570 Notices respecting New Books. 
an important set of functions ; and he will find opportunity of 
testing his powers by consideration of the examples which are 
appended to most of the Chapters in Part I. The physicist, agaiu, 
who is face to face with a practical problem will find, if not 
exactly what he needs, something very near to it in one or other 
of the many solutions presented in Part II. The author does not 
claim to give all the methods which have been used for measuring 
conductivity; but we think a reference might have been made to 
Yamagawa's experiments, in which a sphere of stone was subjected 
to a periodic surface variation by alternate immersions in boiling 
water and melting ice. The results are certainly of a higher 
order of accuracy than those of Ayrton and Perry with the 
cooling sphere. 
Seclis Vortrage ilber das Thermodynamische Potential. By J. J. 
tan Laab. Priedrich Vieweg und Sohn. Braunschweig, 1906. 
These lectures exemplify the use of the thermodynamic potential 
in the treatment of the outstanding problems of solution and 
saturation. They are prefaced by two polemical lectures in which 
the author criticises in a lively manner the worshippers of the 
osmotic pressure. 
The Scientific Papers of J. Willaed Gibbs. In Two Volumes. 
Longmans, Green & Co. 1906. 
These volumes contain in attractive form the important contri- 
butions made to scientific journals and transactions by the late 
Professor Willard Gibbs, of Yale University. Undoubtedly his 
greatest work was in connexion with thermodynamics. His first 
paper on Graphical Methods appeared in 1873 ; and in 1876 and 
1878 appeared in two memoirs the remarkable and truly original 
discussion of the equilibrium of heterogeneous substances. It is 
a great advantage to have these papers together and easily acces- 
sible. The thermodynamic papers fill the first and larger volume. 
In the second volume the contents are of varied character; but 
probably the most interesting sections are those which concern 
vector analysis and multiple algebras. Here the mathematician 
will find some food for thought. The first volume is prefaced 
with a biographical sketch by H. A. Bumstead, and a complete 
bibliography. The portrait which forms the frontispiece shows a 
clear cut intellectual face of the best Kew England type. 
A Compendium of Spherical Astronomy. By Simon Newcomb. 
The Macmillan Company, Xew York, and Macmillan & Co., 
London. 1906. 
The precise nature of the present volume is indicated by the 
continuation of the title, — " with its application to the determi- 
nation and reduction of positions of the fixed stars." It is, as 
we learn from the preface, the first of a series, intended not only 
