NA TURE 



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THURSDAY, AUGUST 15, i! 



THE THREE CRUISES OF THE ''BLAKE:' 



The Three Cruises of the "■Blake." Two Vols. By 

 Alexander Agassiz. Bulletin of the Museum of Com- 

 parative Zoology at Harvard College, Vols. XIV. and 

 XV., Cambridge, Mass. (Boston and New York : 

 Houghton, Mifflin, and Co., 1888.) 



IN these profusely illustrated volumes there is presented 

 to the general reading public the best and most com- 

 prehensive account of recent oceanographical investiga- 

 tions and speculations that has as yet been attempted. 

 These volumes have, moreover, a special value for all 

 who interest themselves in deep-sea researches, from the 

 descriptions that are given of the work carried on with so 

 much ability and industry by Mr. Agassiz and his fellow- 

 countrymen on the eastern and southern sea-boards of 

 the United States and in the West Indian seas. The 

 volumes abound with novel and ingenious views bearing 

 on nearly all the physical and biological phenomena of 

 the ocean ; and, whether we agree with the writer or not, 

 his opinions are none the less welcome and suggestive, 

 coming as they do from one who has for many years 

 taken a large part in the practical work connected with 

 the observations which he here undertakes to describe 

 and discuss. It does not seem possible to over-estimate 

 the credit due to the Government and the men who 

 initiated and h^ve carried through this excellent and ex- 

 tensive hydrographical survey of the deeper waters sur- 

 rounding the eastern shores of North America, nor to 

 value too highly the resulting additions to human know- 

 ledge. These positive additions to our knowledge of the 

 ocean will be fully acknowledged and appreciated by all 

 who desire to trace the causes that have led to the deve- 

 lopment of the surface features of the earth and the 

 existing conditions of life on our globe. 



After an attentive reading of the twenty-three chapters 

 into which this publication is divided, it is possible to 

 point out some errors ; but slips cannot be avoided in a 

 work dealing with such a wide range of subjects. It is 

 difficult to follow the author in all his speculations, or to 

 agree with him in all the deductions drawn from his 

 excellent and extensive observations, but such agreement 

 was in no way to be expected in these wide fields of re- 

 search. Almost all the writings and opinions of previous 

 and contemporaneous workers are in some way noticed, 

 and discussed in an appreciative spirit. Mr. Agassiz is 

 in every respect to be congratulated on the completion of 

 this praiseworthy contribution to the growing science of 

 oceanography. So many subjects are presented for dis- 

 cussion and remark that the reviewer is at a loss to know 

 which may with most advantage be touched upon within 

 the limits of a short .notice. An attempt may at all 

 events be made to point out the arrangement of the work 

 and the nature of the varied investigations treated of in 

 the several chapters. 



An introduction gives a brief sketch of the cruises of the 

 Blake, the extent of the work undertaken, and indicates 

 the localities in which these were conducted. Acknow- 

 ledgment is duly recorded for the assistance obtained from 

 naturalists in all parts of the world in working out the 

 Vol. XL.— No. 1033. 



results of the dredgings. By arrangement the specimens 

 were as far as possible sent to the same specialists as 

 were engaged in describing the Challenger collections. 



The first chapter deals with the equipment of the ship, 

 which has already been made known through Captain 

 Sigsbee's publication. Mr. Agassiz, from his engineering 

 training in the copper mines of the West, was able to 

 render very valuable assistance in modifying the apparatus 

 for deep-sea work. To him we owe the introduction of 

 wire dredging rope, improvements in the trawl, tow- net, 

 and other apparatus. The use of tangles on rocky 

 ground was very successful, as it was when used in similar 

 places by the Challenger. The tow-net for intermediate 

 depths is ingenious, but the experiments with it are in no 

 way sufficient to prove that no living animals are to be 

 found at intermediate depths, as is sometimes asserted. 

 The Challenger experiments clearly showed that when 

 tow-nets were dragged for considerable distances at depths 

 of 1000 and 500 fathoms, they always contained animals 

 (Challengerida; and other Radiolarians and fishes, &c.) 

 never taken in the nets dragged down to 100 fathoms 

 from the surface. While the great development of life in 

 the ocean is in the surface and sub-surface waters, where 

 Algae abound, and at and near the bottom, where the 

 organic matters are settling on the mud or ooze, yet it 

 appears to me that the Challenger has also shown that 

 there is no intermediate lifeless region. 



A short chapter gives a fair and impartial historical sketch 

 of deep-sea work, with special reference to the work off the 

 American coast ; and a longer chapter gives avery complete 

 account of the origin, development, and present condition 

 of the Florida reefs — the most thorough account of a 

 series of coral reefs to be found in the literature of the 

 subject. Mr. Agassiz successfully explains the pheno- 

 mena without calling in subsidence, indeed, he found 

 Mr. Darwin's theory quite inappHcable. He rightly 

 places stress on the vigorous growth of the reefs in all 

 situations where they are bathed by currents coming 

 directly from the ocean, and traces this vigorous growth 

 to the abundant pelagic food brought to the reef-form- 

 ing corals by these oceanic currents. He also dwells 

 on the formation of submarine banks by the dead 

 shells of these pelagic and other marine organisms. 

 Speaking of the Pacific, he says : " It is difficult to 

 account for the great depth of some of the lagoons— 40 

 fathoms — on any other theory than that of subsidence." 

 It appears to me that these depths are only found in 

 very extensive atolls and barrier reefs, and that marine 

 animals, other than the ordinary reef-building species, 

 can build up submerged banks from much greater depths 

 than 40 fathoms. Buchanan, on such a bank in the 

 Atlantic, found LophoJielia prolifera growing in large 

 quantities, together with Polyzoa, Crinoids, and other 

 hme-secreting organisms. Besides, in the central parts 

 of the lagoon of completely formed atolls, like Collo- 

 mandu or Suadiva atolls, the solution of lime by the 

 sea-water probably exceeds in quantity that secreted by 

 organisms, and this process would of itself result in a 

 deepening of the lagoon. 



The topography of the Caribbean Sea, Gulf of Mexico, 

 and eastern coasts of North America are illustrated by 

 the admirable hydrographic charts of the Coast Survey, 

 With a thorough knowledge of the various basins, their 



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