Midland Naturalist/Volume 01/Review (The Voyage of the Challenger)

by Edward William Badger

Review.

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The Voyage of the "Challenger".—The Atlantic: A preliminary account of the general results of the exploring voyage of H.M.S. "Challenger," during the year 1873 and the early part of the year 1876, By Sir C. Wyville Thomson, Knt., LL.D., D.Sc., F.R.SS.L.&E., &c., Director of the Civilian Staff of the "Challenger" Exploring Expedition, 2 vols. Published by the authority of the Lords Commissioners of the Admiralty. London: Macmillan and Co. 1877. Price 45s.

These handsome, interesting, and instructive volumes are the latest contribution to the history of deep-sea investigation. They follow a natural sequence the author's former work, "The Depths of the Sea," which gave an account of the general results of the dredging cruises of the "Lightning" and "Porcupine," 1868-69-70, the scientific work of which was under the direction of Sir Wyville Thomson, Dr. Carpenter, and Mr. J. Gwyn Jeffreys, These volumes in like manner deal with the Atlantic portion of the more recount voyage of H.M.S. "Challenger."

It must be borne in mind that these two volumes are only a preliminary instrument of the authoritative account of the general results of the "Challenger" voyage, and that years may yet elapse before the complete results can be published. From the address of Sir Joseph Hooker, at the recent anniversary of the Royal Society, we learn that the publication of the biological results of the Expedition have been arranged for by the Lords of the Treasury in communication with the Council of the Society, and the munificent sum of £25,000 placed at Sir Wyville Thomson's disposal for bringing them out with a completeness and in a form worthy of the expedition and the nation. Sir W. Thomsen has, with the approval of the Council and the Government, chosen for his collaborators the ablest living specialists, and this irrespective of their nationality, Our own country has, with but few exceptions, supplied entirely competent and willing workers in most of the departments, while their association with such naturalists as Agassiz and Hæckel cannot fail to be gratifying to themselves and assuring to the public.

The primary object of the expedition was, as our readers are aware, to explore the conditions of the deep sea, and the staff consequently took every possible opportunity of making deep-sea observations, and in these volumes the results achieved are recorded with such care and exactitude as to make them most valuable and instinctive to men of science, and yet so pleasingly and with so much that may be described as of a popular character, as to make the volumes available for, and enjoyable by, those who read mainly for pleasure. The dredgings were made in the greatest depths, and also from time to tine in shallow water in the most remote regions, and thus many undescribed animal forms were acquired; collections of land animals and plants were likewise made on every available occasion, and consequently naturalists of all kinds will find in these pages matter of interest to them.

From the time when the "Challenger” left Sheerness, on December 7th, 1872, to her arrival at Spithead on 24th May, 1876, she traversed a distance of 68,890 nautical miles, and at intervals about 120 miles apart 362 observing stations, of which nearly  200 were in the Atlantic, were established, The observations made at each of these Were, as far as circumstances would admit, the following, after the position of the station had been ascertained:—1.—The exact depth was determined. 2.—A sample of the bottom, averaging from 1oz, to 1lb, in weight, was obtained, 3.—A sample of the bottom water was secured for physical and chemical examination. 4 —The temperate was determined. 5.—Generally a fair sample of the bottom fauna was obtained by dredge or trawl, 6.—The fauna of the surface, and of intermediate depths, was examined by the use of the tow net. 7.—A series of temperature observations were made at different depths from the surface to the bottom. 8.—Samples of sea water were obtained from different depths. 9.—Atmospheric and other meteorological conditions were carefully observed and noted. 10—The direction and rate of the surface current was determined. 11.—At a few stations an attempt was made to ascertain the direction and rate of movement of water at different depths.

Of the many points on which the expedition haw thrown light, we can only select a few for this notice. Many of our readers will, no doubt, recall the discussions which have taken place as to the origin of the portion of sea-bottom covered with what is known as "globigerina-ooze," or "modern chalk," which consists usually of a creamy surface layer, made up of little else than the shells, most of them almost entire, of Globigerina, Pulvinulina, and Orbulina, With a relatively small proportion of finely divided matter, consisting chiefly of coccoliths and rhabdoliths, and a still smaller proportion of the spines and tests of radiolarians and fragments of the spicules of sponges, &c. Below this layer occurs another, an inch or two in thickness, somewhat more firm in consistence, in which most of the shells of all kinds are more or less broken up, and their fragments cemented together by a calcareous paste, the remit of the complete disintegration of many of them, and beneath this a nearly uniform calcareous paste, coloured grey by decomposed organic matter, and containing whole and fragmentary shells only sparsely scattered through it (pp. 206-7, vol. I.) Mr. Murray, one of the naturalists of the expedition, paid great attention to the question of the origin of this calcareous formation. Very early in the voyage he formed the opinion that all the organisms entering into its composition at the bottom are dead, and that all of them live abundantly at the surface and at intermediate depths over the globigerina-ooze area, the ooze being formed by the subsiding of theses shells to the bottom after death (p. 208, vol. I.) This, although not a new view, was a disputed one, Dr. Carpenter and Sir Wyville Thomson being formerly among these who thought that the evidence was exclusive that the foraminifera which formed the globigerina-ooze lived on the bottom. Sir Wyville (p. 210, vol. I) now acknowledges that he was mistaken, and he is of opinion that it may "be taken as proved that all the materials of such deposits (with the exception, of course, of the remains of animals, which we now know to live at the bottom at all depths, and which occur in the deposit as foreign bodies) are derived from the surface." "Mr. Murray finds the closest relation to exist between the surface fauna of any particular locality and the deposit which is taking place at the bottom."

The voyage has made known to us a number of new and beautiful forms of Sponges. One of these, Euplectella suberea, a beautiful and singular addition to these forms of European fauna, is figured at page 139, vol. I. It belongs to a very special group of sponges called the Hexactinellidæ, because the siliceous spicules throughout the family appear to be six-rayed. It is an old family abounding in many graceful shapes in the beds of chalk and grassland of the south of England, but until lately the fossil "ventriculites” were supposed to be extinct, and the discovery of their descendants living in the modern chalk beds of the Atlantic was one of the most interesting of the many corroborative evidences in favour of the view of the "continuity of the chalk."

The expedition has much enlarged our knowledge of deep sea fauna. It has introduced us not only to now sponge forms but to numbers of new crustaceans, corals, sea urchins, star fishes, bryozea, and fishes. The observations on the "Gulf-stream" and the fauna of the "gulf weed" (Soryassum baeriferum) are particularly interesting.

During such a protracted voyage opportunities for landing on shore were always gladly made use of, and some of the descriptions of what was seen on these occasions will, we have no doubt, be among the most attractive portions of the narrative to general readers. We may point out the description of the Bermudas Islands, and the formation and characteristic peculiarities of coral reefs as a good specimen of Mr. Wyville's descriptive powers. The geology of the Bermudas is sketched slightly, but with much precision. Some curious particulars are given of "Sand-glacier" at Elbow Bay, on the southern shore of the main island. The sand has entirely filled up a valley, and is steadily progressing inland in a mass five and twenty fact thick. It is covering up cottages, and has overwhelmed a cedar wood. The only way of stopping it artificially, says our author, is to cover it with vegetation. If planted in large numbers and tended and watered for a time it seems that oleanders and the native juniper will grow in the pure sand, and if they once take root the motion of the sand ceases. Some native plants, which form peculiar vegetation, sending out enormously long runners or roots—such as Ipomœa pescaprae and Coccolaba uvifera, and the crabgrass Agrostis véryiniea—then take hold of it and it becomes permanently fixed. The outer aspect of the sandhill of course slopes downwards towards the sea, and whenever its progress landward—its growth—has been arrested the tendency of the incoherent mass is to travel back again by gravitation and the action of rain; accordingly it is not unusual to be told that one of these coulées is gradually disappearing.

Among the more original and striking results of the expedition is the conclusive proof that "the conditions of the bottom of the sea to all depths are not only such as to admit of the existence of animal life, but are such as to allow of the unlimited extension of the distribution of animals high in the zoological series, and closely in relation with the characteristic fauna of shallower zones" (page 203, vol. I.) Our readers will scarcely need reminding that until within recent years the general belief was that beyond a certain very moderate depth in the ocean, organic life entirely ceased, and all was death and darkness.

The two volumes are illustrated by nearly 300 woodcuts of first-rate excellence, many of them we feel inclined to think unsurpassable. By the courtesy of Messrs. Macmillan and Co. we are enabled to

Fig. 4.

Fig. 5.

present our readers with three specimens of them, they are all forms of the new order "Challengerida," "the only new group," says Sir Wyville Thomson, "of higher than generic value which has come to light during the Challenger Expedition." Figure 3 represents the type genus Challengeria, magnified 400 times. Figures 4 and 5 represent forms of the Challengerida. This order has apparently hitherto escaped observation. These forms are extremely minute, although some of them are pearly the size of the smaller Radiolarians, which they approach in certain features, About thirty species have been met with during the Challenger Expedition. There are numbers of charts, showing the routes and observing stations, tables of temperature and other meteorological information, a contour map of the Atlantic, and an exquisite vignette portrait of Sir Wyville Thomson, engraved by Mr. C. H. Jeens. Author, Artists, and Publishers are to he congratulated on the results of their several labours, and we venture to think that the volumes will attain a deservedly wide and enduring popularity.E. W. B.

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