458 



NA TURE 



[March i6, 1905 



of the book is increased by this course, and the 

 subject made more human. 



In conclusion, it is perhaps sufficient to say that 

 the treatment is marlted throughout by the author's 

 vvell-lvnown and admirable lucidity of style. Take, 

 for example, the last paragraph in the book 

 discussing the result which follows from the fact 

 that as an extreme case for the green thallium light 

 the periods of 88 per cent, of the vibrating molecules 

 are identical within about one part in two millions. 



" If you had a great many clocks, and found that 

 taking their average rate to be correct, not more 

 than one in eight would be wrong by a second in 

 twenty-three days, that would represent the maximum 

 amount of variation which one interpretation of the 

 experiment allows us to admit in the case of 

 molecular vibrations. But would any maker under- 

 take to supply you with a number of clocks satisfying 

 that test? If, further, it is considered that the limits 

 we have chosen for the possible variations of 

 molecular vibrations are far too great, we see that 

 though Sir John Herschel's saying that atoms 

 possess the essential character of manufactured 

 articles is still correct, yet no manufactured article 

 approaches in accuracy of execution the exactitude 

 of atomic construction. \\"c may conclude with 

 iMaxwell that ' Each molecule therefore throughout 

 the universe bears impressed on it the stamp of a 

 metric system as distinctly as does the metre of the 

 archives at Paris or the double royal cubit of the 

 Temple at Karnac. ' " 



TECHNICAL ANALYSIS. 

 Manual of Chemical Analysis. By E. Prost, D.Sc. 



Translated by J. C. Smith, B.Sc. Pp. iv + 300. 



(London : Maclaren and Sons, 1904.) Price 12s. 6d. 



net. 

 Techno-Chemical .Analysis. By Dr. G. Lunge. 



Translated by .\. I. Cohn. Pp. vi+136. (New 



York : Wiley and Sons ; London : Chapman and 



Hall, Ltd., 1905.) Price 45. 6d. net. 



DR. PROST 'S manual contains a number of 

 selected methods dealing more particularly with 

 mineral and metal analysis which have been compiled, 

 so the preface states, for the use of the " industrial 

 chemist," and which the author assures us are the 

 result of his own experience or that of specialists 

 with whom he is in touch. 



The analysis of mineral products — silicates, phos- 

 phates, clays, cements, iron and iron ores, and the 

 assaying of lead, silver, gold, &c., have been so 

 fully elaborated that no analyst deserving the name 

 would be satisfied without knowing the latest im- 

 provements in the methods connected with his own 

 industry. A chemist in an iron works, for example, 

 wants all the information he can obtain from the 

 specialist who has made a minute study of iron and 

 steel analysis, including the character of etched 

 surfaces, and through whose hands a large variety 

 of specimens have passed The same, of course, 

 applies to raw materials and finished products of other 

 manufactures. The works analyst is not a student, 

 and though he may wish to be informed on analysis 

 in general, it is not essential to his business. 



Does Dr. Frost's book as a whole fulfil its 

 promise? Whilst there is no doubt that many of the 

 NO. 1846, VOL. 7 I j 



methods answer to the description given in the 

 preface, and will be found serviceable to the works 

 analyst, it must be confessed there are also many 

 others which fall short of it. In too many instances 

 there is a lack of descriptive detail, an absence of 

 reference to recent improvements, and the omission 

 of recognised and standard methods. The common 

 fault of this class of book is to be too discursive ; 

 to cover too much ground. The small treatise on one 

 subject by an expert like Blair or Ledebur on iron 

 and steel analysis, Brown on gold and silver assaying. 

 Lunge on the alkali manufacture, is the sort of thing 

 one would like to see multiplied. 



The writer has no wish to deal unfairly with the 

 manual under review. It is not uniform in 

 character, and if the above criticism applies to certain 

 sections, it is also abundantly evident that other 

 portions have been carefully and conscientiously put 

 together by one who possesses a thorough knowledge 

 of his subject. Moreover, the introduction of 

 mechanical tests, which are too frequently overlooked, 

 is a feature deserving mention. The translator's 

 attention should be directed to the mis-spelling of 

 Stanfurt for Stassfurth, p. 41, Vollard for Volhard, 

 p. 106, and Spiegal for Spiegel, p. 206. The illustra- 

 tions suffer very much from the rough surface of the 

 paper. 



The name of Dr. G. Lunge on the title page of any 

 book, and especially one connected with technical 

 analysis, would command a careful perusal and a 

 thoughtful judgment. It must be confessed that in 

 the present case the autlior has not done himself 

 justice. Anyone who purchased the volume in the 

 hope of obtaining practical information on techno- 

 chemical apalysis (the translator's rendering of 

 chemisch-technische L^ntersuchungsmethoden) would, 

 to say the least, be disappointed. 



When it is stated that in 128 small oetav-o pages, 

 in addition to " general operations," and gas, water, 

 and fuel analj'sis, the analysis of about eighty 

 technical inorganic and organic products is described, 

 further comment seems superfluous. The subject of 

 glycerine, which comes under the section of soap, 

 may be taken as a specimen of the method of 

 analytical treatment. 



" Glycerine is found in large quantity only in toilet 

 soaps. The method of determining it is given here, 

 because it must be examined by itself as an individual 

 commercial article, and the glycerine yield of raw- 

 fats in the manufacture of stearin must also be 

 determined. The determination is effected either by 

 oxidation with potassium-permanganate solution in 

 alkaline solution, precipitating the oxalic acid formed 

 as a lime salt, and titrating the latter, or by oxidation 

 with normal potassium-dichromate solution, with the 

 addition of an excess of ferrous sulphate solution of 

 known effective value, and tlien titrating the di- 

 chromate solution." 



This occupies half a page, sugar is elaborately 

 treated in four pages, tanning in two and a half, 

 dyeing in as many as seven, mineral oils, vegetable 

 oils, and fats in seven, and so on. The most useful 

 page in the volume is the bibliography of important 

 works of reference at the beginning, though it is 

 scarcely worth the price of the book. J. B. C. 



t 



