3i6 



NATURE 



{Feb. 



2, I 



close to many tropical shores off which the wind blows 

 steadily. For instance, near Cape Guardafui, when the 

 south-west monsoon blows off shore, cold water is found 

 near the land, but when the north-east monsoon blows on 

 shore nothing but warm water can be discovered. The 

 theory is that an off-shore wind blows, or rubs, the 

 sun-heated surface water to leeward, and that the proper 

 level of the sea is maintained by cold water welling up 

 from below. Mr. J. Murray, of the Challenger, has dis- 

 covered a similar effect in the long, narrow, deep waters 

 of Loch Ness. With a south-west wind the coldest 

 water is at the south-west end of the lake, but when the 

 wind changes to north-east the lowest temperature is 

 found at the north-east extremity. 



The remainder of the work is taken up by a descrip- 

 tion of the currents of the ocean. The theory, of course, 

 is fully given, and we may note that the author uses 

 Ferrel's formula for the deflection of a moving particle to 

 the right, through the influence of the earth's rotation, 

 which has been accepted in every country except England. 

 The long detail of the currents in different oceans of 

 course contains little novelty, but is illustrated by an 

 excellent map in blue and red of the direction and 

 velocity of these well-known cold and hot streams. 



Both of these volumes are to a certain extent uncritical 

 compilations, for the results of various experiments and 

 observations are merely recorded, without any comment 

 on the varying quality of the work. We have already 

 commented on the absence of maps ; and the instru- 

 ments used in oceanic research might well have been 

 much more copiously illustrated. Still this work is a 

 most valuable addition to the literature of the subject, 

 and we wish that it could be translated into English. 



There is no text-book of the subject in England, 

 beyond School-Board primers, except the work of Maury ; 

 and this, in spite of a fascinating style, is too fanciful, and 

 too much out of date, to be of any use. 



Though the volumes now under review can never be 

 popular in the ordinary sense of the word, still they 

 would be invaluable to scientific men and others, who 

 though not specialists wish to study in a compact and 

 available form the present state of knowledge of one 

 of the most interesting branches of modern research, 



Ralph Abercromby. 



BULLETIN OF THE UNITED STATES FISH 

 COMMISSION. 



Bulletin of the United States Fish Commission. Vol; VI., 

 for 1886. (Washington : Government Printing Office, 

 1887.) 

 nPHE immense number of short articles in this volume 



-L are as usual classified in a topical synopsis of the 

 contents. The largest class is that of articles concerning 

 the fisheries, the next in size contains those concerning 

 aquiculture, the next those concerning natural history, and 

 there are two other classes headed U.S. Fish Commission 



—General, and Miscellaneous. Of the biological articles 

 Mr. John A. Ryder contributes only three, and the reader 

 regrets there are not more from his hand. One is on the 

 early development of the toad-fish, Batrachus tau, whose 

 eggs arel described as adherent, being fixed to the under 

 surface of submerged boulders. The young toad-fish 



have this unique peculiarity, that when the egg-membrane 

 bursts they are not set free but the lower surface of the 

 yolk-sac remains firmly fixed to the adherent portion of 

 the membrane, and this adhesion continues until the yolk- 

 sac has become almost entirely intra-abdominal. The 

 second of Mr. Ryder's papers is on the cleavage of the 

 blasto-disk in the ovum of Raja erinacea ; and the third 

 on the intra-ovarian gestation of the viviparous Sebastes 

 marinus : this last is based upon the examination of a 

 gravid specimen obtained by the Albatross. 



The few articles on the reproduction and generative 

 organs of eels are of little value, as the information 

 contained in them is not up to date. One, for instance, 

 is a translation of a paper by Prof. Pavesi, published in 

 1880, and therefore of course treating as probabilities 

 propositions concerning the testes which were proved in 

 1881 by Otto Hermes. 



Among the aquicultural articles there are a great many 

 on the shad-hatching work of the Commission, most of 

 them detailing statistics of the operations of 1886. In 

 one of these Marshall McDonald announces that for the 

 entire period of the Commission's work up to and including 

 1882, 200,000,000 of young shad were produced, while 

 for 1886 alone the total was 90,000,000, and this last 

 number was fifteen times as great as the number of adult 

 shad captured for market in one season. In another 

 report by the same writer we find that the cost of pro- 

 duction of shad-fry was $127 •66, or about ^{^25, per million. 

 The exact effect of the artificial production of shad-fry on 

 the supply of the adult fish is not estimated, but in one 

 place we find that the catch in the Potomac was much 

 larger in 1886 than in 1885 ; and in another that in 

 Connecticut pollutions and sewage are diminishing tlie 

 number of shad in the rivers. 



Evidence is given that shad are now fairly abundant 

 on the whole coast of California, apparently from plant- 

 ings in the River Sacramento, but no regular run of shad 

 seems to have been produced in that river ; and we find 

 statistics of plantings in 1886, in the Columbia and 

 Colorado, from which a better result is expected. But of 

 course thie Bulletin is not the place to look for a connected 

 and logical discussion of the operations carried out and 

 their results. The publication contains occasional notes 

 and statistics which are interesting to those who are 

 familiar with the matters to which they belong, and which 

 place on record facts which form materials for a connected 

 study. 



Of the very large amount of information comprised 

 under the heading Fisheries, we cannot say more here 

 than that it includes details and statistics not only of 

 American fisheries but of those of all parts of the world. 



OUR BOOK SHELF. 



Flour Manufacture : a Treatise on Milling Science and 

 Practice. By Friedrich Kick ; translated by H. H. P. 

 Powles. (London: Crosby Lockwood and Son, 1888.) 



The art of flour-milling, which of late years has under- 

 gone changes in its method of the most marked character, 

 has at no time been productive of anything like a copious 

 technology ; and, in the attempt to supply this deficiency, 

 it was natural that Mr. Powles should turn his regard 

 towards Austria, where the manufacture of flour had 

 engaged the attention of scientific experts long before the 



