

688 SCIENCE PROGRESS 



notable advance of the theory of the Sun's motion in space, which, like that first 

 established by Sir William Herschel in 1783, may lead after correction to a still 

 further development in our knowledge of the mechanism of the Universe. 



A. L. C. 



PHYSICS 



Laws of Physical Science. By Edwin F. Northrup, Ph.D. [Pp. vii + 210.] 

 (Philadelphia and London : J. B. Lippincott, 1917. Price 8s. 6d. net.) 



In the preface to this book it is pointed out that, while the data and mathematics 

 used in physical science have been classified and are readily accessible in many 

 reference-books, there is no handbook which summarises the general propositions 

 and important facts of the science. This gap the book is intended to fill, though 

 since it seems to have been written primarily for the guidance and " inspiration " 

 of students in other branches of Natural Science, the subject-matter is almost 

 entirely of an elementary character. It contains little that would not be discussed 

 in any standard college text-book. The laws are dealt with under the usual sub- 

 headings including mechanics, and each is followed by one or more references, 

 generally to familiar text-books, the author rightly considering that the treatment 

 given there is more likely to appeal to those not fully conversant with the subject 

 than that in the original papers. He has, however, made a conspicuous number 

 of exceptions to this excellent plan in favour of his own papers — even in one case 

 referring to results he has not yet published elsewhere ! 



The arrangement of the subject-matter in the section devoted to Heat and 

 Physical Chemistry is extraordinary, not to say careless ; for example, Carnot's 

 theorem is given before either law of thermodynamics and is separated from them 

 by facts concerning the platinum resistance thermometer, the expansion of liquids 

 and Dulong and Petit's law. Van der Waal's equation is given twice on consecu- 

 tive pages, and the equation attributed to Clapeyron is not that usually so known. 

 The other sections of the book are less open to criticism, and there is a satisfactory 

 index. There are, however, a good many typographical errors, and the letter 1 

 and the numeric 1 are confused in several places {e.g. pp. 13, ^7, 41 and 42). 

 These adverse comments, however, refer in the most part to minor points, and the 

 book may possibly be found a useful compendium by students in other fields whose 

 work brings them only into occasional contact with this branch of science. It 

 would also serve as a useful summary of facts for a prospective intermediate or 



pass examinee. 



D. O. W. 



CHEMISTRY 



The Theory and Use of Indicators. An account of the chemical equilibria of 

 acids, alkalies, and indicators in aqueous solution, with applications. By 

 E. B. R. Prideaux, M.A., D.Sc. [Pp. vii + 375, with diagrams and 

 tables.] (London: Constable & Co., Ltd., 1917. Price 125-. 6d. net.) 



In view of the fundamental mportance of indicators from the standpoint ot 

 theoretical and, more especially, practical chemistry, it is somewhat surprising that 

 English chemists should have had to wait so long for the appearance of a reliable 

 book on the subject : doubtless this has been due to our dependence on German 

 chemical literature, which latter formed in its way a "key-industry" as regards 

 chemical activities, and for that reason, if for no other, one would welcome the 

 appearance of Dr. Prideaux's work, as being a further step in freeing us from our 

 bondage. 



