the ice-cap' nearer its Polar centre, we have at present no means of knowing; but it must doubtless be kept down by the facility of downward flow in almost every direction towards its periphery of 10,000 miles.

In regard to the animal life of the deep sea, the 'Challenger' researches do not seem likely to yield any new general result of striking interest. Our previous work had shown that a depth of three miles, a pressure of three tons on the square inch, an entire absence of sunlight, and a temperature below 32°, might be sustained by a considerable number and variety of animal types; and this conclusion has been fully confirmed and widely extended. Many specimens have been brought up alive from depths exceeding four miles, at which the pressure was four tons on the square inch, considerably exceeding that exerted by the hydraulic presses used for packing Manchester goods. Even the 'protected' thermometers specially · constructed for deep-sea sounding were frequently crushed; and a sealed glass tube containing air, having been lowered (within a copper case) to a depth of 2,000 fathoms, was reduced to a fine powder almost like snow, by what Sir Wyville Thomson ingeniously characterised as an implosion; the pressure having apparently been resisted until it could no longer be borne, and the whole having been then disintegrated at the same moment. The rationale of the resistance afforded by soft-bodied animals to a pressure which thus affects hard glass, is simply that they contain no air, but consist of solids and liquids only; and that since their constituent parts are not subject to more than a very trifling change of bulk, while the equality of the pressure in every direction will prevent any change in their form, there is really nothing to interfere with the ordinary performance of their vital functions.

The entire absence of solar light, which constitutes another most important peculiarity in the conditions of deep-sea life, would seem at first sight to be an absolute bar to its maintenance. Experimental evidence has not yet, I believe, been obtained of the direct penetration of the solar rays to more than 100 fathoms; but as I dredged slowgrowing red calcareous Alga (true corallines) in the Mediterranean at a depth of 150 fathoms (at, or below, which Edward Forbes also would seem to have met with them), the actinic, if not the luminous, rays must probably penetrate to that range. Below what Edward Forbes termed the coralline zone, it would seem impossible that any other type of vegetable life can be sustained, than such as have the capacity of the fungi for growing in the dark; living, like them, upon material supplied by the decomposition of organic compounds. Such lowly plants have been found by Professor P. M. Duncan in corals dredged from more than 1,000 fathoms' depth.

Upon what, then, do deep-sea animals feed? In the early stage

of this inquiry, it was ascertained by Dr. Frankland that the samples of water procured by the 'Porcupine,' not only at considerable distances from land, but also from bottoms exceeding 500 fathoms' depth, contained so much organic matter not in a decomposing state, that animals having a large absorbent surface, and requiring but a small proportion of solids in their food, might be sustained by simple imbibition. And an adequate provision for the continual restoration of such material to the ocean-water seemed to be made by the surface-vegetation which fringes almost every sea-margin, and which occasionally extends itself over large tracts in the open ocean, as, notably, in the Sargasso Sea. But the Challenger's' researches have thrown a new light on this question, by showing that the animals of the deep sea are largely dependent for their food upon the minute organisms and the débris of larger ones, which are continually falling to the bottom from the upper waters.

This débris (says Mr. Moseley) is no doubt mainly derived from the surface Pelagic flora and fauna, but is also to a large extent composed of refuse of various kinds washed down by rivers, or floated out to sea from shores, and sunken to the bottom when water-logged. The dead Pelagic animals must fall as a constant rain of food upon the habitation of their deep-sea dependents. Maury, speaking of the surface Foraminifera, wrote, 'The sea, like the snow-cloud, with its flakes in a calm, is always letting fall upon its bed showers of microscopic shells.' It might be supposed that these shells and other surface-animals would consume so long a time in dropping to the bottom in great depths, that their soft tissues would be decomposed, and that they would have ceased to be serviceable as food by the time they reached the ocean-bed. Such, however, is not the case, partly because the salt water of the sea exercises a strongly preservative effect on animal tissues, partly because the time required for sinking is in reality not very great.7

Of this Mr. Moseley assured himself by an experimental test, which indicated that the dead body of a floating salpa might sink to a depth of 2,000 fathoms in little more than four days, whilst its body might remain for a month so far undecomposed as to be serviceable as food to deep-sea animals. As land was neared, moreover, many interesting proofs were obtained of the feeding of deep-sea animals on débris derived from the neighbouring shores.

Thus, off the coast of New South Wales we dredged from 400 fathoms a large sea-urchin which had its stomach full of pieces of a sea-grass (Zostera) derived from the coast above. Again, we dredged from between the New Hebrides and Australia, from 1,400 fathoms, a piece of wood and half a dozen examples of a large palm-fruit as large as an orange. In one of these fruits, which had hard woody external coats, the albumen of the fruit was still preserved, perfectly fresh in appearance, and white, like that of a ripe cocoa-nut. The hollows of the fruits were occupied by two molluscs; the husks and albumen were bored by a teredo-like mollusc; and the fibres of the husks had among them small nematoid worms.

Branches of trees, also, and leaves of shrubs, in a water-logged condition, were occasionally brought up in the dredge from great s Ibid. p. 583.

Notes by a Naturalist, p. 582.

depths and their occurrence, as Mr. Moseley remarks, is of importance, not only to the naturalist, as showing that deep-sea animals may draw large supplies of food from such sources, but also to the geologist, as indicating the manner in which specimens of land vegetation may have been imbedded in deposits formed at great depths.

The entire absence of sunlight on the deep-sea bottom seems to have the same effect as the darkness of caves, in reducing to a rudimentary condition the eyes of such of their inhabitants as fish and crustacea, which ordinarily enjoy visual power; and many of these are provided with enormously long and delicate feelers or hairs, in order that they may feel their way about with these, just as a blind man does with his stick. But other deep-sea animals have enormously large eyes, enabling them to make the best of the little light there is in the depths, which is probably derived (as suggested in the report of the 'Porcupine' dredgings) from the phosphorescence emitted by many deep-sea animals, especially a certain kind of zoophytes. It seems certain,' says Mr. Moseley, 'that the deep sea must be lighted here and there by greater or smaller patches of luminous alcyonarians, with wide intervals, probably, of total darkness intervening; and very possibly the animals with eyes congregate round these sources of light.' It is remarkable that with such poverty of light there should be such richness of colour among deepsea animals. Although most deep-sea fish are of a dull black colour, and some white as if bleached, deep-sea crustaceans, echinoderms, and zoophytes usually exhibit more colour than the corresponding forms that inhabit shallow water. Thus the deep-sea shrimps, which were obtained in very great abundance, were commonly of an intensely bright scarlet; deep-sea holothurians are often of a deep purple; and many deep-sea corals have their soft structures tinged with a madder-colouring matter resembling that which occurs in surfaceswimming jelly-fish.

6

As was to be expected from the results of the Lightning' and 'Porcupine' dredgings, the more extended explorations of the 'Challenger' have shown that there still live in the sea-depths a number of animal forms which were supposed, until thus found, to be extinct, existing only as fossils. And large numbers of interesting new genera and species of known families of animals were obtained; whilst many forms which had been previously accounted of extreme rarity have proved to be really common, having a wide geographical range, and occurring in large numbers in particular spots. This is the case, for example, with the beautiful pentacrinus, a survivor from the old Liassic times, of which the living specimens preserved in all the museums of the world could have been counted on the fingers not many years ago, all of them having been brought up on fishing-lines from the neighbourhood of the West India Islands. As many as twenty specimens of a new species of this most interesting type,

however, had been brought up from a depth of 800 fathoms in one of the Porcupine' dredgings off the coast of Portugal. The Challenger' made a large collection, including several new species, from various localities. And yet more recently the dredgings of Professor Alexander Agassiz in the Gulf of Mexico have shown how thickly. many parts of the sea-bed are covered with these lily stars' mounted upon their long wavy stalks.

Those, however, who had expected results of greater zoological and paleontological importance from these explorations must confess to some disappointment:-

Most enthusiastic representations (says Mr. Moseley) were held by many naturalists, and such were especially put forward by the late Professor Agassiz, who had hopes of finding almost all important fossil forms existing in life and vigour at great depths. Such hopes were doomed to disappointment; but even to the last, every cuttle-fish which came up in our deep-sea net was squeezed to see if it had a Belemnite's bone in its back, and Trilobites were eagerly looked out for. We picked up no missing links to fill up the gaps of the great zoological family tree. The results of the 'Challenger's' voyage have gone to prove that the missing links are to be sought out rather by more careful investigation of the structure of animals already partially known, than by hunting for entirely new ones in the deep sea."

The work which has been already done by Mr. Moseley himself in this direction, contained in the memoirs he has presented to the Royal and Linnæan Societies, is of first-rate value. And if the whole, or even any considerable part, of the vast Challenger' collection shall be worked out by the various specialists among whom it has been distributed, with anything like the same completeness and ability, it cannot be questioned that the series of volumes in which the scientific results of this voyage will be embodied, will far surpass in interest and importance those reports of previous Circumnavigation Expeditions which are accounted models of their class.

WILLIAM B. CARPENTER.

Notes by a Naturalist, p. 587.

AGNOSTICISM AND WOMEN.

Ir is acknowledged on all sides that Agnosticism is gaining ground among men. It is not so thoroughly realised that in this case it must in the long run equally gain ground among women. This side of the question is not one that is often raised. Men do not see willingly that which they dislike to see, and there can be little doubt that the spread of Agnosticism among women would tend to make them discontented with the quiet home life which is often their only lot. It would, moreover, increase tenfold the cry of women for the right of employment in the more active lines of life at present denied to them. Men prefer to hope that women will be slow to drive logic to its ultimate end; that they will still cling with womanly inconsistency to all that is refining and soothing in the old creeds; and that the newer and colder lights of their husbands and brothers will only serve to eliminate from those creeds the elements of superstition and fear which are now considered so debasing. But in a day when intellect in women is valued more highly than it has ever been, they will not long be willing to hold a belief that is not shared by men. All around them they see the men they admire and reverence drawn away from the beliefs of the past. Progress allures and fascinates all, and the rational mind, as opposed to the instinct, is the god at whose shrine all desire to worship. With this atmosphere around them it is not possible that women, highly emotional in temperament and essentially timid in intellect, should long remain proof against it. But, granted that Agnosticism in the long run will grow among women as it has grown among men, how will it affect their interests and their employments? It may be replied that it will affect them no otherwise than it does men; but to make this reply is to forget that women are very differently constituted. Their nature and their pursuits are different. Few women-at least so far as society is framed at present-can have a profession. Few women can hope to take an active share in political life. Even if they gain the suffrage, the pride of their equality with men on this point will only suffice to give an excitement to a few days of political contest, or may possibly awaken a keener advocacy of their special prejudices. Some among them, by the help of a busy life spent in society, are carried along by the current; and a certain percentage, and these perhaps the happiest, are obliged to work for their own