April io, 19 13] 



NATURE 



expressed 



ordinary chemical 



be accurately 

 English. 



The next chapter contains much interesting- 

 matter concerning- the origin and chemical 

 nature of mineral oils, and the principles under- 

 lying the commercial methods of oil-refining. 

 Under the heading of saponifiable oils and fats a 

 very judicious selection has been made of the 

 most important members of a very large group of 

 substances derived from both animal and vege- 

 table sources. The analytical methods employed 

 in testing these materials are briefly described, 

 and in several instances illustrations are given of 

 the apparatus employed. The industrial applica- 

 tions of fats and oils are classified, special atten- 

 tion being paid to the various commercial 

 processes of hydrolysis, and to the purification of 

 the higher fatty acids by distillation in super- 

 heated steam. 



In the section devoted to soap and candle 

 manufacture the author shows how the phase 

 rule and recent discoveries in colloid chemistry can 

 be applied to elucidate the reactions of the "soap- 

 pan. Reference is also made to the part played 

 by adsorption complexes in the detergent action 

 of soap. 



Looking to the future, the production of petrol- 

 eum motor spirit by the thermal decomposition 

 of heavier hydrocarbons is suggested as 

 jnising problem for research. 



(2) The present volume is one of a series of 

 "Readable Books in Natural Knowledge," the 

 author's theme being the usefulness of the 

 chemist to the community. It is to be hoped 

 that this work will assist in dispelling the de- 

 plorable ignorance still existing in the minds of 

 many of the British public in regard to the 

 nature and scope of the chemist's activities. 

 Although on the Continent the difference between 

 "chemiker" and "apotheker" or between 

 "chimiste " and "pharmacien" is well under- 

 stood, in the United Kingdom the chemist is still 

 usually assumed to be a person who of necessity 

 trades behind a window ornamented with large 

 bottles containing various coloured solutions. 



After referring to the work of the pioneers of 

 modern chemistry, the subject of combustion is 

 discussed with the object of showing that this 

 typical chemical change includes not only the burn- 

 ing of ordinary combustibles, but also such pheno- 

 mena as fermentation, the rusting of metals, and 

 the drying of certain oils. In this connection alone 

 the chemist may with advantage be consulted by 

 the farmer, the coal exporter, the cloth manufac- 

 turer and other industrial workers in regard to 

 difficulties arising in the ordinary course of their 

 avocations. 



NO. 2267, VOL. 91] 



pro- 



The irrational mode of domestic heating with 

 smoky coal leads the author to recommend 

 "coalite " (semi-coke) or gas-fires., A human note 

 is touched by the remark that the latter are 

 regarded with disfavour because they cannot be 

 poked and nothing can be thrown into them. A 

 more serious objection to gas-fires is suggested 

 under the heading of secondary fuels, namely, the 

 grave risk of poisoning arising from faulty gas- 

 fitting and the high percentage of poisonous 

 carbon monoxide present in modern illuminating 

 gas. 



The achievements of inorganic synthetic 

 chemistry receive adequate attention. It is 

 pointed out that by a curious coincidence the year 

 1828 witnessed not only the synthesis of urea, 

 but also the successful manufacture of artificial 

 ultramarine. The natural pigment from lapis 

 lazuli, which was once worth its weight in gold, 

 is now replaced by the synthetic product sold at 

 less than thirty shillings a hundredweight. 



The admirable detective work performed by the 

 analytical chemist in bringing to justice the sophis- 

 ticator of* food is noted with the appreciation which 

 this public service deserves. 



(3) This volume, which forms one of a com- 

 prehensive series of scientific pocket-books, gives 

 a summary of the manufacture of nitrocellulose 

 and its conversion into celluloid by means of 

 camphor and other adjuvants. The inflam- 

 mability of this material, which is now employed 

 on an enormous scale in the production of cinema- 

 tograph films, has led to many processes having 

 for their object the preparation of non-inflammable 

 celluloid substitutes. Viscose (an alkaline solu- 

 tion of viscoid) is now manufactured from wood 

 pulp, soda ley, and carbon bisulphide. Aceto- 

 cellulose, the product of the acetylation of cellu- 

 lose, has been placed on a commercial basis in 

 the Elberfeld colour works, after seven years of 

 research. Galalite, prepared by precipitating 

 casein with formaldehyde, can be obtained in a 

 transparent condition by first removing mineral 

 salts from the casein by successive treatment with 

 alkalis and acids. The condensation products of 

 phenol and formaldehyde, when indurated to the 

 desired extent by heating under pressure, give 

 rise to the valuable plastic material "baekelite." 

 The work is of interest as showing the extent to 

 which the celluloid industry has developed in 

 France. 



(4) Although this guide to qualitative analysis 

 contains a certain amount of useful information, 

 the matter is not arranged in such a way that 

 it can be readily followed. The group reactions, 

 for example, would be more easily grasped it 

 given in tabular form. Very little attempt is 



