TRANSACTIONS OF THE SECTIONS, 
Section A.—MATHEMATICAL AND PHYSICAL SCIENCE. 
PRESIDENT OF THE SEcTION.—Prorrssor H. lL. Canuenpar, LL.D., 
F.R.S. 
THURSDAY, SEPTEMBER 5. 
The President delivered the following Address :— 
My first duty on taking the chair is to say a few words in commemoration of the 
distinguished members whom we have lost since the last meeting. 
George Chrystal, Professor of Mathematics in the University of Edinburgh 
for more than thirty years, cfficiated as President of this Section in the year 
1885, and took a prominent part in the advancement of science as Secretary of the 
Royal Society of Edinburgh since 1901. Of his brilliant mathematical work and 
his ability in developing the school at Edinburgh I am not competent to speak, 
but I well remember as a student his admirable article on ‘Electricity and 
Magnetism’ contributed to the ‘Encyclopedia Britannica,’ which formed at 
that time the groundwork of our studies at Cambridge under Sir J. J. Thomson. 
It would be difficult to find a more complete and concise statement of the 
mathematical theory at the time when that article was written. One can well 
understand the value of such a teacher, and sympathise with his University in 
the loss they have sustained. 
John Brown, F.R.S., who acted as Local Secretary for the Association at 
Belfast in 1902, will be remembered for his work on the Volta contact effect 
between metals, which he showed to be in the main dependent on chemical 
action, and to be profoundly affected by the nature of the gas or other medium 
in which the plates were immersed. Although the theory of this difficult subject 
may not yet be completely elucidated, there can be little doubt that his work 
takes the first rank on the experimental side. 
William Sutherland, D.Sc., who at one time acted as Professor of Physics at 
Melbourne, is best known for his familiar papers on the subject of molecular 
physics in the ‘ Philosophical Magazine.’ His work was always remarkable for 
its wide range and boldness of imagination. Many of his hypotheses cannot yet 
be weighed in the balance of experiment, but some have already been sub- 
stantiated. For instance, his theory of the variation of viscosity of gases with 
temperature has been generally accepted, and results are now commonly 
expressed in terms of Sutherland’s constant. 
Osborne Reynolds, the first. Professor of Engineering at Owens College, was 
President of Section G in 1887, but belongs almost as much to mathematics and 
physics, in which his achievements are equally memorable. It would be hardly 
possible for me to enumerate his important contributions to the science of 
engineering, which will be more fittingly commemorated elsewhere. His mastery 
of mathematical and physical methods, while contributing greatly to his success 
as a pioneer in the engineering laboratory, enabled him to attack the most difficult 
problems in physics, such as the theory of the radiometer and the thermal 
transpiration of gases. His determination of the mechanical equivalent of heat 
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