Page:Popular Science Monthly Volume 77.djvu/456

450 effect, 1896; radium, 1898; atomic disintegration, the transformation of matter, the thermal effect of radioactivity, and intra-atomic energy, 1903. I am unable to locate the sixth decimal idea in recent catalogues.

J. J. Thomson likens the discovery of Rontgen rays to the discovery of gold in a sparsely populated country. Workers come in large numbers to seek the gold, many of them finding that "the country has other products, other charms, perhaps even more valuable than the gold itself."

The chief value of Röntgen's discovery was not that it furnished us a "new kind of light for the investigation of dark places," but in the fact that it led a host of workers to study vacuum-tube discharges—the discharge of electricity in gases and the effects of such discharges on matter itself. The old dusty Crookes tube was taken down from the far corner of the upper shelf and regarded with new interest. In a day it had ceased to be a forgotten, though curious, plaything, and had become a powerful instrument of research. It was before Röntgen's discovery that a well-known professor said to me that he considered it foolish for one to spend any part of his departmental appropriation for a vacuum; that when he paid out money he wanted something in return—not an empty space. And yet this man was familiar with the work of Faraday and of Crookes, both of whom with prophetic mind had foreseen and foretold. Let me quote from a lecture by Faraday, N on the significant subject, "Radiant Matter."

I may now notice a peculiar progression in physical properties (of matter) accompanying changes of form, and which is perhaps sufficient to induce, in the inventive and sanguine philosopher, a considerable degree of belief in the association of the radiant form with the others in the set of changes I have mentioned.

As we ascend from the solid to the fluid and gaseous states physical properties diminish in number and variety, each state losing some of those which belong to the preceding state. . . . The varieties of density, hardness, opacity, color, elasticity and form, which render the number of solids and fluids almost infinite, are now supplied by a few slight variations in weight and some unimportant shades of color.

To those, therefore, who admit the radiant form of matter, no difficulty exists in the simplicity of the properties it possesses. . . . They point out the greater exertions which nature makes at each step of the change and think that, consistently, it ought to be greatest in the passage from the gaseous to the radiant form.

The lecture from which the foregoing is a quotation was delivered in 1816, when Faraday was but twenty-four years old. Let me quote again, this time from a lecture by Sir William Crookes, delivered sixty years later, more than twenty years ago, on the same subject—" Radiant Matter."