786 



SCIENCE. 



[N. S. Vol. XI. No. 281. 



' ' to classes of young men who intend to be- 

 come farmers, and who desire information that 

 will beof assistance to them in their profession." 

 It aims to give "the principles of chemistry 

 which have a bearing upon the conservation of 

 soil fertility and the economic use of manures.'' 

 The author has performed his task in a very 

 satisfactory manner. He has treated the sub- 

 ject logically and sj'stematically, giving first 

 the scientific principles, and then laying stress 

 on their practical application, but not to such 

 a degree as to make the work a hand-book in- 

 stead of a text-book. The historical develop- 

 ment of the subject has not been neglected, 

 though naturally the treatment has been very 

 condensed. 



Notwithstanding the general excellence of 

 the work, there are certain errors and defects 

 which cannot be overlooked. The language is, 

 at times, too condensed for clearness, as, for 

 example, in the description of the analysis of 

 soils on page 74. The writer has a habit of 

 leaving out the comma in sentences like these, 

 ' that produced from cellulose bodies as saw- 

 dust, ' ' produced by each material as green 

 clover, oat straw.' It is stated on page 42 that 

 " the additional amount of water in the humus 

 soil may cause the soil temperature to be lower 

 than that of the sandy soil. While the humus 

 soil absorbs more heat than the sandy soil, the 

 heat is used up in evaporating water." The 

 heat is used up in warming the water, more 

 than in evaporating it ; the specific heat of soils 

 being from 0.2 to 0.4, as stated in the next 

 paragraph. On page 93 the statement is made 

 that, "the non-nitrogenous compounds as cel- 

 lulose, starch and sugar undergo a fermentation 

 but seem to possess little, if any, power to 

 form humates in the soil." And the third 

 sentence reads, "straw, sawdust and sugar, 

 materials rich in cellulose and other carbohy- 

 drates, yield a humus characteristically rich in 

 carbon and poor in nitrogen." These state- 

 ments appear inconsistent. The table on page 

 94 is not correctly arranged. On page 115 the 

 statement is made, "like the nitrates and 

 nitrites, the ammonium compounds are all solu- 

 ble and hence cannot accumulate in soils which 

 receive an average amount of rainfall." This 

 leaves a false impression, for ammonium com- 



pounds are fixed by soils almost as readily as 

 potash, becoming soluble with difBculty (1 part 

 in 10,000 of water), while the nitrate and nitrites 

 are not fixed, but wash out with great readiness. 

 The fact that ammonium salts are fixed by the 

 soils is not mentioned in the chapter on fixation. 

 This book is, on the whole a very good one ; 

 it is cordially recommended to the attention of 

 all instructors in agricultural chemistry, and, 

 while not written with this end in view, it is 

 recommended to those agricultural chemists who 

 desire to obtain a survey of the rapidly widen- 

 ing field of research relating to soils and ferti- 

 lizers. G. S. FRAPS. 



A Short History of the Progress of Scientific Chem- 

 istry in our oivn Times. By William A. Til- 

 den, D.Sc, F.R.S. Longmans, Green & 

 Co., London, New York, and Bombay. Pp. 

 X + 276. 



The task which Dr. Tilden set before himself 

 in the preparation of this book was to give in 

 broad outline a sketch of the development of 

 chemistry during the period of the Victorian 

 era. The subject has been treated topically 

 rather than chronologically, and the method of 

 treatment chosen is abundantly justified in the 

 result. The topics selected are : Matter and 

 Energy ; The Chemical Elements ; Atomic 

 Weights ; Classification of the Elements ; Val- 

 ency and the linking of Atoms ; Synthetical 

 Chemistry; Stereo-chemistry; Electricity and 

 Chemical Aflinity ; Liquefaction of Gases. An 

 exhaustive historical treatment of these topics 

 does not, of course, lie within the scope of the 

 work. Indeed, its value depends very greatly 

 on the fact that the author has known so well 

 what to select, and because the topics selected 

 have been treated with sufficient fullness to 

 be interesting and intelligible to any one pos- 

 sessing an elementary knowledge of the subject. 

 The book should find a large field of useful- 

 ness. W. A. Notes. 



Outlines of Industrial Chemistry. By Frank 

 Hall Thorp, Ph.D., Instructor in Indus- 

 trial Chemistry in the Massachusetts Institute 

 of Technology. A text-book for students. 

 New Edition revised. New York, The Mac- 

 millan Company. 1899. Pp. xvii + 541. 

 Price, $3.50. 



