October 14, 1920] 



NATURE 



207 



methods of manufacture of fertilisers and only 

 incidentally with their use on the farm, giving 

 simply such information as the ordinary salesman 

 would need. Liberal use is made of the Rotham- 

 sted data, which supply the best demonstrations of 

 the value of the nitrogenous and potassic fer- 

 tilisers and of superphosphate. Cockle Park, 

 Northumberland, gives the best demonstration of 

 the value of basic slag. 



Striking data are shown as to the improvement 

 in the soil effected by the use of fertilisers. Thus 

 at Cockle Park basic slag not only increases the 

 yield of herbage for hay or for grazing, but also 

 leads to an increase in the percentage of nitrogen 

 m the soil — the result of an increased development 

 of clover. .After eleven years' treatment with 

 basic slag the percentage of nitrogen in the soil 

 of Tree Field, Cockle Park, has increased from 

 o 185 per cent, to 0236 per cent., a gain of about 

 850 lb. per acre. Neither sulphate of ammonia 

 nor nitrate of soda brought about an appreciable 

 increase in nitrogen content. 



.\ good but short description is given of the 

 deposits of nitrate of soda in Chile, and also of 

 the deposits of nitrate of potash in India. The 

 manufacture of sulphate of ammonia is described, 

 and the account brought up to date by refer- 

 ence to some of the more recent processes. 

 In view of the importance of this industry we 

 should have liked to see a fuller classification of 

 methods and descriptions of typical direct, semi- 

 direct, and indirect processes : the average student 

 of agricultural chemistry has usually no access to 

 modern books in which these are described. An 

 account is given of the Haber process, which will 

 prove of interest now that the method is to be 

 worked in this country. 



Superphosphate naturally occupies considerable 

 space, and a useful table shows the composition 

 of the natural phosphates used as raw material. 

 Here, too (as in the case of sulphate of ammonia), 

 one would have liked more information from the 

 works : more might have been told of the different 

 types of dens in use in this country and, before 

 the war, in Belgium. The introduction of elec- 

 trical power has resulted in certain modifications 

 in methods. 



In discussing compound fertilisers no reference 

 is made to the "base" — an organic material often 

 acidulated, or a seed meal — used to obtain proper 

 condition. 



From the laboratory side, however, the book is 

 very good, as would have been expected from the 

 author, and as it has no Knglish competitor a 

 good reception should be assured. It contains 

 much useful information that the student could 

 not readily obtain elsewhere. 

 NO. 2659, VOL. 106] 



Lectures on Folk-lore. 



Psychology and FoJk-lorc. By Dr. R. R. Marett. 

 Pp. ixH-275. (London: Methuen and Co., 

 Ltd., 1920.) Price 7^. 6d. net. 



CONTROVERSY is commonly interesting, if 

 only for the fact that it appeals to a man's 

 pugnacious instincts ; and most readers like to be 

 invited to take sides. Eight of the eleven papers 

 in this book were originally lectures, and in most 

 of them Dr. Marett argues vigorously against 

 what he regards as a lifeless manner of attacking 

 the problems of folk-lore. He states his position 

 in the first paper, and stands by it staunchly all 

 through the volume. To him it is perfectly clear 

 that every scrap of folk material is ultimately due 

 to the more or less primitive reactions of the in- 

 dividual mind. Now nobody can understand 

 either the productions or the modes of operation 

 of the human spirit, he believes, by merely look- 

 ing at them from the outside. The prime problem 

 of all folk-lore is to enter into a man's thoughts, 

 fancies, and emotions when he is confronted by 

 certain definable situations. But simply to study 

 objectively the changes which folk material has 

 undergone in the course of its history is only to 

 gather together a lot of dry bones. The psycholo- 

 gist is needed to put flesh on them, and to breathe 

 into them the breath of life. Dr. \V. H. R. 

 Rivers is thereupon, in the most pleasant manner 

 possible, held up as an awful example of the soul- 

 less sociologist. 



As to this some comments may be made. First, 

 bones are needed to make a man, after all. 

 Secondly, the distinction which Dr. Rivers has 

 made, and quite consistently observed, be- 

 tween psychology and sociology is one framed 

 specifically in the interests of method and of clear 

 definition. It is preposterous even to hint that 

 Dr. Rivers has urged that an objective, socio- 

 logical study can cover anything like all of the 

 ground of interest of folk-lore. He has shown, 

 both by his words and also by his example, that 

 the studies of psychology and sociology must pro- 

 ceed side by side. But he has all along been con- 

 cerned to utter a much-needed protest against the 

 fashion of mixing up psychological, sociological, 

 biological, and ethical modes of explanation in the 

 customary haphazard manner. 



It is very interesting to consider precisely what, 

 in Dr. Marett's opinion, psychology really has to 

 say at present concerning the problems he dis- 

 cusses. The main subjects of his consideration 

 are : War and Savagery ; Primitive Values ; The 

 Psychology of Culture Contact; The Transvalua- 

 tion of Culture ; Origin and Validity in Religion ; 

 Magic or Religion ; The Primitive Medicine Man ; 



