April 9, 1908J 



NATURE 



531 



The laws governing floating bodies are touched 

 upon, and investigation is carried so far as to cover 

 the eminently practical and up-to-date case of the 

 floating dock. From these considerations, the author 

 proceeds to deal with the subject of fluids in motion, 

 which constitutes the essential feature of the book. 

 He makes Bcrnouilli's theorem his starting-point, 

 following on to Torricelli's law and the theory of flow 

 through mouthpieces with the coefficients due to 

 various forms of orifice. Then, having dealt with 

 weirs, he directs his attention to fluid flow through 

 pipes and channels, explaining the well-known basic 

 formula, 



and quoting the values assigned to the coefficient by 

 Chezy, Bazin, Darcy. Ganguillet and Kutter, and 

 others. This brings us to chapter vii., in which we 

 find a description of the methods adopted for gauging 

 the flow of water through an orifice, in streams and 

 in pipes, including a brief reference to Stromeyer's 

 suggestion for the use of a chemical agent. Chapter 

 viii. treats of the impact of water on vanes, and 

 thence it is a natural transition to water-wheels and 

 turbines in chapter ix. Both this chapter and the 

 following, on pumps, are very full and explicit, and 

 are effectively illustrated by a number of typical ex- 

 amples. Chapter xi. is devoted to an exemplification 

 of the application of hydraulic power to industrial 

 purposes by means of various machines. In two short 

 concluding chapters the author deals with the modern 

 investigation of stream-line flow and the resistance 

 to motion of bodies in water. 



An admirable feature of the work is the large 

 number of worked numerical examples. The type 

 is clear and the illustrations are good. Altogether the 

 work forms an excellent text-book, and is cordially 

 to be recommended to students of this most interesting 

 and useful science. 



TECHNICAL CHEMICAL ANALYSIS. 

 Traite complet d'Analyse chimiqtie apptiqiiee aiix 

 Essais industriels. By J. Post and B. Neumann. 

 Second French edition, by Dr. L. Gautier. Vol. i., 

 part i. (pp. 217, price 6.50 francs), ^'ol. ii., part i. 

 (pp. 202, price 6 francs). (Paris : Librairie scien- 

 tifique, A Hermann, 1907-8.) 



THE present review is concerned with the first two 

 instalments of the second French edition of a 

 German treatise on technical chemical analysis, which 

 has already passed through three editions in the 

 original. The complete work will consist of two 

 volumes divided into eight sections, each section deal- 

 ing with some special branch of analytical practice, 

 and the editors have secured the cooperation of some 

 twenty-seven eminent contributors in order that the 

 various chapters may embody the results of the latest 

 experience. Judging by the style of the first two sec- 

 tions, now before us, it would appear that the editors 

 are aiming rather at a clear and succinct outline of 

 contemporary analytical method, and of the genera! 

 NO. 2006, VOL. 77] 



nature of the materials to which they are applied, than 

 at an elaborate and detailed treatise. Subject to this 

 proviso, they may be congratulated on having so 

 far achieved a considerable measure of success, and 

 their efforts may be commended to British chemists 

 who feel the need of a manual of this description. 



Vol. i., part i., deals with such subjects as 

 water, solid fuels, pyrometry, and gas analysis in a 

 fairly complete and satisfactory manner. The open- 

 ing chapter on water analysis (pp. 1-38), by Dr. H. 

 Vogel, of Berlin, is somewhat too compressed and 

 desultory to be of real use, and might be advan- 

 tageously enlarged in future editions. Then follows 

 an excellent resume by Dr. H. Langbein of the 

 methods in vogue for the chemical analysis and 

 calorific valuation of solid fuels (pp. 39-73) ; the value 

 of this chapter would have been enhanced by a fuller 

 treatment of the ash analysis of coals and its import- 

 ance in relation to the various uses of the raw fuel. 

 The third chapter, by Prof. B. Neumann, of Darm- 

 stadt, on pyrometry (pp. 74-126), deals very completely 

 with the various thermoelectrical and optical methods 

 used in technical practice, and so far as these methods 

 are concerned the treatment of the subject is all that 

 could be desired. The scanty references to the air 

 thermometer and to electrical resistance methods are, 

 however, to be regretted. 



The concluding chapter, on gas analysis (pp. 127- 

 217), also by Prof. Neumann, is disappointing in that 

 it deals with little else than the crudei and un- 

 trustworthy methods of Hempel and Orsat (or various 

 modifications of them), which have long been the 

 despair of workers, who instinctively demand some- 

 thing both accurate and convenient, and which, we 

 had hoped, were being rapidly discarded in technical 

 laboratories. In these days, when the applications of 

 gaseous fuels are increasing daily, the introduction 

 of really accurate methods of gas analysis in technical 

 practice is fast becoming an urgent necessity, and it 

 is quite a mistaken notion that methods of precision 

 are necessarily inconvenient or tedious, and therefore 

 unsuited to the exigencies of a works laboratory. The 

 opinion of Dreschmidt, quoted on p. 136, as to the 

 incompleteness of the absorption of carbonic oxide by 

 an ammoniacal solution of cuprous chloride may be 

 disputed, since it can easily be demonstrated that a 

 properly prepared and fresh solution will absorb the 

 gas almost as rapidly, and, for all practical purposes, 

 as completely, as a caustic alkali absorbs carbon 

 dioxide. It may also be remarked that there is no 

 reference to gas calorimetry in this chapter. 



Vol. ii., part i., dealing with the physical, 

 mechanical, and chemical testing of limestones, mor- 

 tars, cements, ceramic products, glass, and the like, 

 has been entrusted to Drs. H. Seger and E. Cramer, 

 of Berlin. Their treatment of the subject is admirably 

 clear and succinct, and will certainly be appreciated 

 by all genera! readers. Whilst there is nothing very 

 new, good judgment has been exercised in selecting 

 the best methods and appliances, and the whole is a 

 singularly w-ell-balanced production, and eminently 

 readable. The one fault to be found with their work 

 is the paucity of the references to analytical literature. 



