16 



SCIENCE. 



[Vol. VI., No. 126. 



cent work before us, with its companion vol- 

 umes, is satisfactory testimony. 



As is natural, the introductory chapters have 

 something of an historical nature, apart from 

 the narrative of the voyage itself; and the 

 progress of deep-sea research is summarized, 

 though without pretensions to monographic 

 completeness. The remarkable results ob- 

 tained by Sir John Eoss, and his foreshadow- 

 ing of many modern methods, are deservedly 

 praised ; and there is no doubt he was half a 

 century beyond his contemporaries and many 

 of his successors. The vessel, her fittings, 

 and the methods of observation adopted, the 

 instrumental devices provided for the regular 

 work, and those suggested by experience, are 

 described and figured in detail. It is known 

 that the work of the Challenger was done with 

 hempen lines, — the method in common use at 

 the time she went to sea, — though wire was 

 adopted shortl}^ afterward. Bearing this in 

 mind, it is easy to note a touch of official con- 

 servatism in the statement (p. 71), that '^ for 

 purposes of deep-sea investigation, however, 

 which includes actual sounding as only one of 

 its items, good hemp sounding-line is still in- 

 dispensable." The errors inevitable to the 

 use of hemp, in all water not absolutely motion- 

 less from top to bottom, are sufficient to decide 

 in favor of its rejection. These errors in the 

 case of the Challenger sounding-work off the 

 coast of the United States, where tested by 

 the U. S. nav}^, are believed in some instances 

 to reach more than two hundred fathoms, and 

 are always liable to be as great when hemp is 

 used. This is no reflection upon their work, 

 which was unquestionably as good as their 

 outfit permitted ; but it forms an irrefragable 

 argument against the use of rope, when a more 

 accurate method is available. 



Without attempting to go into detail for par- 

 ticular localities, it is worth while to trace the 

 general physical features of the sea-bed, as 

 developed by the Challenger work, and enlarged 

 and confirmed b}^ other expeditions, as repre- 

 sented by the charts accompanying this volume. 

 These would have been still better, had the 

 localities of supplementary information been 

 indicated ; for the hypothetical part, neces- 

 sarily large, would thus have been much dimin- 

 ished for the casual inspector. It is pretty 

 well determined, however, that the Atlantic is 

 divided b}' submarine ridges into three diff'erent 

 basins. These ridges, and the deeps they sep- 

 arate, are of singular conformation. From the 

 southern part of Africa a ridge extends south- 

 westerly to mid-ocean. From this a ridge ex- 

 tends a short distance westward, and another 



nearly due north to the equator. Sheering oflf 

 from the African coast, with which it never- 

 theless preserves a curious parallelism, it ex- 

 tends north-westward, throwing off" a spur 

 toward French Guiana, which closes the north- 

 ern rim of the south-western Atlantic basin. 

 The central deep of this basin is supposed to 

 lie about seven hundred miles off the moun- 

 tainous coast-region of Brazil, from Cape 

 Roque to the Rio Doce. From the last-men- 

 tioned portion of the ridge, it extends north- 

 ward and eastward, widening as it goes, rising 

 above the sea at the Azores, and finally joining 

 the great arctic plateau, nearly in mid-ocean, 

 at about the latitude of Paris. The north- 

 western basin has its greatest deep north from, 

 but close to, the Windward Islands. Here the 

 coast-survey has since found the deepest water 

 known in the North Atlantic. The eastern 

 basin, of irregular and elongated form, has 

 two deeps, — one westward from the Cape 

 Verde Islands, the other north-eastward from 

 St. Helena. There is a smaller depression 

 just south from Cape Palmas. 



In the southern ocean the antarctic plateau 

 extends nearty to Africa, in latitude 40° south, 

 and reaches New Zealand and Patagonia by 

 narrow isthmuses. The vast area of the Pacific 

 is less known and less markedly divided. Its 

 greatest deep lies along the Kurile Islands, 

 is very narrow, and is doubtless the deepest 

 depression existing in any ocean. Apart from 

 the Polynesian area, its most conspicuous ele- 

 vation extends sickle-shaped from the coast 

 of South America in latitude 40° south, to the 

 meridian of 120° west. Otherwise the eastern 

 portion of the Pacific presents an astonishing 

 uniformit3\ 



JAGNAUX 'S TRAITE DE MINERALOGIE. 



It would not seem to be an unreasonable 

 demand, that a volume of nine hundred pages, 

 and bearing the date of 1885, should contain 

 enough fresh and valuable matter to make its 

 stud}^ thoroughly profitable to those specially 

 interested in the subject of which it treats ; 

 but this will hardly be found to be true with 

 this new Mineralogy of Jagnaux. The reader 

 who expects to find the value of this large 

 volume in proportion to its size will be much 

 disappointed. The task which the author has 

 set for himself — that is, the preparation of 

 a work which shall give scientific descriptions 

 of all important mineral species, and at the 

 same time develop all the apphcations of 



Traite de mineralogie appUquee aux arts, a Vinduatrie, au 

 commerce et a V agriculture, etc. Par Raoul Jagnaux. Paris, 

 Doin, 1885. 883 p., 468 ligs. 8o. 



