NATURE 



409 



THURSDAY, MARCH 6, 1902. 



THE VOYAGE OF THE " VALDJVIA." 

 Alls den Tie/en des Weltmeeres, Schilderungen von der 

 deutschcn Tiefsee-expedition. \"on Carl Chun. (Jena : 

 Gustav Fischer, 1900.) Lief, i.-xii. Price 18 mk. 



ON the return of the German deep-sea expedition, 

 it was decided to issue a popular account of the 

 voyage and its results. Naturally this task fell to the 

 leader, and in the volume before us Prof. Chun acquits 

 himself of it. 



The work opens with a short review of the history of 

 deep-sea exploration, from the discovery by Sir John 

 Ross in the year 181S of living brittle-stars in 1000 

 fathoms of water to the outfitting of the German expedi- 

 tion in 1S98 — pages which will be read in this country 

 with a justifiable pride indeed, but also with the con- 

 viction that exertion is needed if we are still to hold 

 our own in scientific exploration. In enumerating the 

 problems which yet remain to be solved, and for the dis- 

 cussion of which his expedition was to furnish material, 

 Prof. Chun mentions the bionomics and embryology of 

 deep-sea animals, the distribution equatorwards of polar 

 organisms, and bipolarity, but he does not here refer to a 

 question of considerable interest which has been greatly 

 enlightened by the Valdivia's researches, the vertical 

 distribution of the mesoplankton, which has been found, 

 by the German expedition and by Dr. G. H. Fowler 

 independently at almost the same time, practically to 

 cease at about 1000 fathoms — a result which agrees 

 neither with the view previously held in some quarters 

 that pelagic life extended throughout the depth of the 

 ocean, nor with the opposite opinion that it did not exist 

 below two or three hundred fathoms. 



The route of the cruise was determined by the decision 

 to explore,as far as possible, portions of the ocean the deep- 

 water fauna of which was as yet imperfectly known. Two of 

 the most important of these being the South .Atlantic 

 and a great part of the Indian Ocean, the course decided 

 upon was one which, passing through the Faroe Channel 

 and thence southwards to the Canaries, followed roughly 

 the western coast of Africa to the Cape, then struck 

 south-west to Bouvet Island and south-east from Bouvet 

 Island to the neighbourhood of Enderby Land, traversed 

 the length of the Indian Ocean to the Nicobars, passing 

 Kerguelen, New Amsterdam and Sumatra on the way, 

 crossed from the Nicobars by Ceylon, the Maldives, 

 the Chagos and the Seychelles to Dar-es-Salaam, and 

 finally led back along the east coast of Africa, through 

 the Red Sea and Suez Canal, to the Mediterranean and 

 so home. Besides Prof. Chun, the expedition comprised 

 ten scientific members, a photographer and a conservator. 

 The vessel chosen was the Valdivia, a Hamburg to West 

 Indies liner of 2176 tons register, and considerable 

 alterations were made to fit her for the voyage, among 

 others the fitting up of a large ice-room, which was 

 found very useful in enabling deep-sea animals to be 

 examined alive by being kept at a low temperature. The 

 scientific equipment was very elaborate, and certain prac- 

 tical details are worth noting. Indiarubber accumulators, 

 used to take the weight of the nets and their wire, were 

 NO. 1688, VOL. 65] 



perished by the heat of the tropics, though fortunately 

 others of steel spring were at hand. The " Blake " dredge 

 proved less serviceable than a trawl, its iron frame cutting 

 too deep into the ooze. The bucket of the vertical net 

 was of glass and without filtering surfaces, whereby a 

 smaller quantity of plankton was gotten, but in better 

 condition. No doubt the quantitative net, built on 

 Hensen's pattern, which was carried was provided with 

 a porous bucket. Both Negretti and Zambra's up- 

 setting thermometer and one of the Siemens electrical 

 type proved useful, but the latter is said to need further 

 improvements. 



The history of the voyage is sketched in a series of 

 chapters. These are written in a light and popular vein, 

 and are beautifully illustrated by photographs of places 

 and natives, but only a few points in them call for notice 

 here. The important observations began when the 

 Canaries had been passed. In the Guinea Stream, the 

 low specific gravity of the water was found to be connected 

 with a peculiarity of the plankton, the spines and other pro- 

 cesses of which are longer than those of the forms found in 

 the north and south equatorial streams. Dredging here 

 gave poor results, but the deep-sea plankton is very rich. 

 In lat. 25' 26' S. was discovered, in 936 fathoms, a new 

 bank, believed to form part of a ridge (the "Walfish 

 ridge "), which parts the colder southern waters from the 

 tropics, much as the Iceland ridge fends off the Arctic 

 waters. The fauna of this bank is very rich. Careful 

 dredgmgs were also made on the Agulhas bank, from 

 which valuable results may be expected. There appears 

 to be here an intermingling of Atlantic and Indian forms 

 with typical Antarctic species, and Prof. Chun suggests 

 that the latter are relics of a time when these waters were 

 colder than at present. 



One of the most important results of the expedition 

 was the rediscovery of Bouvet Island in lat. 54" 26' S. 

 and long. 3° 24' E. The Valdivia was only able to estab- 

 lish the existence of a single volcanic island some five 

 miles by four, covered with an immense glacier, but the 

 possibility is not excluded that a second may exist, cor- 

 responding to Norris's "Thompson Island." The search 

 for this island in stormy weather amid mist and icebergs 

 seems to have been a fine piece of work. Dredgings in 

 the neighbourhood revealed a very rich fauna, inter- 

 mediate between that of the Magellan region and that of 

 Kerguelen, but with many new forms. Bouvet Island 

 appears to be near the point of a tongue of cold water 

 which extends northwards from the Antarctic region. 

 On leaving it, the Valdivia coasted along the edge of the 

 drift-ice which marks this tongue, in a south-easterly 

 direction, till she was confronted with the edge of the 

 pack-ice in the neighbourhood of Enderby Land. During 

 the whole of this course, the water was of great depth, 

 varying from 2000 to 3000 fathoms. The temperature 

 curve was also very interesting. Owing to the presence 

 of ice, the surface water is considerably cooler than that 

 of intermediate depths, the actually coldest layer (about 

 - I'^'j C.) being at 30-40 fathoms. Below this the 

 temperature rises, till at 300-400 fathoms it is i°7 C. 

 Then it falls gradually and, at the bottom, is — "5° C, 

 Naturally, a number of icebergs were met with in this 

 region, mostly of table form well known in the Antarctic 

 and often of immense size. .After a number of pages 



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