680 Scientific Intelligence. 



manufacturers of the instruments described are indicated. The 

 appendix comprises a fairly long table of melting-points of com- 

 pounds suitable for microscopic work, the periodic table, and a 

 list of reference books. The diagrams are large and clear, and 

 the entire volume seems admirably adapted to meet all the require- 

 ments for which it was intended. h. s. u. 



9. Hancocks Applied Mechanics for Engineers ; revised and 

 rewritten by N. C. Riggs. Pp. xiii, 441, with 289 figures. New 

 York, 1915 (The Macmillan Co.). — "In the revision of this text, 

 although rather extensive changes in method of treatment have 

 been made in certain parts, the general subject matter and order 

 of arrangement have been, in the main, retained." The most 

 important points of difference between the present edition and 

 its predecessor (see vol. xxviii, page IS) may be noted as follows. 

 The chapter formerly entitled " Dynamics of Machinery " is 

 now called "Dynamics of a Rigid Body" and, because of its 

 relatively greater difficulty, it has been transferred to a later 

 position in the book. More extensive use is now made of graph- 

 ical methods. The graphical and analytical methods are devel- 

 oped side by side and many problems are proposed for solution 

 by both processes. The emphasis on the graphical methods has 

 necessitated the introduction of much new material, especially in 

 the construction of stress diagrams for trusses, and in the numer- 

 ous applications of the equilibrium polygon. The problems 

 illustrating the principles follow immediately after the develop- 

 ment of the principles and are of such a nature as to require 

 original thinking and to preclude the possibility of mere substi- 

 tution of numerical data in the proper formulae. The number 

 of new problems added is about two hundred. On the whole, 

 the book has been appreciably improved by the process of 

 revision. h. s. tj. 



10. Electricity for the Farm ; by Frederick Irving Ander- 

 son. Pp. xxiii, 265, illustrated. New York, 1915 (The Mac- 

 millan Co.). — "This book is designed primarily to give the 

 farmer a practical working knowledge of electricity for use as 

 light, heat, and power on the farm." The subject matter is pre- 

 sented in three Parts which deal respectively with water-power, 

 with electricity, and with gasoline engines, windmills, storage 

 batteries, etc. The text is elementary, practical, thorough and 

 adequate. In other words, no previous acquaintance with scien- 

 tific matters is presupposed. Typical examples of the design and 

 installation of small electrical plants are given. The text includes 

 tables of numerical data and simple formulae for calculating all 

 necessary quantities, such as: the discharge of water from weirs, 

 spouting velocity, "head," horsepower, pipe friction, Ohm's law, 

 etc. The text-figures are numerous and well chosen, and the 

 half-tone illustrations are attractive. The author's style is pleas- 

 ing and the text reads like a novel in several places. The volume 

 should be very helpful to all who live in the country and who 

 desire to take advantage of the opportunities afforded by their 

 surroundings. - h. s. tj. 



