12 PRESIDENTIAL ADDRESS. — SECTION I. 



of the relative weight to be assigned to each atom. It was early 

 observed that the values of the atomic weights appeared to be 

 whole numbers, and, taking hydrogen as unity, the other atomic 

 w^eights seemed to be whole multiples of that of hydrogen. This 

 circumstance led to the enunciation of the doctrine that all the 

 elementary atoms were formed from one primary substance, and as 

 hydrogen was the lightest material known, it seemed not un- 

 reasonable to assume that the elements might be regarded as 

 modifications of hydrogen. This was the basis of the famous 

 hypothesis of Prout. It had at first the effect of weakening the 

 atomic theory, but careful determinations showed that the atomic 

 weights were not whole numbers, and the hypothesis was eventually 

 discarded. Had Prout had at his disposal the facts we now have, 

 it would have been much more difficult to overthrow his 

 hypothesis. From Prout' s time until nearly the end of the last 

 century the atom reigned supreme. Now and again a daring 

 innovate questioned the inviolability of the atom, but he did not 

 meet with much support and his " conclusive " experiments were 

 explained away. I have not considered any hypothesis which 

 goes further than the atom — the ultima ratio of all things, a sacred 

 unit to be revered and worshipped. 



The questions must always have recurred to thoughtful men : 

 " Why should the atoms be different ? " — " Why may they not 

 have been formed from one primordial substance ? " To these 

 questions I propose to furnish answers in the course of my address. 



Now, let us examine some of the theories which have been 

 advanced to account for the existence of tangible matter. About 

 the middle of the last centurj/ the remarkable character of vortex 

 motion seems to have impressed itself upon the attention of the 

 mathematical physicists. Von Helmholtz in 1858 enunciated his 

 theory of vortex motion, in which he showed that we might con- 

 ceive that the rotating parts of a continuous incompressible fluid 

 preserve their identity when once they have been set in motion. 

 So that, if a portion of the ether acquires this motion by any means, 

 that ])ortion is for ever marked off from surrounding portions. 



Vortex rings can be formed in the air by any smoker, and can 

 probably be set up in the ether by electrical discharges. Lord 

 Kelvin developed the theory and postulated that matter as we 

 know it may be made up of these rotating vortex rings, interlocked 

 in such a fashion that they cannot escape from each other's clutches. 

 Clerk Maxwell, J. J. Thomson and many others also worked at 

 this theory, and, as far as mathematical expression goes, the theory 

 is fairly complete. Perhaps some day the necessary experimental 

 evidence may be forthcoming, which will establish the truth — or, 

 on the other hand, show the fallacy — of the reasoning. 



These vortex atoms must be perfectly elastic. The vortex theory 

 seeks to explain, not merely the constitution of matter, but also 

 the nature of heat, light and electricity. Another theory which 

 met with some support is that of Boscovich, which postulates that 

 the ultimate atom is merely a centre of force, possessing a definite 

 mass, and, consequently, inertia. Time does not permit the 

 enumeration of other theories, very many of which may be studied, 



