1907. | Anmversary Address by Lord Raylegh. 83 
of his researches is given by him in the Abel Centenary volume (xxvi, 1902) 
of the ‘ Acta Mathematica. Two of his papers may be particularly referred 
to, both of 1895. One of these deals with the reduction of the Theory and 
General Multiply-periodic Functions to the Theory of Algebraic Functions, 
with a view to their expression by Theta functions; this was one of the 
life problems of Weierstrass, who did not, however, during his lifetime, 
publish anything more than several brief indications of a method of solution. 
Professor Wirtinger’s memoir obtains a_ solution, and is, moreover, 
characterised throughout by most stimulating depth and grasp of general 
principles. This paper was followed by two others, one continuing the 
matter in detail, the other making an application of its principles to the 
general Theory of Automorphic Functions. Another extensive paper, which 
obtained the Beneke Prize of the Royal Society of Gottingen, deals with the 
general Theory of Theta Functions. In it he obtained results of far-reaching 
importance, for Geometry as well as for the Theory of Functions, the full 
development of which will require many years of work. 
HucuHes MEDAD, 
The Hughes Medal is awarded to Principal Ernest Howard Griffiths. 
Principal Griffiths has conferred great benefit on physical science by his 
series of measurements of fundamental constants, mainly in the domain of 
thermal and electric energy. At a time when the equivalent of the thermal 
unit in mechanical energy stood urgently in need of revision, he devoted 
himself to the problem with all the refinements and patient manipulation 
that could be devised, the result being a value for Joule’s equivalent which 
at once acquired authority in the lght of the evidence produced, and 
largely confirmed the corrections already advanced by Rowland and others. 
A main cause of discrepancy had been found to be the variation of the 
thermal capacity of water with the temperature; and by an investigation 
in which this variation was determined, Griffiths elucidated and correlated 
fundamentally the work of previous observers, from Joule onward. Of 
special importance also, in the domain of chemical physics, was an investiga- 
tion of the depression of the freezing point of water by very dilute 
admixture of dissolved substances, wherein he verified, with all the 
refinement of absolute physical determinations, that the change of freezing 
point ran exactly parallel to the electric conductivity when the dilution of 
the electrolysable salt was comparable to that of gases, being twice as much 
per molecule as the standard value of the depression for non-electrolytes. 
