408 Notices respecting New Books. 



and in the former's three-volumed treatise on the Algebra of Logic 

 (1890, 1891, 1895) the whole Boolian method is perfected. It is 

 this method which is expounded by Couturat concisely and clearly 

 in a book of 92 pages. Although the calculus was devised to 

 express the principles of reasoning, it may be developed from the 

 formal point of view as an algebra based upon certain assumed 

 axioms. This may be done without any attempt to interpret the 

 results as corresponding to actual operations of mind, or to apply 

 them to logical problems. Such, broadly speaking, is the aim of 

 Couturat in his dainty treatise. He treats the calculus as a form 

 of algebra and not as logic. The translation lias been admirably 

 done; it is difficult to imagine that the original French could be 

 more lucid and more exact than in its English dress. It is sad to 

 realize that nothing more will come from the hand of this gifted 

 Trench author, who lost his life by an accident in the early months 

 of the war. 



Practical Physical Chemistry. Alex Ejndlay, M.A., Ph.D., D.Sc. 

 Third Edition enlarged. Longmans, Green & Co., 1914. Price 



4s. 6d. net. 



Ln" this third edition of a very useful manual several fresh 

 subjects and new experimental methods have been added, such as 

 the determination of vapour densities by the methods of Blackmail 

 and of Menzies, and the application of vapour-density determi- 

 nations to the analysis of binary mixtures of normal liquids; 

 application of vapour-pressure measurements to the determination 

 of molar weight ; determination of minute solubilities and of 

 hydrolysis by conductivity measurements, &c. References to 

 original literature have been added to most of the chapters, and 

 an appendix has been inserted giving tables of some of the more 

 important physical data relative to the subject. 



Elements of Optics for the use of Schools and Colleges. Geoege "W. 

 Paekee, M.A. Pp. 122. London, New York, & Bombay: 

 Messrs. Longmans, Green & Co. Price 2s. 6d. 



Theee is not very much to be said about this little book. It 

 describes in a very simple manner, involving only algebra and 

 elementary trigonometry, the fundamental phenomena of geo- 

 metric optics. The author claims to have endeavoured to make 

 the book as attractive as possible; it contains little, however, 

 besides the outlines of mathematical proofs. No attempt has 

 been made to add to the attractiveness and educational usefulness 

 of the book by describing experiments which the pupil might make 

 for himself. No subject lends itself more readily to simple expe- 

 rimental treatment than the subject of light. A lens, a prism, 

 a plane and a concave mirror, and a few pins are all the apparatus 



