Chemistry and Physics. 157 



5. Quantitative Chemical Analysis; by Clowes and Cole- 

 man. 8vo, pp. 565. Philadelphia, 1911 (P. Blakiston's Son & Co.). 

 This text-book is so well known and widely used, both in Great 

 Britain, the place of its origin, and in the United States, that the 

 appearance of the present ninth edition requires no comment 

 except the statement that the text of the much improved eighth 

 edition, which appeared two years ago, has been carefully revised 

 with the result that some additions and improvements have been 

 made, and errors have been corrected. h. l. w. 



6. Photometric Paddle - Wheels. — James R. Milne has 

 recently described a new form of rotating photometric sector 

 similar to a paddle-wheel in appearance, and consisting, in one 

 form, of two flat, triangular vanes fixed to the shaft of a motor 

 by which they are rotated. The amount of light interrupted 

 depends on the azimuth of the base, which angular measurement 

 can be made with a high degree of accuracy. The author gives 

 a mathematical discussion of this new type of apparatus, in which 

 are deduced formulae for the intensities of the light transmitted 

 under different conditions, and for the greatest width of the 

 beam of ligrht that can be employed ; and a graphical tabulation 

 of the values of these formulas in different cases is provided. 

 The mounting and details of an actual instrument are also 

 described, together with an additional mechanism for the pur- 

 pose of automatically recording the photometric measurements 

 obtained. — Proc. Roy. Soc. Edinburgh, vol. xxxi, pp. 655-683. 



7. A Text-Book of Physics ; by Louis Bevier Spinney. 

 Pp. xi, 605. New York, 1911 (The Macmillan Co.).— This vol- 

 ume is designed primarily for use as a text in courses offered to 

 engineering and technical students. Hence, special emphasis is 

 laid on the practical aspects of the subject. Illustrations of phys- 

 ical laws are drawn as far as possible from familiar phenomena, 

 and physical principles are exemplified by numerous important 

 applications. Particular emphasis is placed upon the subject of 

 Mechanics. Also, it is expected that the book will be used as a 

 basis for class-room work and that it will be supplemented by a 

 course of experimentally illustrated lectures and suitable labora- 

 tory exercises. The text is up to date and includes, of course, 

 a discussion of ionization and radio-activity. A knowledge of 

 plane trigonometry and elementary chemistry is assumed. The 

 figures are large, well-drawn and interesting, and Gothic type 

 is used for emphasis. 325 problems for solution are distributed 

 throughout the volume. 



As regards minor details the book possesses both satisfactory 

 and unsatisfactory characteristics. For instance, on page 26 an 

 acceleration is given as " 2 miles per hour per minute," which is 

 very helpful to students who find difficulty in grasping the full 

 meaning of 2 miles per sec. per sec. On the other hand, the term 

 moment of inertia is introduced symbolically on page 39, but its 

 physical significance is first brought out on page 81. h. s. tj. 



