Page:Harper's New Monthly Magazine - v109.djvu/421

Rh

they are stopped by any obstacle. They thus keep the vessel in which they are enclosed at a temperature a degree or two above surrounding bodies, at least in the case of the most active known substances, radium and its emanation. For radium converts its own intra-atomic energy into heat at so surprising a rate that it could, if all of the heat were economized and none allowed to escape, raise its own weight of water from ordinary temperature to the boiling-point every hour.

The number of atoms breaking up in any perceptible portion of radium salt must be reckoned in millions per second; nevertheless the proportion of atoms which are thus undergoing transformation at any one time is extremely small. If they could be seen individually most of them would appear quiescent and stable. Of every ten thousand atoms, if a single one breaks up and flings away a portion of itself once a year, that would be enough to account for all the activity observed, even in the case of so exceptionally active a substance as radium; hence the apparent stability of ordinary matter is not surprising.

The thus-projected atomic fragments were measured by Rutherford, who found them deflected by a magnet in the opposite direction to the electron projectiles, and were therefore proved to be positively charged; but they are deflected so slightly that they must be very massive bodies, 1600 times as massive as an electron, or twice the atomic weight of hydrogen. A substance with this atomic weight is known, viz. Helium; and surely enough the discoverer of Helium, Sir W. Ramsay, working with Mr. Soddy, a recent colleague of Rutherford, has witnessed the Helium spectrum gradually develop in a tube into which nothing but radium-emanation had been put.

Matter then appears to be composed of positive and negative electricity and nothing else. All its newly discovered, as well as all its long-known, properties can thus be explained:—even the long-standing puzzle of "cohesion" shows signs of giving way. The only outstanding still-intractable physical property is "gravitation," and no satisfactory theory of the nature of gravitation has been so far forthcoming. I doubt however if it is far away. It would seem to be a slight but quite uniform secondary or residual effect due to the immersion of a negative electron in a positive atmosphere. It is a mutual force between one atomic sys-