Once a Week (magazine)/Series 1/Volume 3/Out of the depths

OUT OF THE DEPTHS.

 

 

Not many evenings ago, some half-dozen pairs of bright eyes were peeping by turns through our microscope. Dainty fingers were pressed into obstinate left eyes which would not keep shut, and pretty mouths were twisted into agonising contortions in the effort to see all that could be seen. “Ohs!” and “Ahs!” together with all the usual feminine expressions of admiration, had been frequent and emphatic, when, upon putting the last three slides of our series (purposely reserved as a final bonne bouche) upon the stage of the instrument, the common delight culminated in a general exclamation of, “Oh, how sweetly pretty! The loveliest little shells!” Each refractory left optic was punished again and again in repeated examinations of the objects, and on all hands we were assailed by the questions: “What are they? and where do they come from?”

Now, although we all know it is often easier to ask than to answer a simple question, it does seem somewhat strange that we should make a long pause before replying, or that we should feel much difficulty in telling all about so very small a matter. Three slips of glass, three inches long and an inch broad, with as much fine white dust in the centre of each as would cover a threepenny-piece, do not look like a very trying subject to be examined upon: each slip, too, is labelled with the name of the object it carries, as well as a note of the locality from which it was procured; but these do not help us much; the names are long and unintelligible to uninitiated ears. Perhaps if we give them here, the reader will understand our embarrassment; he will at least see what hopeless things they would be to offer as an explanation to a lady’s untechnical but inquiring innocence; nay, possibly, if we have been fortunate enough to raise his curiosity, he may not himself be disinclined to listen, perhaps, in company with our fair friends, while we attempt an answer to the questions, What they are? and whence do they come? The labels read respectively as follows: 1. “Foraminiferæ—Atlantic soundings.” 2. “Polycystinæ—Atlantic soundings.” 3. “Diatomaceæ—Atlantic soundings.”

These are long words, as we said, and convey to most minds nothing very clearly, except a notion that the fine white dust has come in some way from the Atlantic. And so in truth it has. The three hard names represent the chief products of the sea-floor of that great ocean; and the tiny slides before us contain the remains of plants and animals brought up by the sounding-line from their dark home, some two miles beneath the surface of blue water. Let us see if these strangers from a far-off unknown region can be made to tell us something, as they lie beneath our microscope, of themselves and the mysterious hidden realm from which they come. We may suppose such atomies can scarcely tell us much, yet the vaguest story of their lives and destinies cannot but interest us. From the earliest times there has always existed some strong charm in the unknown recesses of the watery world. Ever since the old Hellenic poets saw

“Far in the wine-dark depths of the crystal, the gardens of Nereus,”

the imagination of man has delighted to people the clear river or the restless sea with fair semi-human forms. The old-world dreams of Siren, Triton, and Naiad are perpetuated in the later legends of Undine and the Lurleyberg; and our own great master-poet has perhaps drawn no more lovely figure than his “virgin daughter of Locrine”—the river-born Sabrina. The most matter-of-fact man has, when lounging by the shore, been sometimes attacked with the strong desire, if not to people the subaqueous realms of lake or sea with imaginary beings, at least to penetrate the shrouding veil of water, and to discover what are the beauties and what the forms he feels lie hidden beneath the wave. Some men there are, indeed, in whom this wish has grown to be a passion. It is not long since two widely-known and enthusiastic naturalists, possessed with this strong desire to know, prepared the necessary apparatus, and at some risk of life invaded the sea-god’s dominions. Thence they have sent up to us an eye-witness’ report of submarine manners and customs, and told us how the world goes on at the fifty-fathom line. Many a busy dredge, too, has been scraping for years past at the sea-floor, wherever it can be reached, bringing ever new facts before quick eyes and thoughtful brains; till in these times we begin to get a tolerably intimate knowledge of the complicated economies of the water-world; at least in such depths as our researches can be made with ordinary appliances.

Lately, one of the most eminent of English scientific men (now, alas! no more), has attempted to map out the minuter features of these regions, so far as animal life is concerned, with considerable accuracy. The physical geography (if we may so call it) of European sea-bottoms is now a science in which so many facts have been registered, and so many observations made, that practically the waters of our bays and firths have been rolled back for us, and the treasures they cover laid bare to our view. But of those profounder depths, far out in what sailors call “blue water,” neither poet or naturalist have as yet much news to tell us. Here the diving-dress and dredge are alike useless, and even the sounding-line long failed to fathom these tremendous abysses, much less to bring up thence any reliable evidence of their formation or inhabitants. The art of deep sea-sounding—which many, we believe, consider to be merely a thing of every-day life at sea, a simple matter of a string and a lead—is of decidedly recent origin. Human science and ingenuity, which had gauged the heavens and measured our earth’s distance from remotest visible planets; which had sounded abyss after abyss of firmamental space, and brought one faint nebula after another within resolvable distance; stood baffled in the effort to tell the depth of mid-ocean. Many were the trials made to sound in deep water, which all proved failures. The old-fashioned “lead” sunk and sunk endlessly, and sent up no shock to tell when the bottom had been reached: currents which seized the sinking line, dragged it out by thousands of fathoms, and would do so till every reel was emptied. Ingenuity was almost exhausted in new methods. Charges of gunpowder were exploded beneath the waves in the hope that the echo from the sea-floor would reach the surface. Experiment would furnish data for determining the rate at which sound travels in water, and the depth was to be ascertained by computation from the time occupied by the passage of such sound, caused by the explosion, to the bottom and back again to upper air. The theory was pretty; but, alas for fact! in the stillness of the calmest night no reverberation ever reached the listeners. Instruments were made in which a column of atmospheric air should register the aqueous pressure it sustained below, and thus (again by calculation) give the required information; but, pressed upon by such a volume of liquid, nothing could be made sufficiently strong to bear the strain, and so this, too, failed. Sinkers, with screw-propellers attached, were tried, in which the screw made a certain number of revolutions for every fathom of its descent, but it would not do. Electro-magnetism was pressed into the service (what errand under the sun has not electrical agency been set to do?), but without avail: the “blue water” mocked at every effort to gauge it.

At length, after innumerable discomfitures, a simple suggestion led the way to a solution of the difficulty. In all attempts hitherto made to sound with an ordinary “lead” the shock produced by contact with the ground was relied upon for an indication of the depth; in practice it was found that no such shock was ever communicated, but that the line would continue running out endlessly without giving the slightest hint of bottom. Casts made upon this theory gave the astounding depths of thirty, forty, and fifty thousand fathoms, mile after mile of line being swallowed up by the currents. The proposal which paved the way to success was this. To time the hundred fathom marks upon the sounding line as they left the reel, and by using always a line of the same make, and sinker of the same size and weight, to endeavour to establish some law of descent. It was tried, and within a very short time succeeded. The mean of many experiments gave a certain period for the sinking of the first hundred fathoms, another greater period for the second hundred, and so on up to thousands. Now, until the lead has reached the bottom, it will drag out the line at a constantly decreasing but ascertained speed; once there, however, the currents begin to act upon the twine now no longer kept tense by weight; this is the moment at which the true sounding has been accomplished, and its arrival will be very evidently marked by a change in the rate at which the twisted hemp descends; for the force of the currents being of constant intensity will produce an uniform instead of a variable motion, and the fathom-marks will pass more slowly and at equal intervals over the reels. After a few trials this plan was found to give results which might be considered reliable; soundings on being many times repeated over the same spot checking each other with surprising accuracy. The main part of the problem was solved, but there was yet much to be done: though the heavy shot would drag the line to the bottom, it could not afterwards prevent its being drifted perhaps hundreds of fathoms from the perpendicular, and to lift the sinker again to the surface was a complete impossibility; thus though ground was reached and its distance from the surface measured, its nature and peculiarities remained unknown as before. This difficulty also was conquered in the end as our three little slides will testify. A midshipman of the U. S. Navy, and coadjutor of Lieutenant Maury’s, named Brooke, devised a simple method by which the need of raising the sunken shot was done away with. Through a hole drilled right through the ball he passed a small wire, allowing it to project some few inches at both ends; one extremity of the wire he fashioned into a little cup, and to the other he attached the sounding line; the sinker thus prepared was hove, and upon the projecting cup coming in contact with the ground an ingenious disengaging apparatus detached the 32-pounder altogether from the wire, and the lightened line came merrily up again from the deep, leaving its bulky companion buried in the Atlantic ooze, but itself returning freighted with the long desired riches from below. It was not much evidence to all appearance which the witness brought; a thimble full of white clay, more or less “stiff,” was the only product of every cast. Notwithstanding that countless soundings in “blue water” have now been taken, the result has been the same in every case, and the whole sea-floor of the North Atlantic, with the exception of the shallower waters nearer shore, is proved to consist exclusively of this whitish-coloured clay or “ooze.” In some places it is of considerable stiffness, while in others it “has covered the depths of the ocean with a mantle delicate as the macled frost and light as the undrifted snow flake on the mountain.” Is there, then, no life, no trace of living thing nourished in the great sea’s bosom? Does vitality cease altogether at certain depths, and is this mighty water world but a barren desert after all? Such, doubtless, were among the questions first asked by expectant and, to say truth, somewhat disappointed men, as they examined and reexamined that little cup of clay, and such are the questions which may still be asked without a really reliable answer. The microscope has indeed taught us, as we have seen to-night, that the “ooze” has once held life; but evidence is wanting still to determine whether the great basin of the Atlantic should be considered as a teeming hive of active vitality, or but as a gigantic graveyard. For ourselves we believe the first. True, life lessens and organisations grow few and low in very deep water; but so abundant is it everywhere, that we find it less difficult to believe these delicate creatures have died and made no sign in the long passage from their dark home to the stage of the microscope, than that there should be one absolutely life-forsaken spot within the limits of our world; the singular uniformity of the deposits also forbids the idea that they were laid down by drifts and currents from distant sources; had currents only been at work, the results of their labours would exhibit a much more miscellaneous character; but instead of this, every new cast brings up the same organisms, and that, too, without the slightest admixture of any foreign matter whatsoever; not a visible fragment of shell, no sand, not a pebble even has the sounding line brought up, plainly proving to our thinking that our minute friends have been truly found “at home.” These morsels of clay, then, which seem at first but poor waking realities after the dreams men have dreamed of the wonders that were perhaps to be revealed, are no common mould, not a particle of them but was once a living organism.

And now think of this: if it were at first disappointing to find no visible evidence of busy life, strange forms of unknown plants and animals, surely there is something grandly startling in the consideration of what the Atlantic floor really is. Picture if you can the thousands of square miles over which this living snow-white carpet of unknown thickness is spread, and standing in imagination upon the precipitous edges of the hills which rise to form our island, look down thence into the boundless abyss some 1700 feet below, in which, hidden from all human eyes, in darkness and perfect stillness, slowly—oh! how slowly—these little Foraminiferæ and Polycystinæ are building up a new chalk world, perhaps the white cliffs of another possible Albion. For we cannot but think that in Midshipman Brooke’s “cup” lies the true solution of the great geological chalk difficulty; long have we suspected that the little chambered shells (of similar family to these), so abundant in this formation, were themselves (they and their fragments) the producers of the material in which they appear as fossils. Year after year have geologists advanced in the belief that the cretaceous period, about whose origin there have been so many uncertainties, must have owed its existence to long-continued accumulations of the remains of primæ val Foraminiferæ; and here surely is a proof there is no gainsaying, that the guess was right.

Turning from this wide and general view of our subject, we set ourselves to look a little more closely at these new comers from a mysterious home, not without an idea that some among them may at least turn out to be hitherto unknown forms of life. One glance of the practised microscopist, however, detects a well-known character in each; these dwellers in the deep sea are no new creations, we recognise them all as old familiar friends.

We have already said that the chalk furnishes us with countless examples of the Foraminiferæ in a fossil condition, but their living congeners are also to be found flourishing on every shore. Let us say a word or two on their nature and peculiarities.

Far down among the lowest forms of animal life with which we are acquainted, is the strange organism known as the Proteus (Amœ ba diffluens); it is nothing more than a small lump of jelly without integument, but endowed with the capability of moving and eating, if eating it may be called. Special organs for this or any other function it has none, but the whole of the gelatinous body covers and encloses within itself any atom capable of affording nutrition, and becomes mouth and stomach both, when occasion requires. Closely allied to the Proteus is another genus, which we cannot describe better than as an Amœba invested with a calcareous covering. If we imagine a delicate discoid spiral shell of elegant form, marked with curved and diverging grooves, and inhabited by a tiny piece of clear jelly without organs, but capable of projecting the substance of its body (called “sarcode”) in the finest possible filaments through perforations in the surface of its shell, this first principal representative of the deep sea soundings is before us. In our prepared and mounted specimen it is the shell alone which we see; the delicate tenant has of course long since perished, and its beautiful envelope alone is left; turning to our tank of sea-water, however, we can soon, by dint of prying pretty closely among the weeds, secure a living individual for inspection, and placing it beneath the lens, we shall see, to quote a good naturalist and accurate observer: “From the sides of the opaque shell protruding tiny points of the clear sarcode; these gradually and slowly—so gradually and slowly that the eye cannot recognise the process of extension—stretch and extend their lines and films of delicate jelly, till at length they have stretched right across the field of view. These films are as irregular in their forms as the expansions of the sarcode of the Amœba, with which they have the closest affinity. Their only peculiarity is their tendency to run out into long ribbons or attenuated threads, which, however, coalesce and unite whenever they come into mutual contact, and thus we see the threads branching and anastomosing with the utmost irregularity, usually with broad triangular films at the point of divergence and union. There can be no doubt that the object of these lengthened films, which are termed ‘pseudopodia,’ is the capture of prey or food of some kind; perhaps the more sluggish forms of minute animalcules or the simpler plants. These, the films of sarcode probably entangle, surround, and drag into the chambers of the shell, digesting their softer parts in temporary vacuoles, and then casting out the more solid remains just as the Amœba does.” By means of these “pseudopodia” the animal also drags itself along over a fixed surface. Such is the Foraminifer of our own seas, and such too the atomies of the Atlantic basin. Of the Polycystinæ we shall find no living representatives in these latitudes, though even if we did, the above description would scarcely need to be altered to serve for them as well, save in so far as their shells or envelopes are concerned; these, as we have an opportunity of seeing, are of more various forms and more elegant design that those of their near relations, and it was in admiration of them the loudest exclamations and prettiest diminutives were applied by our bright-eyed investigators. And our third slip of glass, what shall we say of that? Its history is a somewhat more involved and complicated matter. Viewed with a high magnifying power several strange and beautiful forms are visible as composing the dust; there are little discs of purest glass reticulated like the engine-turned back of a watch, other discs similarly reticulated and fringed with projecting processes like the rowel of a spur; triangular forms of the most delicate net-work, and oval or square pieces of exquisite chasing or tracery—surely these must be shells. And shells they are truly, though these minute objects have never served as coverings for anything but vegetable matter; each lovely reticulated “valve,” siliceous in its nature and of indestructible hardness, has been the envelope of as true a plant as the tree or flower. Living representatives of each Atlantic species are known to us, nor if we take a casual glance at one of these under the microscope will it be a matter of surprise to anyone who sees it for the first time, to learn that ever since the first discovery of the great family of Diatomaceæ (a discovery almost contemporaneous with the introduction of the microscope), their true character and place in the kingdoms has been a subject of constant dispute. These little discs, while living, have not only the general appearance of some fantastic kind of shell, but are endowed with a very marked power of locomotion, which has, moreover, every semblance of being as much under the influence of volition as the movements of any of the infusorial animalcula; it is not then much to be wondered at that they should have been bandied about for years between the animal and vegetable dominions, as their respective affinities to either appeared to their observers to predominate; they are now (we think finally) referred to the latter kingdom, and take place with, or rather below, the lowest form of fungi, as the humblest types of that boundless and magnificent section of creation. Thus, then, we complete the examination of our treasures, and find that the depths of ocean are, like this green earth, peopled with living tenants and enriched with vegetable existences; widely different, perhaps, from the kinds we dreamed might lie in them; forms, without the newness, size, or gorgeousness that our fancy had prefigured, yet rightly fitted all to the work set them to do, and that work (doubt it not), little as we yet know of its extent or direction, one day to be disclosed as no mean or unworthy example of Nature’s slow, sure, yet stupendous doings. We replace our little slides in the cabinet, yet we cannot wholly leave them without lingering for a moment over this one imagination, fantastic though it may appear, to which they have given birth. These Diatoms and Polycystinæ, humblest forms of vitality, do yet seem, in those wonderful peculiarities of their coverings (which, until we had become acquainted with these lower organisms, were ever considered as exclusively typical of infinitely higher races of animals), to stretch out an almost prophetic finger, pointing from the sunless sea-floor, where the first faint glimmerings of the flame of life flickers through the darkness, to the coming time (distant, it may be, unnumbered ages) when a more perfected creation shall enter on the scene slowly preparing for its advent. And now does any reader ask, Have we not been pursuing an useless theme? Is there any practical result to be accomplished by these researches? At present, we confess, not much. The Atlantic cable, whose very existence is referable to the facts made known by deep-sea sounding is, as yet, a failure; still, let all observers work and wait; hasty men, with a contempt for scraps of information and thimblefuls of knowledge, will meanwhile do well to remember Franklin’s question, “What is the use of a new-born babe?” None can solve that unanswerable riddle, yet there is no one of us who doubts the possibilities that may be hidden in that germ of life.

This we believe to be true. No honest work was ever done, no careful effort ever made to get at one of Nature’s smallest secrets without some useful results following in due time. And so we prize our Atlantic soundings, not doubting in the least that patience, continued observation, and experiment will yet bring to our knowledge hidden facts, new laws, and undreamed-of wisdom out of the depths.

D. P.