The atomic weights of nearly forty of the ninety or more chemical elements out of which everything in the universe is built have been definitely determined by University chemists in the course of investigations begun 35 years ago and extending up to the present time.

Largely on account of his work in this field of chemical research Professor Theodore W. Richards '86, Nobel prize winner in 1914 and Director of the Wolcott Gibbs Memorial Laboratory at the University, has been appointed a member of the international committee on elements, while Professor Gregory P. Baxter '96, formerly a pupil of Professor Richards and now an independent investigator at the University, has been chosen for the International committee on atomic weights.

The data obtained in the University laboratories by these two men and their assistants are now being used by thousands of chemists throughout the world in their daily work, and the researches in which they were obtained have thrown new light on the perplexing problem of the nature of matter.

The a weights of the elements are described as the relative weights in which these elements combine with each other to form the countless substances of which the universe is constructed. These weights have usually been found to be amazingly constant. Silver from all parts of the world and from many different ores has always the same atomic weight Copper from Europe is identical in this respect with that mined under the bottom of Lake Superior.

Most astonishing of all, Professor Baxter's work at the University long since proved that the iron and nickel which fall from the sky in meteorites coming from the spaces for beyond the earth's orbit have exactly the same atomic weights as iron and nickel from the earth a fact cited as indicating in one respect, at least, the unity of the universe.

The most important single result of the study of atomic weights conducted at the university is said to be the discovery, first proved definitely some years ago by Professors Richards and still holding good through recent careful tests, that there exists at least two kinds of lead instead of one. It was found that lead from radium minerals, while it possesses properties exactly similar to those of ordinary lead, has a distinctly smaller atomic weight, 2061 as against 207.2.

The lead from radium minerals is supposed to come from the decomposition of radium. Why its atomic weight is different from that of ordinary lead, whether ordinary lead may not itself prove to be a mixture of lighter lead with a heavier variety, perhaps due to the disintegration of the element thorium, and whether other elements, hitherto supposed to be final and invisible, may not also prove to be mixtures and thus open up a whole series of new problems as to the composition of mater, are questions to which the answers are being eagerly sought all over the world today.

Professor W. D. Harkins of Chicago has strong evidence that ordinary chlorine is a mixture, and F. W., Aston of Cambridge, England, by an entirely different method, indicates that many other elements are probably likewise composed of atoms of different weights.

Harvard chemists are working at