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XI. Notices respecting New Boohs. 



An Introduction to Physical Measurements, with Appendices on 

 Absolute Electriml Measurement, §c. By Prof. E. Kohlrausch. 

 Third English edition, translated from the Seventh German edition, 

 by T. H.Waller, B.A., B.Sc, and H. E. Procter, F.I.O., F.C.S. 

 London : J. and A. Churchill, 1894. 



O OME time ago reference was made in these pages (Phil. Mag. 

 ^ [5] vol. xxxvii. pp. 334, 502) to the fact that the earlier 

 editions of this work had become somewhat out of date by reason 

 of the widening of the scope of physical measurements. Prof. 

 Kohlrausch very rightly pointed out that the fault did not lie on 

 his side, as the latest (seventh) German edition contained a very 

 large amount of new matter. This edition now becomes accessible 

 to us in the form of an English translation. 



Prof. Kohlrausch has aimed at giving a tolerably comprehensive 

 list of experiments which may be performed in a physical labo- 

 ratory, as exercises for students or as parts of a physical research. 

 This wideness of aim necessarily entails a certain amount of brevity 

 of description, and consequently details of apparatus are generally 

 omitted. The book differs in this respect from others of its class, 

 the majority of which are either intended to meet the wants of 

 special students or else have been compiled primarily for use in 

 some particular laboratory: in either case the details referring to 

 construction or arrangement of apparatus are often found inapplic- 

 able when the book comes to be used under other conditions. 

 Prof. Kohlrausch has omitted mere lecture-experiments and such 

 as are designed to establish the truth of physical laws : it is 

 assumed in all cases that the experiment is undertaken to deter- 

 mine some physical constant. The omission of the determination 

 of coefficients of absolute expansion of liquids by heat, and the 

 measurement of wave-lengths by the biprism, may be due to this 

 cause, although the former are often required in physical work. 

 A more important defect is the absence of all reference to the 

 measurement of latent heat, either of fusion or vaporization. In 

 connexion with electricity and magnetism the number of experi- 

 ments which might be described is now so great that a selection 

 becomes necessary, and in the present volume the choice has been 

 on the whole a good one. The only measurement which does not 

 receive attention is that of the mutual induction between a pair of 

 coils, no method being given for its determination. In describing 

 the various forms of galvanometer the D'Arsonval or suspended 

 coil type ought to have been included ; and in connexion with 

 Mance's method for the measurement of battery resistance the use 

 of a condenser with the galvanometer (Lodge, Phil. Mag. June 

 1877) should be referred to. It does not seem to be generally 



