TRANSACTIONS OF THE SECTIONS. 
SECTION A.—MATHEMATICAL AND PHYSICAL SCIENCE. 
PRESIDENT OF THE Secrion.—Professor J. H. Poynrrne, D.Sc., F.R.S. 
THURSDAY, SHPTEMBER 14. 
The President delivered the following Address :— 
Tue members of this Section will, I am sure, desire me to give expression to the 
gratification that we all feel in the realisation of the scheme first proposed from 
this chair by Dr. Lodge, the scheme for the establishment of a National Physical 
Laboratory. It would be useless here to attempt to point out the importance of 
the step taken in the definite foundation of the Laboratory, for we all recognise that 
it was absolutely necessary for the due progress of physical research in this country. 
It is matter for congratulation that the initial guidance of the work of the 
Laboratory has been placed in such able hands. 
While the investigation of Nature is ever increasing our knowledge, and while 
each new discovery is a positive addition never again to be lost, the range of the 
investigation and the nature of the knowledge gained form the theme of endless 
discussion. And in this discussion, so different are the views of different schools 
of thought, that it might appear hopeless to look for general agreement, or to 
attempt to mark progress. 
Nevertheless, [ believe that in some directions there has been real progress, and 
that physicists, at least, are tending towards a general agreement as to the 
nature of the laws in which they embody their discoveries, of the explanations 
which they seek to give, and of the hypotheses they make in their search for 
explanations. 
I propose to ask you to consider the terms of this agreement, and the form 
in which, as it appears to me, they should be drawn up. 
The range of the physicist’s study consists in the visible motions and other 
sensible changes of matter. The experiences with which he deals are the impres- 
sions on his senses, and his aim is to describe in the shortest possible way how his 
various senses have been, will be, or would be affected. 
His method consists in finding out all likenesses,in classing together all similar 
events, and so giving an account as concise as possible of the motions and changes 
observed. His success in the search for likenesses and his striving after concise- 
ness of description lead him to imagine such a constitution of things that like- 
nesses exist even where they elude his observation, and he is thus enabled to 
- simplify his classification on the assumption that the constitution thus imagined is 
areality. He is enabled to predict on the assumption that the likenesses of the 
future will be the likenesses of the past. 
His account of Nature, then, is, as it is often termed, a descriptive account. 
Were there no similarities in events, our account of them could not rise 
