We regret that we were compelled last week to omit
all mention of Sir Joseph Thomson's presidential address at the opening meeting of the British Association at Winnipeg. It was an admirable address, being both clear and stimulating. After condemning the practice of premature specialisation in education for the sake of gaining scholarships, Sir Joseph Thomson declared that nearly every study is useless by itself. "I have been pleading," he said, "in the interests of physics, for the greater study of mathematics by physicists. I would also plead for a greater study of physics by mathematicians." If one could trace the origin of the most important scientific ideas, it would be found in the attempt to explain some apparently trivial phenomenon. Just as water-vapour refuses to condense into rain unless there are particles of dust to- form nuclei, so an idea before taking shape requires a nucleus of solid fact round which it can condense. Reviewing his own subject of experimental physics, Sir Joseph remarked - that the discovery of the Röntgen rays was an incentive to physical research which was unparalleled. The discovery of these rays was like "the discovery of gold in a spt-rsely populated country." The theory of the structure of matter had been revolutionised. Much was known already of the nature of negative electricity. But was positive electricity also molecular in structure P Per his part, he thought the evidence was in favour of the view that it was.