February 20, 19 13] 



NATURE 



669 



the task of determining their nature and origin is 

 one that is almost beyond the range of ordinary 

 analytical methods. In addition to the natural 

 oils and fats it is necessary now to take into 

 account the artificial products obtained by reducing 

 them by hydrogen in presence of nickel; although 

 these are only rarely mentioned, their preparation 

 has already become an extremely important in- 

 dustry, which has grown to maturity at a very 

 rapid rate and almost unobserved by the general 

 public. 



The " Handbook " of Messrs. Bolton & Revis 

 has the merit of dealing with the examination of 

 oils and fats exclusively from the point of view of 

 their utility as food products. They have there- 

 fore been able to treat this branch of the subject 

 with great thoroughness in a book of very modest 

 dimensions. As they have had many years of ex- 

 perience in carrying out the tests which they 

 describe, their conclusions are entitled to be re- 

 ceived with respect and regarded as authoritative. 

 This statement applies not only to their selection 

 of the tests which are most suitable, but also to 

 the rejection of others which are less suitable or 

 even seriously faulty ; as they remark in the 

 preface, " omission of a method may often be better 

 evidence of the knowledge of it than its presenta- 

 tion." The book is well illustrated and attractively 

 printed ; its utility will not be diminished by the 

 fact that it has not passed through the hands of 

 a literary editor, and bears the impress of the 

 laboratory rather than of the classroom or the 

 study. 



(2) Dr. Ditmar's monograph on rubber is char- 

 acterised by the scientific character of its treatment 

 of a technical subject. At the head of the preface 

 the statement is set out that "The essence of a 

 colloid is instability : for this reason life is linked 

 to the colloidal state. Uai'Ta /jct," The view of 

 Heraclitus that " Everything is in a state of flux " 

 is particularly applicable to the colloidal state, and 

 has much to do with the inherent quality of 

 ■'perishing," which is so serious a limitation to 

 the usefulness of rubber. The importance of this 

 "perishing" is shown by the fact that the author, 

 in his chapter on the "Regeneration of Rubber," 

 gives a list of nearly 200 patents, nearly all of 

 which have been taken out during the last ten 

 years. 



.A.ttention is directed to the great imix)rtance of 

 ihe coagulation processes as affecting the nature 

 of the product. In the case of synthetic rubber 

 the aim must be to secure a highly polymerised 

 product : the polymerised isoprene of the Elber- 

 feld works possesses these qualities, but the poly- 

 merised butadiene resembles glue and can only 

 be used as' a "blender" or adulterant. It is im- 

 NO. 2 2 60- VOL. QOl 



possible in a brief notice to discuss the vast amount 

 of valuable information that has been brought 

 together in this monograph, but it may be com- 

 mended without reservation to the attention of all 

 those who are interested in rubber, either as a 

 technical product or as material for the study of 

 colloid chemistry. 



(3) Dr. Mellor's "Modern Inorganic Chem- 

 istry " is one of the most original of the text-books 

 that have been published in recent years. Its very 

 originality will probably limit its usefulness as a 

 text-book for beginners, who would probably be 

 well advised to acquire the rudiments of their 

 knowledge from some more conventional source. 

 But for a student who has already acquired a 

 sound knowledge of inorganic' chemistry, and is 

 wondering in what way he may best add to it, 

 it would be difficult to suggest a volume more 

 calculated to impart new ideas and increased in- 

 formation than Dr. Mellor's book. It would serve 

 admirably as a text-book of inorganic chemistry 

 to cover the gap between the requirements of an 

 intermediate and final B.Sc. examination. 



The jour crystalline forms of sulphur have at 

 last been able to secure equal recognition in a 

 text-book, and in the course of two pages the 

 modern views of the composition of steel are 

 effectively summarised. Little monographs such 

 as these, embodying the results of recent re- 

 searches, are of frequent occurrence and cover a 

 very wide range of topics. On the other hand, the 

 historical aspects of chemistry receive full recog- 

 nition, nearly every statement of importance being 

 accompanied by the name of the author who first 

 discovered the facts and the date of the discovery. 



(4) It is a matter of interest to receive a text- 

 book of chemistry bearing on its title-page the 

 names of a science master and an "examiner in 

 education." The book that they have compiled is 

 as a whole very logical and satisfactory, and in- 

 cludes incidental references to several phenomena 

 which can be described in simple terms, but which 

 have not previously found their way into ele- 

 mentary text-books. Amongst these the distilla- 

 tion of petroleum, the manufacture of linoleum, 

 and the liquid-air process for separating oxygen 

 may be mentioned. 



The authors appear to be unaware of the his- 

 torical aspects of their subject. There is really 

 no need to use such a term as " soda gas " when 

 Black's name of "fixed air" is available as a 

 description of the gas which does not introduce 

 prematurely to the student a statement of the pres- 

 ence of carbon in it. The authors have also been 

 obliged to confess the illogical character of their 

 action in describing the gas as "carbon dioxide" 

 in chapter xvi. when they are unable even to 



