498 Notices respecting New Books. 



Plane Trigonometry for Colleges and Secondary Schools. 

 By Daniel A. Mure ay, Ph.D. (Longmans, 1899 : pp. xiii + 206.) 



The following extracts from the preface will serve instead of 

 an analysis. " Careful consideration has been given both to 

 the early difficulties and to the possible future needs of the 

 beginner. An endeavour has been made to introduce the several 

 topics in such a way that the pupil may have, from the very start, 

 an intelligent idea of each step in advance, as well as of the 

 ultimate purpose of the study." These statements have been 

 verified and are true. The Author is evidently an excellent 

 teacher of his subject. The text, figures, and typical examples 

 (worked out) are all good. It is an elementary work which gives 

 a clear account of Logarithms and provides a correct introduction 

 to more advanced text-books. There is an Appendix which gives 

 an " historical sketch " (such notes are also dispersed throughout 

 the text), " projection definitions of the ratios/' a note " on analy- 

 tical Trigonometry,'*' and one or two other advanced notes. There 

 is a further collection of exercises for practice at the end of the 

 book, with answers. 



Optical Activity and Chemical Composition. By Dr. H. Laxdolt. 

 Translated by J. McCrae. Ph.D. Pp.xi + 158. London : Whit- 

 taker & Co., 1899. 



This work is a translation of the eighth chapter of the first 

 volume of Graham-Otto's Lehrbuch der Chemie. Considering the 

 importance of optical tests in the examination of many organic 

 compounds, it may be safely asserted that a book devoted to this 

 subject fills a decided gap in chemical literature. Within the 

 compass of some 150 small pages, Dr. Landolt gives a very com- 

 plete account of the present state of our knowledge on this subject. 

 The book is divided into three parts. Part I. deals with the general 

 principles of optical activity. Part II. is concerned with the 

 connexion between the rotatory power and the chemical composition 

 of carbon compounds, and contains a Aery clear and interesting 

 historical account of this matter. Part III. is devoted to the con- 

 nexion between the degree of rotation and chemical constitution. 

 In this concluding portion of the book the imperfect and frag- 

 mentary nature of our present knowledge regarding this subject 

 is fully exhibited ; a vast amount of experimental work still remains 

 to be done before any satisfactory general explanations ran be 

 arrived at. — The translation has been admirably executed by Dr. 

 McCrae. 



