The general results of these attempts was to re-enforce the validity of sound scientific method _within its own sphere_. But, at the same time, it was felt likely to prove an unreliable guide elsewhere. THE NEW PHYSICS.--Meanwhile, while the logic of science was being scrutinised by philosophers, scientific research was itself going steadily forward, and fresh discoveries of a highly important nature were coming to light. In the sphere of physical science, more especially, revolutions of Copernican proportions quietly took place. The whole subject of physics is of a highly technical nature, quite unsuitable for discussion here, and, indeed, entirely beyond the range of the present writer. To indicate the nature of the discoveries which were made, however, involves few technicalities: though the method by which these were demonstrated and established must remain obscure to all but mathematical specialists. COLLAPSE OF THE ATOMIC THEORY.--Dalton's theory of atoms was described in a previous chapter. It is hardly possible to exaggerate the importance attached by materialists, ever since Lucretius, to the conception of indivisible and indestructible atoms. It was regarded as integral to materialism, and never was the prestige of this theory higher than during the nineteenth century, which "will go down in scientific history as the era of the atomic theory of matter." Towards the close of the century, the theory collapsed. Atoms were found to be neither indivisible nor indestructible; and the process of the breaking up of the atom has actually been observed. As is very generally known, it is in the case of a particular element, _radium_, that this phenomenon occurs. That substance, wherever it occurs, is undergoing a continual process of disintegration; radium atoms are continually breaking up into more elementary bodies. Were it not for the fact that radium itself is the product of the disintegration of another element, it would be impossible to account for its survival. It continually evaporates (the life of radium is only 2500 years) but it is as continually renewed by the infinitely slower disintegration of uranium. ELECTRONS.--The particles into which the radium atom disintegrates are known as _electrons_. And according to the new theory of matter, not only radium atoms, but the atoms of all the other elements (hitherto regarded as irreducible) are composed of electrons, differently grouped. The radium atom is infinitely more unstable than the atoms of the other elements; but it is possible to conceive of the disintegration of these also. They are all alike composed of the same elementary particles--different compounds of the same primitive substance.