304 



NA TURE 



[January 13, 19 10 



the basis of the author's conception of the elements, 

 an eleiTient being a substance which cannot be trans- 

 formed into another non-hylotropic substance within 

 the entire range of attainable energy influences. By 

 energy influences are understood any processes car- 

 ried out without the actual addition of other sub- 

 stances. This statement is, however, scarcely ade- 

 quate for the sifting out of the chemical elements. It 

 may have been the case before the discovery of the 

 radio-active substances, but the spontaneous disinte- 

 gration of these obviously represents a non-h3'lotropic 

 change, and as a consequence these elements do not 

 fall into line. 



The discussion of the laws of chemical combination, 

 of colligative properties, and of catalysers is clear 

 and lucid, but does not present anv striking noveltv. 



In the chapter on ions the nature of a salt is ex- 

 amined. To the many definitions of this particular 

 type of chemical individual which have been given, 

 the author adds a new one. According to Ostwald, 

 a salt is a substance which has the properties of a 

 pure substance in the undissolved condition, whilst 

 it exhibits the properties of two different substances 

 when in solution. If in all solvents all salts are 

 ionised or dissociated, this definition is probably suffi- 

 cient to describe this group of bodies. It is, however, 

 doubtful whether any practical test, based on the de- 

 finition, could be actually applied to determine whether 

 any particular substance is a salt or not. 



In spite of the fact that we may not agree with 

 the author's choice of fundamental concepts, and 

 that certain results to which he is led are not in accord- 

 ance with actual facts, it cannot be denied that the 

 general treatment of the subject is profoundly in- 

 teresting, and that the analysis of facts and ideas is 

 conducted with great ingenuity. The subtitle cannot 

 be taken very seriously, for it is too much to expect 

 that the contents of the book can be digested by the 

 future chemist prior to his study of the orthodox text- 

 book. It should, however, appeal to the more mature 

 student, to whom it is confidently recommended. 



H. M. D. 



OCEANOGRAPHY IX THE NORTH ATLANTIC. 

 Scientific and Biological Researches in. the North 



Atlantic, conducted by the Author on his Yachts 



" The Walu'in " and " The Silver Belle." By Dr. R. 



Norris Wolfenden. Pp. vii -1-234. (London : Reb- 



man, Ltd., 1909.) Price 7,9. 6d. net. 

 N this w-ork Dr. Wolfenden gives an account of the 

 hydrographic and biological researches carried 

 out on board his yachts, the ]Valii.'in and Silver Belle, 

 from iSgg to 1907. The investigations, begun in the 

 Fseroe Channel with the Wakvin (36 tons), which was 

 replaced in 1902 by the Silver Belle (130 tons), were 

 afterwards extended to the Azores and Gibraltar. 



.Apart from the observations actually recorded, this 

 account is valuable as showing what a large amount 

 of useful scientific work may be carried out on board 

 a sailing yacht of moderate size, the cost of the addi- 

 tional gear necessary being only a small proportion of 

 the original outlay. It will probably be a surprise 

 to many to learn that from a sailing yacht of 130 tons 

 NO. 209S, VOL. 82] 



soundings, physical observations, and tow-nettings 

 may be taken at a depth of 1500 fathoms with com- 

 parative ease and certainty. 



The first sixty pages are occupied by a summary 

 of the various cruises, and give some idea of the 

 inclement weather which may be expected in the 

 North .-Vtlantic even in summer. The work was carried 

 on in spite of considerable difficulties and hardships, 

 and the amount accomplished is very much to the 

 credit of the Silver Belle and her crew of Shetlanders. 

 .\n accompanying chart shows the positions of the 

 stations on each cruise, and also the contour lines of 

 depth of 100 and 2000 fathoms. The loo-fathom line 

 is, however, erroneously drawn outside the Porcupine 

 Bank, off the west coast of Ireland, instead of passing 

 between it and the mainland. 



Following the narrative of the cruises. Dr. Wolfen- 

 den gives the benefit of his lengthy and somewhat 

 costly experience in the choice and manipulation of 

 fishing engines and physical apparatus. It appears 

 that the taking of water samples and temperatures in 

 deep water can be worked for the most part without 

 mishap even in rough weather, but that a heav)" sea 

 prevents the satisfactory use of closing plankton nets. 

 The chief source of danger is the rolling of the ship, 

 which, by slackening the wire, causes it to "kink," 

 and thus prevents the descent of the opening and 

 closing messengers, if it does not result in the loss of 

 both wire and net. 



The greater part of the book is occupied by an 

 account, by Dr. H. N. Dickson, of the hydrography 

 of the various cruises. Except in the case of the Fasroe 

 Channel, which is dealt with in considerable detail, 

 Dr. Dickson contents himself with pointing out the 

 general conditions of salinity and temperature prevail- 

 ing over the regions investigated, deferring the further 

 discussion of the results until a longer series of 

 observations has been accumulated. He directs atten- 

 tion, however, to the effect of the highly saline water 

 of the Mediterranean flowing outwards through the 

 Straits of Gibraltar. The section plotted on p. 161 

 shows clearly how the denser water, pouring over the 

 sill as if over the edge of a waterfall, sinks to a depth 

 of about 600 fathoms, and at that level streams out 

 horizontally in a layer more saline than that above or 

 below it. The influence of this water w'as noticeable 

 in the high salinities at intermediate depths found off 

 the coast of Portugal in 1904 and 1905, and it will 

 be interesting to learn, when the results are published, 

 whether the plankton taken on these occasions con- 

 tains any indication of a Mediterranean origin. Dr. 

 Dickson alludes to the probability of this water reach- 

 ing the English Channel, and emphasises the import- 

 ance of continued observation. Other points of interest 

 dealt with are the differences of salinity and tempera- 

 ture on the north and south sides of the Porcupine; 

 bank, and the accumulation of evidence to show the 

 existence of a cold bottom current flowing southwards 

 over the Wyville-Thomson ridge. A complete series of 

 sections and full tables of the salinities, temperatures, 

 and meteorological observations on each station are 

 given, but a serious omission is the absence from the 

 tables of a column for the depth of water, which can 



