March 6, 19 13] 



NATURE 



already made on the provision of instruments for 

 measuring- and recording- temperatures above the 

 range of the mercurial thermometer. Without the 

 electrical pyrometer comparatively little would 

 have been accomplished. 



Another subject of the greatest chemical and 

 commercial importance is the utilisation of atmo- 

 spheric nitrogen, which has been treated in a com- 

 plete and interesting- article by Prof. Crossley. 

 Up to the present the fixation of nitrogen in the 

 form of nitrate has perhaps attracted most atten- 

 tion, and has been practised on the largest scale, 

 but the recent announcement that the Badische 

 Anilin- u. Soda-Fabrik has actually started the 

 manufacture of ammonia from the combination 

 of gaseous nitrogen and hydrogen by Haber's 

 process is a further step of great significance. 



Among other new subjects unrepresented in the 

 former edition are "Colloids," by Dr. J. C. Philip, 

 and "Corrosion and Fouling of Steel and Iron 

 Ships," by Prof. Vivian B. Lewes; while several 

 others, such as "Explosives," by Mr. G. H. Perry, 

 and "Matches," by Mr. E. G. Clayton, have been 

 largely added to and brought up to date. There 

 is also a judicious unsigned historical article on 

 the liquefaction of gases. 



There are few deficiencies apparent on first 

 acquaintance with the dictionary, and in the pre- 

 sence of so much that is admirable, hyper- 

 criticism may be deprecated. The inequality in 

 length of the various articles is probably one of 

 the most difficult questions which come before the 

 editor in relation to such a work as this. The 

 most glaring case noticeable in the two volumes 

 before us is the assignment of 100 pages to 

 naphthalene, while fuel receives only twenty-four 

 pages and flame eight pages. In neither of these 

 articles is there any reference to the important 

 question of smoke production and prevention, 

 which is surely a question of chemical as well as 

 practical interest. 



The attention of the editor may also be directed 

 to the fact, though too late for remedy, that the 

 article on essential oils, though containing much 

 useful information, is distinguished from every 

 other important article in the book by the absence 

 of references or bibliography. It would probably 

 provide a slight shock for Prof. Wallach to find 

 ithat an article on this subject could be written 

 without mention of his name. The writer of the 

 article similarly ignores Schimmel's half-yearly 

 reports, which furnish a large body of valuable 

 information extending over many years, and 

 cannot yet be considered to be replaced in this 

 country by The Perfumery and Essential Oil 

 Record. 



All British chemists will certainly make fre- 

 NO. 2262, VOL. 91] 



quent use of the new edition of the dictionary, 

 and in doing so the majority will be glad of the 

 adoption of a system of abbreviations of the 

 titles of journals and books which is practically 

 identical with the system with which all are 

 familiar in the publications of the Chemical 

 Society, and is much to be preferred to the con- 

 tractions, often rather tiresome, used in the 

 previous edition. WAT 



PRACTICAL MATHEMATICS. 



(1) Practical Geometry and Graphics. By E. L. 

 Bates and F. Charlesworth. Pp. ix + 621. 

 (London: B. T. Batsford, 1912.) Price 4 s. net 



(2) Practical Mathematics. By E. L. Bates and 

 F. Charlesworth. Pp. ix + 513. (London : B. T. 

 Batsford, 1912.) Price 35. net. 



(3) Analytical Geometry. A First Course. By 

 C. O. Tuckey and W. A. Nayler. Pp. xiv + 367. 

 (Cambridge : University Press, 1912.) Price 55. 

 net. 



(4) A Preparatory Arithmetic. By C. Pendlebury. 

 Pp. xiv + 185 + xxx. (London : George Bell and 

 Sons, Ltd., 1912.) Price is. 6d. 



(5) Les Anaglyphes Geometriques. By H. Vuibert. 

 Pp. 32. (Paris : Librairie Vuibert, n.d.) 



i 1 ) I ^HE contents of this volume fall into three 

 1 sections: (a) plane geometry; (b) 

 graphics; (c) descriptive geometry. The first 

 deals with the calculation of areas and volumes, 

 the fundamental geometrical constructions and the 

 chief properties of the circle and conic. In the 

 second the student is shown how to apply graphical 

 methods to the solution of practical problems in 

 mechanics, considerable space is devoted to the 

 consideration of harmonic motion and systems of 

 frameworks, and allusion is made to the use of 

 vector products. The last section, which occupies 

 i nearly 200 pages, contains as full an account of 

 the methods of practical solid geometry as any 

 ordinary technical student is likely to require. The 

 diagrams are clear and the quality of the examples 

 is distinctly good. 



(2) The authors have attempted to collect in as 

 concise a form as possible all those portions of 

 mathematics which are likely to be of use to prac- 

 tical students. The volume is self-contained in 

 the sense that no previous knowledge is assumed, 

 and its contents are designed to supply material 

 for a course lasting between two and three years. 

 About two-thirds of the book is devoted to arith- 

 metic, algebra and geometry; due prominence is 

 given to graphical methods; the treatment of 

 mensuration is excellent, and the selection of those 

 geometrical properties and ideas with which it is 

 considered students should be familiar has been 

 made with great care. The concluding part of the 



