INSIDE THE ATOM

Dominion, Volume 14, Issue 265, 3 August 1921, Page 5

INSIDE THE ATOM

TREMENDOUS DIFFICULTIES FACING INVESTIGATORS.

The general public has merely a vague idea that a clever Polish-French lady was lucky enough to drop -across radium in 1898. The fact is, of course, that Professor Curie and his wife were systematically following out the work of their'predecessors. For half a century physicists had been on the track of some deep secret of Nature of which they caught occasional glimpses. But the difficulties wore tremendous. Let us put it in this way (says "John o’London s Weekly"). Take the dot over the letter "i" as it is printed on this page. We know—we know before 1898—that several million atoms of matter could bo accommodated in a single line, shoulder to shoulder, so to speak, across the breadth of that tiny spot of ink! What the physicists and chemists wore trying to do was to get inside one of these extraordinary minute atoms, and see what it was made of. Sir Joseph J. Thomson, Cavendish professor of expenmen■tal physics at Cambridge, was the first to do so. The discovery did not depend so exclusively on radium as people imagine. Long before 1898 Sir W. Crookes had, though no one knew it, got the same phenomena by discharging electricity through little tubes of rare gas. Thomson was following this up, and the new* discovery of radium gave the clue. Those tiny atoms of matter were breaking up into particles which were far more minute. How could anylxidy oven make a mental picture of such inconceivably small things ? Sir J. J. Thomson did not merely get a mental picture of them. Ho made them register themselves on photographs. He weighed them, measured them, ascertained their speed, and gave the world a wonderful suggestion of how they lived within tho tiny dimensions of an atom. He directed thin streams of them on to a target which lit up as each particle struck it. He made them trace luminous paths through artificial fogs, so that they could bo photographed. Ho found and proved that the smallest of these particles—"corpuscles,” he called them, though they are now known as "electrons" —were so minute that, to put it > in his own recent words, "their linear dimensions are only about one-hundred thousandth part of those of atoms;" end it would take hundreds of millions of atoms in a continuous line to stretch

across the face of a penny. Very interesting, you may say, but docs it cut any ice? You mdy remember, on reflection, that this question was asked, rather disdainfully, when scientific men made the researches which led to the utilisation of gas, steam, or electricity. In this case there is an oven greater possibility. These electrons are shot out of' the atoms of matter at a speed which may reach, in good conditions, 160,000 miles a second. Here is locked up in the atoms all kinds of matter energy beyond all our dreams. The energy contained in a farthing is equal to 80,000,000 horse-power. There is fiore energy in the atoms of a square foot of coal than wo shall get in the ordinary way out of all the coal in Britain. Whether or no we shall succeed in tapping this energy remains to be seen. In any case, we have made a prodigious stride in the understanding of Nature, which is the first condition of our being able to develop its splendid resources. The atoms of all kinds of matter aro little worlds of these infinitesimal electrons magazines of extraordinary energy. Every arc. lamp is shooting them out at a prodigious speed. The sun is pouring them out in floods. They are "atoms of electricity; and it may be said in a sense that the whole material world is made up of electricity. It is something, at least, to have mastered the nature of that wonderful force. Sir J. J. Thomson a first suggestion of the .way in which these electrons are held together in the atom may give place to others, but the substance of his brilliant work remains.