486 



SCIENCE 



[N. S. Vol. XXXVI. No. 928 



once one would infer there is no relationship 

 between the phenomena. However, Mr. King 

 analyzes the lines by subdividing them into 

 groups, and concludes " that a close corre- 

 spondence does not exist, but there is a gen- 

 eral agreement as to magnitude of the two 

 eilects when the means of a large number of 

 lines are considered." I should like to add, 

 that the " means of a large number of lines," 

 leaves much to be desired in the proof of a 

 relationship. Mr. King's method of subdi- 

 vision carries with it another suggestion. 

 Wben he divides the separations into small, 

 medium and large, he reduces the number of 

 types of separation in each class. For clearly 

 a line whose separation is small does not be- 

 long to the same type as one whose separation 

 is large. Again he selects the ratio of each of 

 three subdivisions to low, medium and high 

 displacement respectively. This gives arbi- 

 trarily nine divisions. By this method he 

 shows there is an approach toward uniform- 

 ity in relative magnitude. The suggestion is, 

 what may we expect when these groups are 

 broken up into real series types? Comparing 

 the three iron lines mentioned above gives 

 nothing of promise, although close measure- 

 ment may show two of them to agree. But 

 in the absence of an established series one can 

 not affirm that these lines belong together. 

 If this point has any merit, it would be worth 

 while to compare substances among whose 

 lines definite series have been established. 



The tabulated data for the author's two 

 substances lack just one thing, viz., the ultra- 

 violet spectrum, to make them the most com- 

 plete study which has appeared. 



B. E. Moore 



University op Nebraska, 

 August, 1912 



Introduction to General Thermodynamics. 



By Professor Henry A. Perkins, Trinity 



College, Hartford. Wiley and Sons. 



Recognizing the lack of suitable text-books 



in English on thermodynamics for students 



of physical chemistry, the author in writing 



this book has attempted to make good the 



deficiency. 



The volume comprises some 225 pages of 

 octavo size subdivided into eight chapters, the 

 titles of which in order are : General Heat 

 Relations; The First and Second Laws of 

 Thermodynamics; Entropy; Thermodynamic 

 Equations; Perfect Gases; Real Gases; 

 Change of State; The Solution of Problems. 

 At the end of the book there are eight tables 

 giving gas constants, thermoelectric and ca- 

 lorimetric constants of certain substances, 

 density and thermo-elastic coefiicients of cer- 

 tain liquids and solids, critical and Van der 

 Waals constants, coefficients of expansion of 

 gases and relation of pressure units in vari- 

 ous systems. 



The methods of presentation and demonstra- 

 tion employed by the author are for the most 

 part classical and it is therefore unnecessary 

 to refer to them specifically. The emphasis 

 laid upon the doctrine of available energy as 

 a means of interpretation of the second law is 

 notable. The various thermodynamic poten- 

 tials and the phase rule of Gibbs receive ap- 

 propriate attention. The last chapter is note- 

 worthy on account of the large number of 

 problems which are proposed for solution by 

 the student. Solutions of typical problems are 

 given. 



The scope of the book appears to be quite 

 adequate for the purposes which the author 

 has in view. A remarkable amount of mater- 

 ial is condensed into a small volume through 

 the aid of mathematical expressions; and al- 

 though the demands made upon the mathe- 

 matical knowledge of the reader are not very 

 great it would appear that the author prob- 

 ably intends the book to be used by students 

 having the advantage of a competent instruc- 

 tor. Professor Perkins has, in writing this 

 book, furnished a valuable addition to the 

 English text-book literature of thermodynam- 

 ics. 



A. P. Wills 



Astronomy in a Nutshell. By Garrett P. 



Serviss. Illustrated. G. P. Putnam's Sons. 



1912. Pp. xi + 261. 



There are so many excellent popular books 

 on astronomy and its different branches, that 



