earth ; but are often erroneous with regard to the upper re- gions, and, in fact, Derham has often found them erroneous. "Winds are generally more powerful on elevated situations than on the plain, because their progress is interrupted by fewer ob- stacles. In proportion as we ascend the heights of a mountain, the violence of the weather seems to increase, until we have got above the region of storms, where all is usually calm and serene. Sometimes, however, the storms rise even to the tops of the highest mountains ; as we learn from those who have been on the Andes, and as v,e ai'e convinced by the deep snows that croHii even the highest. Winds blowing from the sea are generally moister, and more attended with rains, than those which blow over extensive tracts of land ; for the sea gives off more vapours to the air, and these are roiled forward upon land by the wind's blowing irom 238 HISTOR1 OF thence.' For this reason our easterly winds that blow from the continent are diy in comparison of those that blow from the sur- face of the ocean, with which we aie surrounded on every other quarter. In general the winds are more boisterous in spring and autumn than at other seasons : for that being the time of high tides, the sea may communicate a part of its motions to the winds. The sun and moon, also, which then have a greater ef- fect upon the waters, may also have some influence upon the winds : for there being a great body of air surrounding the globe, which, if condensed into water, would cover it to the depth of thirty-two feet, it is evident that the sun and moon will, to a proportionable degree, affect the atmosphere, and make a tide of air. This tide will be scarcely perceivable, indeed; but, without doubt, it actually exists ; and may contribute to in- crease the vernal and autumnal storms, which are then known to prevail. Upon narrowing the passage through which the air is driven, both the density and the swiftness of the wind is increased. For, as currents of water flow with greater force and rapidity by narrowing their channels ; so also will a current of air driven through a contracted space, grow more violent and irresistible. Hence we find those dreadful storms that prevail in the defiles of mountains, where the wind, pushing from behind through a narrow channel, at once increases in speed and density, levelling or tearing up every obstacle that rises to obstruct its passage. Winds reflected from the sides of mountains and towers, are often found to be more forceful than those in direct progression. This we frequently perceive near lofty buildings, such as churches or steeples, where winds are generally known to prevail, and thai much more powerfully than at some distance. The air in this case, by striking against the side of the building, acquires addi- tional density, and, therefore, blows with more force. These diflferent degrees of density, which the air is foimd to possess, suificiently show that the force of the winds do not depend upon their velocity alone ; so that those instruments called anemometers, which are made to measure the velocity oi the wind, will by no means give us certain information of the i Derham'o I'liysini-Theoi. THE EAPaH. 239 force of the storm. In order to estimate this with exactness, we ought to know its density ; which also these are not calcu- lated to discover. For this reason we often see storms, with very powerful effects, that do not seem to show any great speed ; and, on the contrary, we see these wind-measurers go round with great swiftness, when scarcely any damage has followed from the storm. Such is the nature and the inconstancy of the irregular winds, with which we are best acquainted. But their effects are much more formidable in those climates near the tropics, where they are often found to break in upon the steady course of the trade- winds, and to mark their passage with destruction. "With us the tempest is but rarely known, and its ravages are registered as an 'mcommon calamity ; but in the countries that lie between the tropics, and for a good space beyond them, its visits are fre- quent, and its effects are anticipated. In these regions the winds vary their terrors; sometimes involving all thing in a suffocating heat; sometimes mixing aU the elements of tire, air, earth, and water, together; sometimes, with a momen- tary swiftness, passing over the face of the country, and destroy- ing all things in their passage ; and sometimes raising whole sandy deserts in one country, to deposite them upon some other. We have little reason, therefore, to envy these climates the luxiu-iance of their soil, or the brightness of their skies. Our own muddy atmosphere, that WTaps us round in obscurity, though it fails to gild our prospects with sunshine, or our groves with fruitage, nevertheless answers the call of industry. They may boast of a plentiful, but precarious, harvest ; while with us, the labourer toils in a certain expectation of a moderate, but a happy, return. In Egypt,* a kingdom so noted for its fertility, and the bright- ness of its atmosphere, during summer, the south winds are so hot, that they almost stop respiration ; besides which, they aie charged with such quantities of sand, that they sometimes darken the air as with a thick cloud. * 2 Buffon, vol. ii. p. £58. * The most destructive wind of Egypt is what is railed the Kamsin, which generally prevails in March, April, and May. Denon thus describes it : " The Kamsin is equally terrible by the frigntful spectacle which it exiiihita when present, and by the consequences wh'ch follow its ravages. vVe haii already passed with security one h;ilf of the season in which it Ujually ?4)0 HISTORY OF These sands are so fine, and driven wdth such \-io!ence, that tliey penetrate every where, even into chests, be they shut never so closely. If these vidnds happen to continue for any length oi time, they produce epidemic diseases, and are often followed by a great mortality. It is also found to rain but very seldom in that country ; however, the want of showers is richly compen- sated by the copiousness of their dews, which greatly tend to promote vegetation. In Persia, the winter begins in November, and continues till March. The cold at that time is intense enough to congeal the water ; and snow falls in abundance upon their mountains. appears : «'hen, in tlie evening- of the 18th of May, I felt myself entirely overcome by a suit'ofating' lieat ; it seemed as if the fluctuation of the air was Biiddenly suspended. I was struck on my arrival with my companions at the bank of the Nile, with a new appearance of Nature all around me ; this was a kind of light and colours which I liad not before seen. 'J'he sun, without being concealed, had lost its rays ; it had even less lustre to the eye than the tiioon, and gave a pale light without shade ; the waters of the Nile no longer reflected its rays, but appeared in agitation ; every thing had changed its usual aspect ; it was now the flat shore that seemed luminous, and the air dull and opaque; the yellow horizon showed the trees on its surface of » dirty blue ; flocks of birds were flying off before the cloud : and frighted ani- mals ran loose in the country, followed by the inhabitants, who vainly attempted to collect them together again. We could now easily conceive the dreadful situation of those who are surprised with such a phenomenon of nature, when crossing the exposed and naked deserts ; where, as it stands upon record, many thousands have been overwhelmed and lost in the shoals of sand raised by the Kamsin winds. The next day an astonishing mass of dust, attended with similar appearances, travelled along the desert of Libya : it followed the chain of the mountains, and when we flattered ourselves that we were entirely rid of this pestilence, the west wind brought it back, and once more overwhelmed us with this scorching torrent ; the light of the sun could pierce with difficulty through this dense vapour ; all the elemeiUs appeared to be in disorder ; rain was mixed with whirlwinds of fire, wind, add dust, and, in this time of confusion, the trees, and all the other produc- tions of nature, seemed to be again plunged in the horrors of chaos. If the desert of Liyba had sent ns these clouds of dust, those on the east, on the contrary, had been inundated with water; for the merchants who came from .he borders of the Red Sea, told us, that in the valleys, they had the water up to the middle of their legs. When this destructive scourge sets in from the desert, the inundation of sand often overwhelms the country, changes its fertility to barrenness, drives the labourer from his house, whose walls it covers up, and leaves no other mark of vegetable life but the tops of a few palm-trees, which adds still more to the dreary aspect of destruction. Thus the desert is constantly encroaching on the fertile land ; and, were the waters of the Nile to discontinue its inundations, the whole vale of Egypt would eventually become a desert or bed of sand." THE EAIiTH. 241 Vhirmg the months of March and Apiil, winds arise, that blow with great force, and seem to usher in the heats of summer. These return again, in autumn, with some violence ; without, however, producing any dreadful effects. But during their sum- mer, all along the coasts of the Persian Gulf, a very dangerous wind prevails, which the natives call the Sameyel, still more dreadful and burning than that of Egypt, and attended with instant and fatal effects. This terrible blast, which was, perhaps, the pestilence of the ancients, instantly kills all those that it in- volves in its passage. What its malignity consists in, none can tell, as none have ever survived its effects, to give information.* It frequently, as I am told, assumes a visible form, and darts, in a kind of bluish vapour, along the surface of the countrj'. The natives, not only of Persia, but of Arabia, talk of its effects with terror ; and their poets have not failed to heighten them with the assistance of imagination. They have described it as under the conduct of a minister of vengeance, who governs its terrors, and raises or depresses it, as he thinks proper.' These deadly winds are also known along the coasts of India, at Nega- patam, Masulipatam, and Petapoli. Eut, luckily for mankind, the shortness of their duration diminishes the injuries that might ensue from their malignity. The Cape of Good Hope, as well as many islands in the West- Indies, are famous for their hurricanes, and that extraor- dinary kind of cloud which is said to produce them. This cloud, vk^hich is the forerunner of an approaching hurricane, appears, when first seen, like a small black spot, on the verge of the hori- zon ; and is called, by sailors, the bull's eye, from being seen so minute at a vast distance. f All this time a perfect calm reigns over the sea and land, while the cloud grows gradually broader as it approaches. At length, coming to the place where its fury is to fall, it invests the whole horizon with darkness. • It ia said of this wind, that if it happens to meet with a shower of rain in tts course, and blows across it, it is at once deprived of its noxious quality, and becomes mild and innocent. It is also said, that it was never known to pass the walls of a city. Its fatal effects probably proceed from a certain portion of extremely putrid vapours wth whicli it is charged, by blowing over gome very putrid and stagnant lake. 2 Herbelot, Bibliotheque Oriental. t The water spout or syphon, is a no less dangerous phenomenon. An ac- c-iiurit of it will be found in the succeeding chapter. X 212 VIISTORY OF During all the time of its approach, a hollow murmur is heara in the cavities of the mountains ; and beasts and animals, sensible of its approach, are seen running over the fields, to seek for shelter. Nothing can be more terrible than its violence when it begins. The houses in those countries, which are made of tim- ber, the better to resist its fury, bend to the blast like osiers, and again recover their rectitude. The sun, which but a mo- ment before blazed with meridian splendour, is totally shut out ; and a midnight darkness prevails, except that the air is inces- santly illuminated with gleams of lightning, by which one can easily see to read. The rain falls, at the same time, in torrents; and its descent has been resembled to what pours from the spouts of our houses after a violent shower. These hurricanes are not less offensive to the sense of smelling also, and never come without leaving the most noisome stench behind them. If the seamen also lay by their wet clothes, for twenty-four hours, they are all found swarming with little white maggots, that were brought with the hurricane. Our first mariners, when they visited these regions, were ignorant of its effects, and the signs of its approach ; their ships, therefore, were dashed to the bot- tom at the first onset ; and numberless were the wrecks which the hurricane occasioned. But, at present, being forewarned of its approach, they strip their masts of all their sails, and thus patiently abide its fury. These hurricanes are common in all the tropical climates. On the coasts of Guinea they have fre- quently three or four in a day, that thus shut out the heavens for a little space ; and, when past, leave all again in former sjilendour. They chiefly prevail, on that coast, in the intervals of the trade-winds; the approach of which clears the air of its meteors, and gives these mortal showers that little degree of wholesomeness which they possess. They chiefly obtain there during the months of April and May; they are known, ar Loango, from January to April ; on the opposite coast of Africa, the hurricane season begins in May; and, in general, whenever a trade-wind begins to cease, these irregular tempests are found to exert their fury. All this is terrible ; — but there is a tempest known in those climates, more formiduble than any we have hitherto been des- cribing, which is called, by the Spaniards, a Tornado. A& the former was seen arriving from one part of the heavens, thus THE EARTH. 243 making a line of destruction ; so the winds in tliis seem to blow from every quarter, and settle upon one destined place, with such fury, that nothing can resist their vehemence. When they have all met, in their central spot, then the whirlwind begins with ciicular rapiditj'. The sphere every moment widens, as it continues to turn, and catches every object that lies within it3 attraction. This also, lilie the former, is preceded by a flatter- ing calm ; the air is ever)' where hushed, and the sea is as smooth as polished glass : however, as its effects are more dreadful than those of the ordinary hurricane, the mariner tries all the power of his skill to avoid it ; which, if he fails of doing, there is the greatest danger of his going to the bottom. All along the coasts of Guinea, beginning about two degrees north of the Line, and so downward, lengthwise, for about a thousand miles, and as many broad, the ocean is unnavigable, on account of these tor- nadoes. In this torrid region there reigns unceasing tornadoes, or continual calms; among which, whatever ship is so unhappy as to fall, is totally deprived of all power of escaping. In this dreadful repose of all the elements, the solitary vessel is obliged to continue, without a single breeze to assist the mariner's wishes, except those whirlwinds, which only serve to increase his calamity. At present, therefore, this part of the ocean is totally avoided; and, although there may be much gold along the coasts of that part of Africa, to tempt avarice, yet there is something, much more dreadful than the fabled dragon of anti quity, to guard the treasure. As the internal parts of that country are totally unknown to travellers, from their burning sand and extensive deserts ; so here we find a vast tract of ocean, lying off its shores, equally unvisited by tlie mariner. But of all these terrible tempests that deform the face of nature, and repress human presumption, the sandy tempests oi Arabia and Africa are the most terrible,* and strike the imagi- » In his travels to discover the source of the Nile, Mr Bruce observed the astonishing phenomenon of moving pillars of sand, whirh are probably the effects of a number of whirlwinds in those torrid regions. In relating the particulars of his journey across a part of the deserts of Africa, he ob. oerves, " We were here at once surprised and terrified with a sight surely one of the most magnificent in the world. In that vast expanse of desert, from west and to the north-west of us, we saw a number of prodigious pi|. .ara of sand at different distances, at times moving with great celerity, and »t others stalking ou with a majestic sImm np=-- ; at interv;ils we tliought thej X 2 244. HISTORY or nation most strongly. To conceive a proper idea of these, \re are by no means to suppose tbem resembling those whirlwinds of dust that we sometimes see scattering in our air, and sprink- ling their contents upon our roads or meadows. The sand- uere coming in a very few minutes to overwhelm us ; and small quantities of sand did actually more than once reach us. Again they would retreat, so as to be almost out of sight, their tops reaching to the very clouds. There tlie tops often separated from the bf)dies, and these once disjoined, dispersed in the air, and did not appear more. Sometimes they were broken near the middle, as if struck with a large cannon shot : about noon they began to ad. vance with considerHhlo swiftness upon us, the wind being very strong at north. Eleven of them ranged alongside of us, about the distance of three miles. The greatest diameter of the largest appeared to me at that distance as if it would measure ten feet. They retired from us with a wind at south- east, leaving an impression upon my mind to which I can give no name, though surely one ingredient in it was fear, with a considerable deal of won- der and asvonishment. It was in vain to think of flying ; the swiftest horse, or fastest sailing ship could be of no use to carry us out of this danger ; and the full persuasion of this rivetted me as if to the spot where 1 stood, and let the camels gain on me so much in my state of lameness, that it was with some difficulty I could overtake them. The saice phenomenon occurred again in the course of a few days. The same appearance of moving pillars of Band presented themselves to us tliis day, in form and disposition like those we had seen at Waadi Halboub, only they seemed to be more in numbiTand less in size. They came several times in a direction close upon us ; that is, I believe within less than two miles. They began immediately after sun-rise like a thick wood, and almost darkened the sun : his rays shining through them for near an hour, gave them an appearance of pillars of fire. Our people now became desperate, the Greeks shrieked out, and said it was the day of .iudgment. Ismael pronounced it to be hell, and the Tucorories that the world was on fire. I asked Idris if ever he had before s«en such a sight ? He «aid he had often seen them as terrible, though never worse ; but what he feared most was the extreme redness of the air, which was a sure presage of the coming of the simoom. I begged and entreated Mris that he would not eay one word of that in the hearing of the people, for they had already felt it at Imhaosara, on their way from Rhs el Feel to Teawa, and again at the Acaba of Gerri, before we came to Chendi, and they were already nearly di3» tracted at the apprehension of finding it here. On the 16th, at half-past ten in the forenoon, we left El Mout, standing io the direction close upon Syene. At eleven o'clock, while we contemplated with pleasure the rugged top of Chiggne, to which we were fast approach. ff, and where we were to solace ourselves with plenty of gnod water, Idrjs cried out with a loud voice, Fall upon your faces, for here is the simoom. I saw from the south-east a haze come, in colour like the purple part of the rainbow, but not so compressed or thick. It did not occupy twenty yards in breadth, and was about twelve feet high from the ground. It was a kind of blush upon the air, and it moved very rapidly, for I scarce could turn to fall upon the ground with my head to the northward, when I felt the heat of itg rurrent plainly upon ray face. We all l:iv H.il upon tlie ffnmnd, till Idris told THE EAKTB. 245 Btoim of Africa extibits a very different appearance. As the Band of which the whirlwind is composed is excessively fine, and almost resembles the parts of water, its motion entirely resembles that of a fluid ; and the whole plain seems to float onward, like a slow inundation. The body of sand thus rolling, is deep enough to bury houses and palaces in its bosom : travellers who are crossing those extensive deserts perceive its approach at a distance ; and in general have time to avoid it, or turn out of its way, as it generally extends but to a moderate breadth. How- ever, when it is extremely rapid, or very extensive, as sometimes is the case, no swiftness, no ^t, can avail ; nothing then remains but to meet death with fortitude, and submit to be buried alive with resignation. It is happy for us of Britain that we have no such calamity to fear :* for from this even some parts of Europe are not entirely u* it «as blown over. The meteor or purple haze which I saw, was indeed past, but the light air that still blew was of heat to threaten suffocation. For my part, I f'jund distinctly in my breast that I had imbibed a part of it ; nor was I free of an asthmatic sensation till I had been some months in Italy, at the baths of Poretta, near two years afterwards. * One of the most dreadful storms which this island ever experienced was that which took place ou the 27th Nov. 1703. This tempest was preceded by a strong west wind which set in about the middle of the month ; aud every day, and almost every hour, increased in force until the 24th, when it blew furiously, occasioned much alarm, and some damai^e was sustained. On the 25th, and through the night follo\ving, it continued with unusual violence. On the morning of Friday, the 26th, it raged so fearfully that only few people had courage to venture abnad. Towards evening it rose still higher ; the night setting in with excessive darkness added general horror to the scene, and prevented any from seeking security abroad from their homes, had that been possible. The extraordinary power of the wind created a noise, hoarse and dreadful. Tike thunder, which carried terror to every ear, and appalled every heart. Tliere were also appearances in the heavens that resembled lightning. " The air," says a writer at the time, " was full of meteors and fiery vapours; yet," he adds, " I am of opinion, that there was really no lightning, ia the common acceptation of the term ; for the clouds, that flew with such violence through the air, were not to my observation such as are usually freighted with thunder and lightning ; the hurries nature was then in, do not consist with the system of thunder.". Some imagined the tempest svas accompanied with an earthquake. " Horror and confusion seized upon all, whether on snore or at sea : no pen can describe it, no tongue can express it, no thongh can conceive it, unless theirs who were in the extremity of it ; and who, be. ing touched with a due sense of the sparing mercy of their Maker, retain the deep impressions of his goodness upon their minds though the danger be past To venture abroad was to rush into instant death, and to stay within afforded uo other prospect than that of being buried under the ruins of a fulliD),' habi. X. 3 246 IIISTOHY OF free. We have an account given us in the history of the French Academy, of a miserable town in France, that is constantly in dan- ger of being buried under a similar inundation ; with which I will take leave to close this chapter. " In the neighbourhood of St tntion. Some in their distraction did the former, and met death in the streets ; others the latter, and in tlieir own houses received their final doom." One hundred and twenty. three persons were killed by the falling of dwell, ings ; amongst these were the bishop of Bath and Wells (Dr Richard Kidder) and his lady, by the fall of part of the episcopal palace of Wells : and lady Penelope Nicholas, sister to the bishop of London, at Horsley, in Sussex. Those whoperished in the waters, in the floods of the Severn and the Thames on the coast of Holland, and in ships blown away and never heard of after- wards, are computed to have amounted to eight thousand. All ranks and degrees were affected by this amazing tempest, for every family that had any thing to lose lost something : laud, houses, churches, corn, trees, rivers, all were disturbed or damaged by its fury j small build- iugs were for the most part wholly swept away, " as chatf before the wind." Above eight hundred dwelling-houses were laid in ruins. Few of those that resisted escaped from being unroofed, which is clear from the prodigious increase in the price of tiles, which rose from twenty-one shillings to six pounds the thousand. About two thousand stacks of chimneys were blown down in and about London. When the day broke, the houses were mostly stripped, and appeared like so many skeletons. The consternation was so great that trade ami business were suspended, for the first occupation of the mind was so to repair the houses, that families might be preserved from the inclemency of the weather in the rigorous season. The streets were cover- ed with brickbats, broken tiles, signs, bulks, and pent-houses. The lead which covered one hundred churches, and many public buildings, was rolled up, and hurled in prodigious quantities to distances almost incredi- ble; spires, and turrets of many others were thrown down. Innumerable stacks of corn and hay were blown away, or so torn and scattered as to re- ceive great damage. Multitudes of cattle were lost In one level in Gloucestershire, on the banks of the Severn, fifteen thousand sheep were drowned. Innumerable trees were torn up by the roots ; one writer says, that he himself nurabeied seventeen thousand in part of the county of Kent alone, and tliat, tired with counting, he left off reckoning. The damage in the city of London alone, was computed at near two mil- lions sterling. At Bristol, it was abotlt two hundred thousand pounds. In the whole, it was supposed, tliat the loss was greater than that produced by the great fire of London, 1666, which was estimated at four millions. The greater part of the navy was at sea, and if the storm had not been at Its height at full flood, and in a spring-tide, the loss might have been nearly fatal to the nation. It was so considerable, that fifteen or sixteen men of war were cast away, and more than two thousand seamen perished. Few mar. chantmen were lost : for most of those that were driven to sea were safe Kear-admiral Beaumont, with a squadron then lying in the Downs, perished with his own and several other ships on the Goodwin Sands 'the shiit lost by the storu) vvere eDtiiniited at three hundred. lu tho nysr THK EARTH. 247 Paul de Leon, in Lower Brittany,' there lies a trace of country along the sea-side, which, before the year 1666, was inhabited, but now lies deserted, by reason of the sands which cover it, to the height of twenty feet ; and which every year advance more and Thames, only four ships remained between London-bridge and Limehouse, the rest being driven below, and lying there miserably beating against one another. Five hundred wherries, three hundred ship. boats, and one hundred hghters and barges were entirely lost ; and a much greater number received considerable damage. The wind blew from the western seas, which preven. ting many ships from patting to sea, and driving others into harbour, occa. Bioned great numbers to escape destruction. The Eddystone lighthouse near Plymouth was precipitated in the surround, ing ocean, and with it Mr Winstanley, the ingenious architect by whom it was contrived, and the people who were with him. — " Having been frequent- ly told that the edifice was too slight to withstand the fury of the winds and waves, he was accustomed to reply contemptuously, that he only wished to be in it when a storm should happen. Unfortunately his desire was gratified. Signals of distress were made, but in so tremendous a sea no vessel could live, or would venture to put off for their relief."* The amazing strength and rapidity of the wind, are evidenced by the fol. lowing well authenticated circumstances. Near Shaftesbury a stone of near four hundred pounds weight, which had lain for some years fixed in the ground, fenced by a bank with a low stone wall upon it, was lifted up by the wind, and carried into a hollow way, distant at least seven yards from the place. This is mentioned in a sermon preached by Dr Samuel Stennett in 1788. Dr Andrew GiflFord, in a sermon preached at Little Wylde-street, on the 27th of November, ITSi, says, that " in a country town, a large stable was at once re. moved off its foundation, and instantly carried quite across the highway, over the heads of five horses and the man that was then feeding them, without hurting any one of them, or removing the rack and manger, both of which remained for a considerable time to the admiration of every beholder." Dr Gifford, in the same sermon, gives an account of " several remarkable deliver, ances." One of the most remarkable instances of this kind occurred at a house in the Strand, in which were no less than fourteen persons: "Four of them fell with a great part of the house, &c. tJiree stories, and several two : and though buried in the ruins, were taken out unhurt ; of these, three were children ; one that lay by itself, in a little bed near its nurse; another in a cradle; and the third was found hanging (as it were wrapp'd up) in some curtains that hitch'd by the way ; neither of whom re- ceived the least damage. In another place, as a minister was crossing a court near his house, a stone from the top of a chimney, upwards of one hundred and forty pounds weight, fell close to his heels, and cut between his footsteps four inches deep into the ground. Soon after, upon drawing in his arm, which he had held out on some occasion, another stone, of near the same weight and size, brushed by his elbow, and fell close to his foot, wluch must necessarily, in the eye of reason, have killed him, had it fallen while it was 1 Histoire