THE MYSTERIES OF THE OCEAN.*
Jr is not so clear for what class of readers this work is intended. It has been translated, edited, and enlarged from the French of Arthur Mangin, by the translator of The Bird, who tells us in the preface that "he trusts it will be considered an agreeable and useful addition to the family library, and a convenient manual for the general reader." The style of the publication is, however, much too handsome, and the matter too little exact or systematic to fit it for a scientific manual, or even to qualify it for the family library. Probably it would rather serve to ornament a drawingroom. The form in which it is edited is unexceptionable, and the illustrations of Mr. Freeman are most excellent. Yet the absolute solidity of the subject-matter must rather unfit it to grace the drawing-room table by the side of such books as the Lalla Rookh adorned by the illustrations of Tenniel, or the "Wordsworth," by those of Birket Foster. The British daughter, beguiled by its external seductions, instead of enjoying an hour of light mental dalliance, would be suddenly confronted by the correct theory of geogenesis, M. Adhe'mar's complicated explanation of glacial submergence, the evidences of a deity, and other subjects equally recondite. We feel like poor Master Tozer in Dombey and Son. "Toner had an uncle who not only volunteered examinations of him, in the holidays, on abstruse points, but twisted innocent events and things and wrenched them to the same fell purpose. So that if this uncle took him to the play, or on a similar pretence of kindness carried him to see a giant, or a dwarf, or a conjuror, or anything, Tozer knew he had read up some classical allusion to the subject beforehand, and was thrown into a state of mortal apprehension, not foreseeing where he might break out or what authority he might quote against him." This same feeling of distrust disturbs the reader in the enjoyment during an idle hour of the really attractive writing and general matter of the book, lest the next page may obtrude upon his attention some very abstruse calculation, or some revolutionary theory such as that of M. Paul Laurent on the origin of vegetables. Still, any attempt to Introduce into the demesne of more trivial pleasures a taste for subjects of real speculative interest is, so far, a useful and laudable experiment, and deserves every support.
The whole subject-matter is divided into five books. The first Considers "The History of the Ocean," the sequence of causes which have determined the fact and the mode of its existence.
Glancing at the epoch at which our whole solar system was a mass of nebulous matter rotating on its axis, we notice the nuclei of more aggregate matter, the future planets forming in it as it Cools; these nuclei getting always more and more detached from one another, but still of course revolving in situ as when they were Parts of the whole ; perhaps in some of them other nuclei collecting and forming satellites, until finally "we take as the startingpoint of our history of the ocean that moment in the dim long ago, when after millions of years the globe which we inhabit was still an assemblage of burning vapour revolving in space." This is., of coarse, substantially the theory of Laplace, nowhere more Simply stated than in the Vestiges of Creation. Some of the vapours condense and meet to form a liquid nucleus at the centre, while the immense gaseous envelope contracts more closely around. A 'runt begins to form, first, where the heat of the sun is least, at the palm, already somewhat flattened, owing to the lateral rotation of the central liquid. At last, even the bulging at the equator, where both heat and centrifugal force are greatest, is itself confined by a solid crust, and the so-called Brute period is at an end. Two gases, hydrogen and oxygen, existing in immense quantities, in the atmosphere, had combined during the incandescent period to form water, not in a liquid state as yet, but in vapour. But the atmosphere sinks below the temperature of boiling water. Water now becomes liquid, and precipitates itself upon the crust of the earth. Contact with the burning soil evaporates it again at first, to be again condensed and fall, this time on a cooler basis. At last it is allowed to rest there, the ocean begins to exist, and the formation of aqueous strata becomes possible. Sir Humphrey Davy has remarked that at the first precipitation of the waters, the oxydable metals near the surface must have resolved it into its elements, united with the oxygen, and produced a general conflagration. Alkalis and earths are the result, which again fix the acids and produce salts. The writer says :— " If we take account of the composition of the various rocks, notably the calcareous rocks which are so widely distributed in the world's crust, and the abundance of certain salts with an alkaline or earthy base dissolved in the ocean waters, or forming vast deposits in the soil, we cannot deny that Davy's hypothesis wears an aspect of great probability."
The heavier substances, salts of lime, iron, clay, and siliceous sand, now fall to the bottom. One very important salt remains in solution. This is the common sea salt, a combination of the metal sodium and the gas chlorine. "Whether this was formed in a dry state during the igneous period, or during the aqueous period in a humid one, it is no longer doubted but that it made part of the composition of sea water even in the beginning." The proportion of salt in the water is little over 3 per cent. Yet if all this salt were extracted and heaped together it would form a mountain whose base would occupy the whole of North America, while its peak would reach a height of 5,000 feet. At this point, then, the chemical constitution
of the earth is little different from its present. But the temperature is much higher, organic life does not yet exist, and the present distribution of land and water has yet to develop. M. Mania supposes that the waters still cover the earth, and as yet no upheaval of the land has taken place. At last the temperature at the earth's surface sinks to 122° Fehr. This is the point at which
albumen coagulates. Organic life begins to be possible, and a new and important era commences.
Professor Houghton has ventured to approximate to the length of this first period of the ocean's existence. The time of cooling from 212° Fahr., the temperature at which the sea was condensed, to 1220, at which albumen coagulates, supposing the heat of the sun no greater than at present, would be 1,018 millions of years. This is a moderate conclusion, for as the sun must also have been growing cool, its greater heat during the period in question would considerably retard the cooling of the earth. M. Mangin now proceeds to upheave the crust. The outline of the Irish coast and the Malvern and Welsh hills appear above the surface of the water. The old granite drags up with it the earliest stratified rocks, against which the great ocean will throw up a wide beach of red shingle and lower Silurian mud. As yet, the animal and vegetable kingdoms are represented only by algte, fucoids, and zoophytes. The simplest molluscs have hardly begun to exist. At this point the histories of the ocean and of land cease to be the same. The further history of terra firma is foreign to the subject of the book, except where its geographical outline is modified by the action of
ocean currents. M. Mangin, however, thinks it necessary to examine into the cause of certain traditional invasions on an immense scale of the sea on the land, viz., the deluges. He does not question the fact, for which he considers the fossil
shells found on the lofty summits of mountains sufficient evidence. He does not mention the names or age of these mountains. Shellfish were in existence as early as the Llandeilo rocks. The mountain formations in which the shells are found are not likely to be older than this. Evidence that terrestrial remains underlie them would be necessary, though not itself quite conclusive, to meet the primil facie improbability of such an abnormal catastrophe. Ile continues :— " The upheavals and depressions of the terrestrial crust are not the only causes which may be assigned for the displacement of the MU. There are facts evidently diluvian for which these phenomena do not satisfactorily account. There aro others much more general and more important which have convulsed the soil, effected immense destruction of living beings, drawn from one pole to the other the rush of devastating waters, changed the distribution of temperature, and overthrown the inorganic and organic economy of the globe's surface."
He advances the discovery of carcases in Siberia, with flesh and hair preserved, evidently through the agency of frost before putrefaction could set in ; a frost which could not have prevailed ordi
nosily in the localities in which they perished, as they could not have existed in it. This is considered proof of the suddenness of its invasion. But there is nothing in this which a local glacial invasion at the most could not have occasioned. And the original submarine deposition of strata or local inundations might fully account for such other phenomena as have suggested the above violent hypothesis. But even were this devastating rush of waters from one pole to the other fully established, we cannot think the explanation of the phenomenon here proposed at all adequate. It is a theory elaborated by M. Adheinar, which has, we think, been already presented in a popular form in All the Year Round. The theory rests upon the observed gyratory motion of the earth in its revolution round the sun. If the axis of rotation of the earth remained always parallel to itself in the line of its orbit, the moments of the two equinoxes would always be constant, viz., when the earth's centre coincided with particular points on the line of the orbit or ecliptic, in fact, with the extremities of the minor axis passing through the centre of the sun, then this line would be exactly perpendicular to the earth's axes of rotation ; exactly one hemisphere from pole to pole would be illumined by the sun's light, and perfect equality of day and night would prevail everywhere on its surface. But as in fact the earth spins like a top, the axis of rotation does not always remain parallel to itself and at the fixed points, the line from the sun's centre to the earth's is not exactly perpendicular to the axes of the earth's rotation. Each spin takes eighteen revolutions round the sun to complete itself in. Still the yearly difference, owing to the gyration, is appreciable, and the equinoctial points are year after year receding towards the east. This is the "precession of the equinoxes," observed some 2,000 years ago by Hipparchus, the gyratory motion itself being attributed to the "action of the sun and moon on the equatorial bulging of our planet." One incident of this gyration is that the South Pole is at present removed more away from the sun and the North Pole inclined further towards it. "Our summer is longer and our winter shorter than the summer and winter in our antipodes," but "in 10,500 years the present oonditions will be reversed ; the terrestrial axis, and consequently the poles will have accomplished half of their bi-conical evolutions round the globe's centre; the summer solstice of our hemisphere, which is now still near to the aphelion, will coincide, on the contrary, with the perihelion, while the winter solstice will correspond to the aphelion. It will then be the northern hemisphere whose summer will be shorter and its winter longer, and reciprocally the austral hemisphere will have longer summers and shorter winters." The gist of this is that the constant ref rig ration to which the South Pole is now subjected leads to an abnormal accumulation of ice sufficient to alter sensibly the position of the earth's centre of gravity in that direction, the waters of the sea, attracted by this mass of matter, and following the earth's centre of gravity, are borne to this pole, covering the southern hemisphere, and leaving the northern uncovered. When, however, "the great summer" at the South Pole begins, the process will be reversed. The ice will melt at the South and accumulate at the North Pole, the centre of gravity will repass towards that point, and "the devastating rush of waters," alluded to above, will submerge the northern continents. Startling as this prospect is, it certainly sloes not carry with it much conviction of its truth. Even supposing the precession of the equinoxes to be due to the cause stated, and that no mathematical or astronomical considerations can be urged against it, it seems most unlikely that the mechanical effects should be such as are here represented. The first position of the centre of gravity must prevent the ice from accumulating; but if it were to double the extent of the present antarctic continent, the change in the centre of gravity would be insignificant, and the attraction of the water owing to this change, or the attraction to the ice itself, inconsiderable. But even supposing the result to be of the dimensions here imagined, how could its reversal have the effect described? The melting of the ice would then be so gradual as to be hardly noticeable. One might as well suppose a rush of water from one pole on the commencement of the great winter at the other, as a rush back at the commencement of the great summer. It is, in fact, unworthy of consideration. M. Alangin cannot be said to espouse or more than favour the theory, but even that is to be wondered at, and in a book of this kind not to be excused. We think the translator might easily have confined its scope to the simple and established miracles of nature.
The second book considers the "Phenomena of the Ocean," of which the tides and currents are most interestingly treated. A chart of ocean currents shows at a glance how considerably they have influenced the formation and outline of the continents, and how the position of mountain ranges has influenced them.
Both together seem almost sufficient to explain the existing arrangement of land and water. Under this head is also considered the atmospheric circulation and perturbations, in so far as they are related to the movements of the ocean.
Book the third furnishes a sketch of the various diri. sions of the animal kingdom which inhabit the marine weal We have here to take exception to a hypothesis which M. Mallon introduces with great favour, but which is below discussion, "that the vegetable tissues might be nothing more than the defensive envelope of an animated body labouring at the formation of the various parts of the plants." He remarks very truly, "Could this theory be confirmed, it would induce in science a complete revolution, by effacing the demarcation hitherto admitted between the animal and vegetable kingdoms, and by giving a startling consecration to the idea so long purely hypothetical of a perfect unity of plan throughout creation." The "world-making iufusoria" which, extracting lime for their shells from thersea-water, accumulate the various cretaceous strata, so prolific that one million are born in ten days of a single individual ; the zoophytes, which build up their great common lodging-houses or coral reefs even to a length of 1,300 miles ; sponges, actinine, molluscs, polypi, crustacea, fishes, cetacea, thalassite.s, phocse, and, finally, the birds of the ocean are separately and amusingly treated, as also the fossil remains of the ancient seas. The illustrations of this book are extremely finished and artistic. M. Mangin discusses the problem of the Sea Serpent, and is convinced by a Mr. Smith's story that it is nothing but a long piece of seaweed. We are inclined to consider Mr. Smith not more trustworthy than the witnesses on the other side. That a stray plesiosaurus dolichodeirus should still exist in the Atlantic is at least possible, but we have never before heard of an alga of such dimensions and appearance.
The fourth and last book, entitled "Man and the 0 ceau,".descrilies the incidents and past history of the various fisheries ; whale. hunting, and the feuds of the English and Dutch whalers ; diving, and seal-hunting, which seems to be as imprudently conducted as whale-hunting was before it, and to be threatened with a like untimely end. "The pursuit of the Polar seals is carried on vith so little economy or discernment, that its extinction is only a question of time. In a single voyage, says M. Hauteville, the English fisheries have killed upwards of 25,000 seals ; in 1858 the Norwegians, at Spitzbergen, caught 54,000. It is evident that the species, numerous as it is, cannot long withstand such wholesale butcheries, and that the chase of which it is the object must soon terminate like that of the whale, in the disappearance of the game, if civilized nations do not decide upon adopting in concert energetic measures to confine it within reasonable limits."