Chapter X: Part 10
Now, the fact as to the comparative size of our own cetaceans and of 'geological' animals is just this. The Atlantosaurus of the Western American Jurassic beds, a great erect lizard, is the very largest creature ever known to have inhabited this sublunary sphere. His entire length is supposed to have reached about a hundred feet (for no complete skeleton has ever been discovered), while in stature he appears to have stood some thirty feet high, or over. In any case, he was undoubtedly a very big animal indeed, for his thigh-bone alone measures eight feet, or two feet taller than that glory of contemporary civilisation, a British Grenadier. This, of course, implies a very decent total of height and size; but our own sperm whale frequently attains a good length of seventy feet, while the rorquals often run up to eighty, ninety, and even a hundred feet. We are thus fairly entitled to say that we have at least one species of animal now living which, occasionally at any rate, equals in size the very biggest and most colossal form known inferentially to geological science. Indeed when we consider the extraordinary compactness and rotundity of the modern cetaceans, as compared with the tall limbs and straggling skeleton of the huge Jurassic deinosaurs, I am inclined to believe that the tonnage of a decent modern rorqual must positively exceed that of the gigantic Atlantosaurus, the great lizard of the west, _in propria persona_. I doubt, in short, whether even the solid thigh-bone of the deinosaur could ever have supported the prodigious weight of a full-grown family razor-back whale. The mental picture of these unwieldy monsters hopping casually about, like Alice's Gryphon in Tenniel's famous sketch, or like that still more parlous brute, the chortling Jabberwock, must be left to the vivid imagination of the courteous reader, who may fill in the details for himself as well as he is able.
If we turn from the particular comparison of selected specimens (always an unfair method of judging) to the general aspect of our contemporary fauna, I venture confidently to claim for our own existing human period as fine a collection of big animals as any other ever exhibited on this planet by any one single rival epoch. Of course, if you are going to lump all the extinct monsters and horrors into one imaginary unified fauna, regardless of anachronisms, I have nothing more to say to you; I will candidly admit that there were more great men in all previous generations put together, from Homer to Dickens, from Agamemnon to Wellington, than there are now existing in this last quarter of our really very respectable nineteenth century. But if you compare honestly age with age, one at a time, I fearlessly maintain that, so far from there being any falling off in the average bigness of things generally in these latter days, there are more big things now living than there ever were in any one single epoch, even of much longer duration than the 'recent' period.
I suppose we may fairly say, from the evidence before us, that there have been two Augustan Ages of big animals in the history of our earth--the Jurassic period, which was the zenith of the reptilian type, and the Pliocene, which was the zenith of the colossal terrestrial tertiary mammals. I say on purpose, 'from the evidence before us,' because, as I shall go on to explain hereafter, I do not myself believe that any one age has much surpassed another in the general size of its fauna, since the Permian Epoch at least; and where we do not get geological evidence of the existence of big animals in any particular deposit, we may take it for granted, I think, that that deposit was laid down under conditions unfavourable to the preservation of the remains of large species. For example, the sediment now being accumulated at the bottom of the Caspian cannot possibly contain the bones of any creature much larger than the Caspian seal, because there are no big species there swimming; and yet that fact does not negative the existence in other places of whales, elephants, giraffes, buffaloes, and hippopotami. Nevertheless, we can only go upon the facts before us; and if we compare our existing fauna with the fauna of Jurassic and Pliocene times, we shall at any rate be putting it to the test of the severest competition that lies within our power under the actual circumstances.
In the Jurassic age there were undoubtedly a great many very big reptiles. 'A monstrous eft was of old the lord and master of earth: For him did his high sun flame and his river billowing ran: And he felt himself in his pride to be nature's crowning race.' There was the ichthyosaurus, a fish-like marine lizard, familiar to us all from a thousand reconstructions, with his long thin body, his strong flippers, his stumpy neck, and his huge pair of staring goggle eyes. The ichthyosaurus was certainly a most unpleasant creature to meet alone in a narrow strait on a dark night; but if it comes to actual measurement, the very biggest ichthyosaurian skeleton ever unearthed does not exceed twenty-five feet from snout to tail. Now, this is an extremely decent size for a reptile, as reptiles go; for the crocodile and alligator, the two biggest existing lizards, seldom attain an extreme length of sixteen feet. But there are other reptiles now living that easily beat the ichthyosaurus, such, for example, as the larger pythons or rock-snakes, which not infrequently reach to thirty feet, and measure round the waist as much as a London alderman of the noblest proportions. Of course, other Jurassic saurians easily beat this simple record. Our British Megalosaurus only extended twenty-five feet in length, and carried weight not exceeding three tons; but, his rival Ceteosaurus stood ten feet high, and measured fifty feet from the tip of his snout to the end of his tail; while the dimensions of Titanosaurus may be briefly described as sixty feet by thirty, and those of Atlantosaurus as one hundred by thirty-two. Viewed as reptiles, we have certainly nothing at all to come up to these; but our cetaceans, as a group, show an assemblage of species which could very favourably compete with the whole lot of Jurassic saurians at any cattle show. Indeed, if it came to tonnage, I believe a good blubbery right-whale could easily give points to any deinosaur that ever moved upon oolitic continents.
The great mammals of the Pliocene age, again, such as the deinotherium and the mastodon, were also, in their way, very big things in livestock; but they scarcely exceeded the modern elephant, and by no means came near the modern whales. A few colossal ruminants of the same period could have held their own well against our existing giraffes, elks, and buffaloes; but, taking the group as a group, I don't think there is any reason to believe that it beat in general aspect the living fauna of this present age.
For few people ever really remember how very many big animals we still possess. We have the Indian and the African elephant, the hippopotamus, the various rhinoceroses, the walrus, the giraffe, the elk, the bison, the musk ox, the dromedary, and the camel. Big marine animals are generally in all ages bigger than their biggest terrestrial rivals, and most people lump all our big existing cetaceans under the common and ridiculous title of whales, which makes this vast and varied assortment of gigantic species seem all reducible to a common form. As a matter of fact, however, there are several dozen colossal marine animals now sporting and spouting in all oceans, as distinct from one another as the camel is from the ox, or the elephant from the hippopotamus. Our New Zealand Berardius easily beats the ichthyosaurus; our sperm whale is more than a match for any Jurassic European deinosaur; our rorqual, one hundred feet long, just equals the dimensions of the gigantic American Atlantosaurus himself. Besides these exceptional monsters, our bottleheads reach to forty feet, our California whales to forty-four, our hump-backs to fifty, and our razor-backs to sixty or seventy. True fish generally fall far short of these enormous dimensions, but some of the larger sharks attain almost equal size with the biggest cetaceans. The common blue shark, with his twenty-five feet of solid rapacity, would have proved a tough antagonist, I venture to believe, for the best bred enaliosaurian that ever munched a lias ammonite. I would back our modern carcharodon, who grows to forty feet, against any plesiosaurus that ever swam the Jurassic sea. As for rhinodon, a gigantic shark of the Indian Ocean, he has been actually measured to a length of fifty feet, and is stated often to attain seventy. I will stake my reputation upon it that he would have cleared the secondary seas of their great saurians in less than a century. When we come to add to these enormous marine and terrestrial creatures such other examples as the great snakes, the gigantic cuttle-fish, the grampuses, and manatees, and sea-lions, and sunfish, I am quite prepared fearlessly to challenge any other age that ever existed to enter the lists against our own for colossal forms of animal life.
Again, it is a point worth noting that a great many of the very big animals which people have in their minds when they talk vaguely about everything having been so very much bigger 'in those days' have become extinct within a very late period, and are often, from the geological point of view, quite recent.
For example, there is our friend the mammoth. I suppose no animal is more frequently present to the mind of the non-geological speaker, when he talks indefinitely about the great extinct monsters, than the familiar figure of that huge-tusked, hairy northern elephant. Yet the mammoth, chronologically speaking, is but a thing of yesterday. He was hunted here in England by men whose descendants are probably still living--at least so Professor Boyd Dawkins solemnly assures us; while in Siberia his frozen body, flesh and all, is found so very fresh that the wolves devour it, without raising any unnecessary question as to its fitness for lupine food. The Glacial Epoch is the yesterday of geological time, and it was the Glacial Epoch that finally killed off the last mammoth. Then, again, there is his neighbour, the mastodon. That big tertiary proboscidean did not live quite long enough, it is true, to be hunted by the cavemen of the Pleistocene age, but he survived at any rate as long as the Pliocene--our day before yesterday--and he often fell very likely before the fire-split flint weapons of the Abbé Bourgeois' Miocene men. The period that separates him from our own day is as nothing compared with the vast and immeasurable interval that separates him from the huge marine saurians of the Jurassic world. To compare the relative lapses of time with human chronology, the mastodon stands to our own fauna as Beau Brummel stands to the modern masher, while the saurians stand to it as the Egyptian and Assyrian warriors stand to Lord Wolseley and the followers of the Mahdi.
Once more, take the gigantic moa of New Zealand, that enormous bird who was to the ostrich as the giraffe is to the antelope; a monstrous emu, as far surpassing the ostriches of to-day as the ostriches surpass all the other fowls of the air. Yet the moa, though now extinct, is in the strictest sense quite modern, a contemporary very likely of Queen Elizabeth or Queen Anne, exterminated by the Maoris only a very little time before the first white settlements in the great southern archipelago. It is even doubtful whether the moa did not live down to the days of the earliest colonists, for remains of Maori encampments are still discovered, with the ashes of the fireplace even now unscattered, and the close-gnawed bones of the gigantic bird lying in the very spot where the natives left them after their destructive feasts. So, too, with the big sharks. Our modern carcharodon, who runs (as I have before noted) to forty feet in length, is a very respectable monster indeed, as times go; and his huge snapping teeth, which measure nearly two inches long by one and a half broad, would disdain to make two bites of the able-bodied British seaman. But the naturalists of the 'Challenger' expedition dredged up in numbers from the ooze of the Pacific similar teeth, five inches long by four wide, so that the sharks to which they originally belonged must, by parity of reasoning, have measured nearly a hundred feet in length. This, no doubt, beats our biggest existing shark, the rhinodon, by some thirty feet. Still, the ooze of the Pacific is a quite recent or almost modern deposit, which is even now being accumulated on the sea bottom, and there would be really nothing astonishing in the discovery that some representatives of these colossal carcharodons are to this day swimming about at their lordly leisure among the coral reefs of the South Sea Islands. That very cautious naturalist, Dr. Günther, of the British Museum, contents himself indeed by merely saying: 'As we have no record of living individuals of that bulk having been observed, the gigantic species to which these teeth belonged must probably have become extinct within a comparatively recent period.'
If these things are so, the question naturally suggests itself: Why should certain types of animals have attained their greatest size at certain different epochs, and been replaced at others by equally big animals of wholly unlike sorts? The answer, I believe, is simply this: Because there is not room and food in the world at any one time for more than a certain relatively small number of gigantic species. Each great group of animals has had successively its rise, its zenith, its decadence, and its dotage; each at the period of its highest development has produced a considerable number of colossal forms; each has been supplanted in due time by higher groups of totally different structure, which have killed off their predecessors, not indeed by actual stress of battle, but by irresistible competition for food and prey. The great saurians were thus succeeded by the great mammals, just as the great mammals are themselves in turn being ousted, from the land at least, by the human species.
Let us look briefly at the succession of big animals in the world, so far as we can follow it from the mutilated and fragmentary record of the geological remains.
The very earliest existing fossils would lead us to believe what is otherwise quite probable, that life on our planet began with very small forms--that it passed at first through a baby stage. The animals of the Cambrian period are almost all small mollusks, star-fishes, sponges, and other simple, primitive types of life. There were as yet no vertebrates of any sort, not even fishes, far less amphibians, reptiles, birds, or mammals. The veritable giants of the Cambrian world were the crustaceans, and especially the trilobites, which, nevertheless, hardly exceeded in size a good big modern lobster. The biggest trilobite is some two feet long; and though we cannot by any means say that this was really the largest form of animal life then existing, owing to the extremely broken nature of the geological record, we have at least no evidence that anything bigger as yet moved upon the face of the waters. The trilobites, which were a sort of triple-tailed crabs (to speak very popularly), began in the Cambrian Epoch, attained their culminating point in the Silurian, waned in the Devonian, and died out utterly in the Carboniferous seas.
It is in the second great epoch, the Silurian, that the cuttle-fish tribe, still fairly represented by the nautilus, the argonaut, the squid, and the octopus, first began to make their appearance upon this or any other stage. The cuttle-fishes are among the most developed of invertebrate animals; they are rapid swimmers; they have large and powerful eyes; and they can easily enfold their prey (_teste_ Victor Hugo) in their long and slimy sucker-clad arms. With these natural advantages to back them up, it is not surprising that the cuttle family rapidly made their mark in the world. They were by far the most advanced thinkers and actors of their own age, and they rose almost at once to be the dominant creatures of the primæval ocean in which they swam. There were as yet no saurians or whales to dispute the dominion with these rapacious cephalopods, and so the cuttle family had things for the time all their own way. Before the end of the Silurian Epoch, according to that accurate census-taker, M. Barrande, they had blossomed forth into no less than 1,622 distinct species. For a single family to develop so enormous a variety of separate forms, all presumably derived from a single common ancestor, argues, of course, an immense success in life; and it also argues a vast lapse of time during which the different species were gradually demarcated from one another.
Some of the ammonites, which belonged to this cuttle-fish group, soon attained a very considerable size; but a shell known as the orthoceras (I wish my subject didn't compel me to use such _very_ long words, but I am not personally answerable, thank heaven, for the vagaries of modern scientific nomenclature) grew to a bigger size than that of any other fossil mollusk, sometimes measuring as much as six feet in total length. At what date the gigantic cuttles of the present day first began to make their appearance it would be hard to say, for their shell-less bodies are so soft that they could leave hardly anything behind in a fossil state; but the largest known cuttle, measured by Mr. Gabriel, of Newfoundland, was eighty feet in length, including the long arms.
These cuttles are the only invertebrates at all in the running so far as colossal size is concerned, and it will be observed that here the largest modern specimen immeasurably beats the largest fossil form of the same type. I do not say that there were not fossil forms quite as big as the gigantic calamaries of our own time--on the contrary, I believe there were; but if we go by the record alone we must confess that, in the matter of invertebrates at least, the balance of size is all in favour of our own period.
The vertebrates first make their appearance, in the shape of fishes, towards the close of the Silurian period, the second of the great geological epochs. The earliest fish appear to have been small, elongated, eel-like creatures, closely resembling the lampreys in structure; but they rapidly developed in size and variety, and soon became the ruling race in the waters of the ocean, where they maintained their supremacy till the rise of the great secondary saurians. Even then, in spite of the severe competition thus introduced, and still later, in spite of the struggle for life against the huge modern cetaceans (the true monarchs of the recent seas), the sharks continued to hold their own as producers of gigantic forms; and at the present day their largest types probably rank second only to the whales in the whole range of animated nature. There seems no reason to doubt that modern fish, as a whole, quite equal in size the piscine fauna of any previous geological age.
It is somewhat different with the next great vertebrate group, the amphibians, represented in our own world only by the frogs, the toads, the newts, and the axolotls. Here we must certainly with shame confess that the amphibians of old greatly surpassed their degenerate descendants in our modern waters. The Japanese salamander, by far the biggest among our existing newts, never exceeds a yard in length from snout to tail; whereas some of the labyrinthodonts (forgive me once more) of the Carboniferous Epoch must have reached at least seven or eight feet from stem to stern. But the reason of this falling off is not far to seek. When the adventurous newts and frogs of that remote period first dropped their gills and hopped about inquiringly on the dry land, under the shadow of the ancient tree-ferns and club-mosses, they were the only terrestrial vertebrates then existing, and they had the field (or, rather, the forest) all to themselves. For a while, therefore, like all dominant races for the time being, they blossomed forth at their ease into relatively gigantic forms. Frogs as big as donkeys, and efts as long as crocodiles, luxuriated to their hearts' content in the marshy lowlands, and lorded it freely over the small creatures which they found in undisturbed possession of the Carboniferous isles. But as ages passed away, and new improvements were slowly invented and patented by survival of the fittest in the offices of nature, their own more advanced and developed descendants, the reptiles and mammals, got the upper hand with them, and soon lived them down in the struggle for life, so that this essentially intermediate form is now almost entirely restricted to its one adapted seat, the pools and ditches that dry up in summer.
The reptiles, again, are a class in which the biggest modern forms are simply nowhere beside the gigantic extinct species. First appearing on the earth at the very close of the vast primary periods--in the Permian age--they attained in secondary times the most colossal proportions, and have certainly never since been exceeded in size by any later forms of life in whatever direction. But one must remember that during the heyday of the great saurians, there were as yet no birds and no mammals. The place now filled in the ocean by the whales and grampuses, as well as the place now filled in the great continents by the elephants, the rhinoceroses, the hippopotami, and the other big quadrupeds, was then filled exclusively by huge reptiles, of the sort rendered familiar to us all by the restored effigies on the little island in the Crystal Palace grounds. Every dog has his day, and the reptiles had _their_ day in the secondary period. The forms into which they developed were certainly every whit as large as any ever seen on the surface of this planet, but not, as I have already shown, appreciably larger than those of the biggest cetaceans known to science in our own time.
During the very period, however, when enaliosaurians and pterodactyls were playing such pranks before high heaven as might have made contemporary angels weep, if they took any notice of saurian morality, a small race of unobserved little prowlers was growing up in the dense shades of the neighbouring forests which was destined at last to oust the huge reptiles from their empire over earth, and to become in the fulness of time the exclusively dominant type of the whole planet. In the trias we get the first remains of mammalian life in the shape of tiny rat-like animals, marsupial in type, and closely related to the banded ant-eaters of New South Wales at the present day. Throughout the long lapse of the secondary ages, across the lias, the oolite, the wealden, and the chalk, we find the mammalian race slowly developing into opossums and kangaroos, such as still inhabit the isolated and antiquated continent of Australia. Gathering strength all the time for the coming contest, increasing constantly in size of brain and keenness of intelligence, the true mammals were able at last, towards the close of the secondary ages, to enter the lists boldly against the gigantic saurians. With the dawn of the tertiary period, the reign of the reptiles begins to wane, and the reign of the mammals to set in at last in real earnest. In place of the ichthyosaurs we get the huge cetaceans; in place of the deinosaurs we get the mammoth and the mastodon; in place of the dominant reptile groups we get the first precursors of man himself.
The history of the great birds has been somewhat more singular. Unlike the other main vertebrate classes, the birds (as if on purpose to contradict the proverb) seem never yet to have had their day. Unfortunately for them, or at least for their chance of producing colossal species, their evolution went on side by side, apparently, with that of the still more intelligent and more powerful mammals; so that, wherever the mammalian type had once firmly established itself, the birds were compelled to limit their aspirations to a very modest and humble standard. Terrestrial mammals, however, cannot cross the sea; so in isolated regions, such as New Zealand and Madagascar, the birds had things all their own way. In New Zealand, there are no indigenous quadrupeds at all; and there the huge moa attained to dimensions almost equalling those of the giraffe. In Madagascar, the mammalian life was small and of low grade, so the gigantic æpyornis became the very biggest of all known birds. At the same time, these big species acquired their immense size at the cost of the distinctive birdlike habit of flight. A flying moa is almost an impossible conception; even the ostriches compete practically with the zebras and antelopes rather than with the eagles, the condors, or the albatrosses. In like manner, when a pigeon found its way to Mauritius, it developed into the practically wingless dodo; while in the northern penguins, on their icy perches, the fore limbs have been gradually modified into swimming organs, exactly analogous to the flippers of the seal.
Are the great animals now passing away and leaving no representatives of their greatness to future ages? On land at least that is very probable. Man, diminutive man, who, if he walked on all fours, would be no bigger than a silly sheep, and who only partially disguises his native smallness by his acquired habit of walking erect on what ought to be his hind legs--man has upset the whole balanced economy of nature, and is everywhere expelling and exterminating before him the great herbivores, his predecessors. He needs for his corn and his bananas the fruitful plains which were once laid down in prairie or scrubwood. Hence it seems not unlikely that the elephant, the hippopotamus, the rhinoceros, and the buffalo must go. But we are still a long way off from that final consummation, even on dry land; while as for the water, it appears highly probable that there are as good fish still in the sea as ever came out of it. Whether man himself, now become the sole dominant animal of our poor old planet, will ever develop into Titanic proportions, seems far more problematical. The race is now no longer to the swift, nor the battle to the strong. Brain counts for more than muscle, and mind has gained the final victory over mere matter. Goliath of Gath has shrunk into insignificance before the Gatling gun; as in the fairy tales of old, it is cunning little Jack with his clever devices who wins the day against the heavy, clumsy, muddle-headed giants. Nowadays it is our 'Minotaurs' and 'Warriors' that are the real leviathans and behemoths of the great deep; our Krupps and Armstrongs are the fire-breathing krakens of the latter-day seas. Instead of developing individually into huge proportions, the human race tends rather to aggregate into vast empires, which compete with one another by means of huge armaments, and invent mitrailleuses and torpedos of incredible ferocity for their mutual destruction. The dragons of the prime that tare each other in their slime have yielded place to eighty-ton guns and armour-plated turret-ships. Those are the genuine lineal representatives on our modern seas of the secondary saurians. Let us hope that some coming geologist of the dim future, finding the fossil remains of the sunken 'Captain,' or the plated scales of the 'Comte de Grasse,' firmly embedded in the upheaved ooze of the existing Atlantic, may shake his head in solemn deprecation at the horrid sight, and thank heaven that such hideous carnivorous creatures no longer exist in his own day.
FOSSIL FOOD
There is something at first sight rather ridiculous in the idea of eating a fossil. To be sure, when the frozen mammoths of Siberia were first discovered, though they had been dead for at least 80,000 years (according to Dr. Croll's minimum reckoning for the end of the great ice age), and might therefore naturally have begun to get a little musty, they had nevertheless been kept so fresh, like a sort of prehistoric Australian mutton, in their vast natural refrigerators, that the wolves and bears greedily devoured the precious relics for which the naturalists of Europe would have been ready gladly to pay the highest market price of best beefsteak. Those carnivorous vandals gnawed off the skin and flesh with the utmost appreciation, and left nothing but the tusks and bones to adorn the galleries of the new Natural History Museum at South Kensington. But then wolves and bears, especially in Siberia, are not exactly fastidious about the nature of their meat diet. Furthermore, some of the bones of extinct animals found beneath the stalagmitic floor of caves, in England and elsewhere, presumably of about the same age as the Siberian mammoths, still contain enough animal matter to produce a good strong stock for antediluvian broth, which has been scientifically described by a high authority as pre-Adamite jelly. The congress of naturalists at Tübingen a few years since had a smoking tureen of this cave-bone soup placed upon the dinner-table at their hotel one evening, and pronounced it with geological enthusiasm 'scarcely inferior to prime ox-tail.' But men of science, too, are accustomed to trying unsavoury experiments, which would go sadly against the grain with less philosophic and more squeamish palates. They think nothing of tasting a caterpillar that birds will not touch, in order to discover whether it owes its immunity from attack to some nauseous, bitter, or pungent flavouring; and they even advise you calmly to discriminate between two closely similar species of snails by trying which of them when chewed has a delicate _soupçon_ of oniony aroma. So that naturalists in this matter, as the children say, don't count: their universal thirst for knowledge will prompt them to drink anything, down even to _consommé_ of quaternary cave-bear.
There is one form of fossil food, however, which appears constantly upon all our tables at breakfast, lunch, and dinner, every day, and which is so perfectly familiar to every one of us that we almost forget entirely its immensely remote geological origin. The salt in our salt-cellars is a fossil product, laid down ages ago in some primæval Dead Sea or Caspian, and derived in all probability (through the medium of the grocer) from the triassic rocks of Cheshire or Worcestershire. Since that thick bed of rock-salt was first precipitated upon the dry floor of some old evaporated inland sea, the greater part of the geological history known to the world at large has slowly unrolled itself through incalculable ages. The dragons of the prime have begun and finished their long (and Lord Tennyson says slimy) race. The fish-like saurians and flying pterodactyls of the secondary period have come into existence and gone out of it gracefully again. The whole family of birds has been developed and diversified into its modern variety of eagles and titmice. The beasts of the field have passed through sundry stages of mammoth and mastodon, of sabre-toothed lion and huge rhinoceros. Man himself has progressed gradually from the humble condition of a 'hairy arboreal quadruped'--these bad words are Mr. Darwin's own--to the glorious elevation of an erect, two-handed creature, with a county suffrage question and an intelligent interest in the latest proceedings of the central divorce court. And after all those manifold changes, compared to which the entire period of English history, from the landing of Julius Cæsar to the appearance of this present volume (to take two important landmarks), is as one hour to a human lifetime, we quietly dig up the salt to-day from that dry lake bottom and proceed to eat it with the eggs laid by the hens this morning for this morning's breakfast, just as though the one food-stuff were not a whit more ancient or more dignified in nature than the other. Why, mammoth steak is really quite modern and commonplace by the side of the salt in the salt-cellar that we treat so cavalierly every day of our ephemeral existence.
The way salt got originally deposited in these great rock beds is very well illustrated for us by the way it is still being deposited in the evaporating waters of many inland seas. Every schoolboy knows of course (though some persons who are no longer schoolboys may just possibly have forgotten) that the Caspian is in reality only a little bit of the Mediterranean, which has been cut off from the main sea by the gradual elevation of the country between them. For many ages the intermediate soil has been quite literally rising in the world; but to this day a continuous chain of salt lakes and marshes runs between the Caspian and the Black Sea, and does its best to keep alive the memory of the time when they were both united in a single basin. All along this intervening tract, once sea but now dry land, banks of shells belonging to kinds still living in the Caspian and the Black Sea alike testify to the old line of water communication. One fine morning (date unknown) the intermediate belt began to rise up between them; the water was all pushed off into the Caspian, but the shells remained to tell the tale even unto this day.
Now, when a bit of the sea gets cut off in this way from the main ocean, evaporation of its waters generally takes place rather faster than the return supply of rain by rivers and lesser tributaries. In other words, the inland sea or salt lake begins slowly to dry up. This is now just happening in the Caspian, which is in fact a big pool in course of being slowly evaporated. By-and-by a point is reached when the water can no longer hold in solution the amount of salts of various sorts that it originally contained. In the technical language of chemists and physicists it begins to get supersaturated. Then the salts are thrown down as a sediment at the bottom of the sea or lake, exactly as crust formed on the bottom of a kettle. Gypsum is the first material to be so thrown down, because it is less soluble than common salt, and therefore sooner got rid of. It forms a thick bottom layer in the bed of all evaporating inland seas; and as plaster of Paris it not only gives rise finally to artistic monstrosities hawked about the streets for the degradation of national taste, but also plays an important part in the manufacture of bonbons, the destruction of the human digestion, and the ultimate ruin of the dominant white European race. Only about a third of the water in a salt lake need be evaporated before the gypsum begins to be deposited in a solid layer over its whole bed; it is not till 93 per cent. of the water has gone, and only 7 per cent. is left, that common salt begins to be thrown down. When that point of intensity is reached, the salt, too, falls as a sediment to the bottom, and there overlies the gypsum deposit. Hence all the world over, wherever we come upon a bed of rock salt, it almost invariably lies upon a floor of solid gypsum.
The Caspian, being still a very respectable modern sea, constantly supplied with fresh water from the surrounding rivers, has not yet begun by any means to deposit salt on its bottom from its whole mass; but the shallow pools and long bays around its edge have crusts of beautiful rose-coloured salt-crystals forming upon their sides; and as these lesser basins gradually dry up, the sand, blown before the wind, slowly drifts over them, so as to form miniature rock-salt beds on a very small scale. Nevertheless, the young and vigorous Caspian only represents the first stage in the process of evaporation of an inland sea. It is still fresh enough to form the abode of fish and mollusks; and the irrepressible young lady of the present generation is perhaps even aware that it contains numbers of seals, being in fact the seat of one of the most important and valuable seal-fisheries in the whole world. It may be regarded as a typical example of a yet youthful and lively inland sea.
The Dead Sea, on the other hand, is an old and decrepit salt lake in a very advanced state of evaporation. It lies several feet below the level of the Mediterranean, just as the Caspian lies several feet below the level of the Black Sea; and as in both cases the surface must once have been continuous, it is clear that the water of either sheet must have dried up to a very considerable extent. But, while the Caspian has shrunk only to 85 feet below the Black Sea, the Dead Sea has shrunk to the enormous depth of 1,292 feet below the Mediterranean. Every now and then, some enterprising De Lesseps or other proposes to dig a canal from the Mediterranean to the Dead Sea, and so re-establish the old high level. The effect of this very revolutionary proceeding would be to flood the entire Jordan Valley, connect the Sea of Galilee with the Dead Sea, and play the dickens generally with Scripture geography, to the infinite delight of Sunday school classes. Now, when the Dead Sea first began its independent career as a separate sheet of water on its own account, it no doubt occupied the whole bed of this imaginary engineers' lake--spreading, if not from Dan to Beersheba, at any rate from Dan to Edom, or, in other words, along the whole Jordan Valley from the Sea of Galilee and even the Waters of Merom to the southern desert. (I will not insult the reader's intelligence and orthodoxy by suggesting that perhaps he may not be precisely certain as to the exact position of the Waters of Merom; but I will merely recommend him just to refresh his memory by turning to his atlas, as this is an opportunity which may not again occur.) The modern Dead Sea is the last shrunken relic of such a considerable ancient lake. Its waters are now so very concentrated and so very nasty that no fish or other self-respecting animal can consent to live in them; and so buoyant that a man can't drown himself, even if he tries, because the sea is saturated with salts of various sorts till it has become a kind of soup or porridge, in which a swimmer floats, will he nill he. Persons in the neighbourhood who wish to commit suicide are therefore obliged to go elsewhere: much as in Tasmania, the healthiest climate in the world, people who want to die are obliged to run across for a week to Sydney or Melbourne.
The waters of the Dead Sea are thus in the condition of having already deposited almost all their gypsum, as well as the greater part of the salt they originally contained. They are, in fact, much like sea water which has been boiled down till it has reached the state of a thick salty liquid; and though most of the salt is now already deposited in a deep layer on the bottom, enough still remains in solution to make the Dead Sea infinitely salter than the general ocean. At the same time, there are a good many other things in solution in sea water besides gypsum and common salt; such as chloride of magnesia sulphate of potassium, and other interesting substances with pretty chemical names, well calculated to endear them at first sight to the sentimental affections of the general public. These other by-contents of the water are often still longer in getting deposited than common salt; and, owing to their intermixture in a very concentrated form with the mother liquid of the Dead Sea, the water of that evaporating lake is not only salt but also slimy and fetid to the last degree, its taste being accurately described as half brine, half rancid oil. Indeed, the salt has been so far precipitated already that there is now five times as much chloride of magnesium left in the water as there is common salt. By the way, it is a lucky thing for us that these various soluble minerals are of such constitution as to be thrown down separately at different stages of concentration in the evaporating liquid; for, if it were otherwise, they would all get deposited together, and we should find on all old salt lake beds only a mixed layer of gypsum, salt, and other chlorides and sulphates, absolutely useless for any practical human purpose. In that case, we should be entirely dependent upon marine salt pans and artificial processes for our entire salt supply. As it is, we find the materials deposited one above another in regular layers; first, the gypsum at the bottom; then the rock-salt; and last of all, on top, the more soluble mineral constituents.
The Great Salt Lake of Utah, sacred to the memory of Brigham Young, gives us an example of a modern saline sheet of very different origin, since it is in fact not a branch of the sea at all, but a mere shrunken remnant of a very large fresh-water lake system, like that of the still-existing St. Lawrence chain. Once upon a time, American geologists say, a huge sheet of water, for which they have even invented a definite name, Lake Bonneville, occupied a far larger valley among the outliers of the Rocky Mountains, measuring 300 miles in one direction by 180 miles in the other. Beside this primitive Superior lay a second great sheet--an early Huron--(Lake Lahontan, the geologists call it) almost as big, and equally of fresh water. By-and-by--the precise dates are necessarily indefinite--some change in the rainfall, unregistered by any contemporary 'New York Herald,' made the waters of these big lakes shrink and evaporate. Lake Lahontan shrank away like Alice in Wonderland, till there was absolutely nothing left of it; Lake Bonneville shrank till it attained the diminished size of the existing Great Salt Lake. Terrace after terrace, running in long parallel lines on the sides of the Wahsatch Mountains around, mark the various levels at which it rested for awhile on its gradual downward course. It is still falling indeed; and the plain around is being gradually uncovered, forming the white salt-encrusted shore with which all visitors to the Mormon city are so familiar.
But why should the water have become briny? Why should the evaporation of an old Superior produce at last a Great Salt Lake? Well, there is a small quantity of salt in solution even in the freshest of lakes and ponds, brought down to them by the streams or rivers; and, as the water of the hypothetical Lake Bonneville slowly evaporated, the salt and other mineral constituents remained behind. Thus the solution grew constantly more and more concentrated, till at the present day it is extremely saline. Professor Geikie (to whose works the present paper is much indebted) found that he floated on the water in spite of himself; and the under sides of the steps at the bathing-places are all encrusted with short stalactites of salt, produced from the drip of the bathers as they leave the water. The mineral constituents, however, differ considerably in their proportions from those found in true salt lakes of marine origin; and the point at which the salt is thrown down is still far from having been reached. Great Salt Lake must simmer in the sun for many centuries yet before the point arrives at which (as cooks say) it begins to settle.
That is the way in which deposits of salt are being now produced on the world's surface, in preparation for that man of the future who, as we learn from a duly constituted authority, is to be hairless, toothless, web-footed, and far too respectable ever to be funny. Man of the present derives his existing salt-supply chiefly from beds of rock-salt similarly laid down against his expected appearance some hundred thousand æons or so ago. (An æon is a very convenient geological unit indeed to reckon by; as nobody has any idea how long it is, they can't carp at you for a matter of an æon or two one way or the other.) Rock-salt is found in most parts of the world, in beds of very various ages. The great Salt Range of the Punjaub is probably the earliest in date of all salt deposits; it was laid down at the bottom of some very ancient Asiatic Mediterranean, whose last shrunken remnant covered the upper basin of the Indus and its tributaries during the Silurian age. Europe had then hardly begun to be; and England was probably still covered from end to end by the primæval ocean. From this very primitive salt deposit the greater part of India and Central Asia is still supplied; and the Indian Government makes a pretty penny out of the dues in the shape of the justly detested salt-tax--a tax especially odious because it wrings the fraction of a farthing even from those unhappy agricultural labourers who have never tasted ghee with their rice.
The thickness of the beds in each salt deposit of course depends entirely upon the area of the original sea or salt-lake, and the length of time during which the evaporation went on. Sometimes we may get a mere film of salt; sometimes a solid bed six hundred feet thick. Perfectly pure rock-salt is colourless and transparent; but one doesn't often find it pure. Alas for a degenerate world! even in its original site, Nature herself has taken the trouble to adulterate it beforehand. (If she hadn't done so, one may be perfectly sure that commercial enterprise would have proved equal to the occasion in the long run.) But the adulteration hasn't spoilt the beauty of the salt; on the contrary, it serves, like rouge, to give a fine fresh colour where none existed. When iron is the chief colouring matter, rock-salt assumes a beautiful clear red tint; in other cases it is emerald green or pale blue. As a rule, salt is prepared from it for table by a regular process; but it has become a fad of late with a few people to put crystals of native rock-salt on their tables; and they decidedly look very pretty, and have a certain distinctive flavour of their own that is not unpleasant.
Our English salt supply is chiefly derived from the Cheshire and Worcestershire salt-regions, which are of triassic age. Many of the places at which the salt is mined have names ending in _wich_, such as Northwich, Middlewich, Nantwich, Droitwich, Netherwich, and Shirleywich. This termination _wich_ is itself curiously significant, as Canon Isaac Taylor has shown, of the necessary connection between salt and the sea. The earliest known way of producing salt was of course in shallow pans on the sea-shore, at the bottom of a shoal bay, called in Norse and Early English a wick or wich; and the material so produced is still known in trade as bay-salt. By-and-by, when people came to discover the inland brine-pits and salt mines, they transferred to them the familiar name, a wich; and the places where the salt was manufactured came to be known as wych-houses. Droitwich, for example, was originally such a wich, where the droits or dues on salt were paid at the time when William the Conqueror's commissioners drew up their great survey for Domesday Book. But the good, easy-going mediæval people who gave these quaint names to the inland wiches had probably no idea that they were really and truly dried-up bays, and that the salt they mined from their pits was genuine ancient bay-salt, the deposit of an old inland sea, evaporated by slow degrees a countless number of ages since, exactly as the Dead Sea and the Great Salt Lake are getting evaporated in our own time.
Such, nevertheless, is actually the case. A good-sized Caspian used to spread across the centre of England and north of Ireland in triassic times, bounded here and there, as well as Dr. Hull can make out, by the Welsh Mountains, the Cheviots, and the Donegal Hills, and with the Peak of Derbyshire and the Isle of Man standing out as separate islands from its blue expanse. (We will beg the question that the English seas were then blue. They are certainly marked so in a very fine cerulean tint on Dr. Hull's map of Triassic Britain.) Slowly, like most other inland seas, this early British Caspian began to lose weight and to shrivel away to ever smaller dimensions. In Devonshire, where it appears to have first dried up, we get no salt, but only red marl, with here and there a cubical cast, filling a hole once occupied by rock-salt, though the percolation of the rain has long since melted out that very soluble substance, and replaced it by a mere mould in the characteristic square shape of salt crystals. But Worcestershire and Cheshire were the seat of the inland sea when it had contracted to the dimensions of a mere salt lake, and begun to throw down its dissolved saline materials. One of the Cheshire beds is sometimes a hundred feet thick of almost pure and crystalline rock-salt. The absence of fossils shows that animals must have had as bad a time of it there as in the Dead Sea of our modern Palestine. The Droitwich brine-pits have been known for many centuries, since they were worked (and taxed) even before the Norman Conquest, as were many other similar wells elsewhere. But the actual mining of rock-salt as such in England dates back only as far as the reign of King Charles II. of blessed memory, or more definitely to the very year in which the 'Pilgrim's Progress' was conceived and written by John Bunyan. During that particular summer, an enterprising person at Nantwich had sunk a shaft for coal, which he failed to find; but on his way down he came unexpectedly across the bed of rock-salt, then for the first time discovered as a native mineral. Since that fortunate accident the beds have been so energetically worked and the springs so energetically pumped that some of the towns built on top of them have got undermined, and now threaten from year to year, in the most literal sense, to cave in. In fact, one or two subsidences of considerable extent have already taken place, due in part no doubt to the dissolving action of rain water, but in part also to the mode of working. The mines are approached by a shaft; and, when you get down to the level of the old sea bottom, you find yourself in a sort of artificial gallery, whose roof, with all the world on top of it, is supported every here and there by massive pillars about fifteen feet thick. Considering that the salt lies often a hundred and fifty yards deep, and that these pillars have to bear the weight of all that depth of solid rock, it is not surprising that subsidences should sometimes occur in abandoned shafts, where the water is allowed to collect, and slowly dissolve away the supporting columns.
Salt is a necessary article of food for animals, but in a far less degree than is commonly supposed. Each of us eats on an average about ten times as much salt as we actually require. In this respect popular notions are as inexact as in the very similar case of the supply of phosphorus. Because phosphorus is needful for brain action, people jump forthwith to the absurd conclusion that fish and other foods rich in phosphates ought to be specially good for students preparing for examination, great thinkers, and literary men. Mark Twain indeed once advised a poetical aspirant, who sent him a few verses for his critical opinion, that fish was very feeding for the brains; he would recommend a couple of young whales to begin upon. As a matter of fact, there is more phosphorus in our daily bread than would have sufficed Shakespeare to write 'Hamlet,' or Newton to discover the law of gravitation. It isn't phosphorus that most of us need, but brains to burn it in. A man might as well light a fire in a carriage, because coal makes an engine go, as hope to mend the pace of his dull pate by eating fish for the sake of the phosphates.
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Falling in Love; With Other Essays on More Exact Branches of ScienceChapter X: Part 10
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