'THE LIGHT OF THE FUTURE?**
Any strange tale of science which has come from Paris, and has filtered through an American medium of pub- lication, generally acquires a good
deal of artistic embellishment during its progress from one country to the other. The 'Cincinatti Enquirer' has been descanting upon the extraordin- ary properties possessed by a new substance recently received in a small leaden box by Professor Langley, of Washington, direct from Paris. The professor is a well-known physical scientist and lecturer at the Smithson- ian institution, so that any report ema- nating from him directly will be re- spected by the scientific world; but for the present—and until an authori- tative statement shall have been made by him— itwill be necessary for the public to exercise caution regarding the extent to which they give credence to the assertions now current in Ame- rica. These represent that the light of the twentieth century will be prac- tically without cost. Gas companies, unless in so far as they exist for supply- ing heat and power, may give up busi- ness; and the electric light, notwith- standing its promising debut in the arena of contesting illuminants, must suffer the fate of an early decline. Its sun, in fact, must be eclipsed ere yet the full glow of its morning ray has begun to be felt When people can purchase for a trifle a piece of green- ish stone no bigger than a five shilling piece, and hang it up from their gasaliers to furnish them with an in exhaustible supply of bright light it is not likely that they will pay gas bills or fees to electric lighting com- panies! Of course, there is no telling what may be done by the shareholders themselves, or a few of their sympa- thizers! Artemus Ward declared that when he put up a tent without a roof, and invited the people to pay a dol- lar to go in and see an eclipse of the moon, he did good business; but as a general rule, ordinary sane folks, when asked to pay something for that which they can get for nothing, decline to be so idiotic. If the alleged new sub- stance, named by its inventor or dis- coverer "radium" can be cheaply ob-
tained, and if it will go on shining like the sun. practically for ever, alas! for the gas men and the illuminating elec- tricians! It is asserted that Madame Currie, of the Paris Municipal School of Phy- sics, has had her name enrolled on the books of the French Academy of Sciences, and has received a reward of four thousand francs in recognition of her having discovered radium; and if this be so there is good reason to suppose that at least some fact of genuine scientific interest has been dis- closed. Radium is probably a more luminous substance than any which has yet been isolated or compounded by the chemist or physicist; but whe- ther it can take the place of gas or the electric light for household illu- mination is a question which, for the present, must be held strictly among the things unproved. It is well known, in connection with the appliances for rendering the xrays visible, that cer- tain salts of the metal uranium pos- sesses a power of absorbing some kinds of light rays and of emitting them after excitation. Madame Currie has for some time been devoting attention to the problem of determining the true cause of this property of uranium salts, and it is said that she has suc- ceeded in separating out a metal simi- lar in some respects to bismuth, which in its power of emitting rays of light is several thousands of times stronger than the original salts of uranium from which it was obtained. From this again she produced a compound having some of the properties of the metal barium, but this on being heat- ed gave out visible rays of light. The lady had prepared delicate tests by which to measure the intensity of the illuminant but she found that fast photographic plates were sensitive enough for her purpose. The account in the American paper already quoted says that a good impression was ob- tained on the rapid plate in about 15 minutes. With bright ordinary day light it is practicable to take a snap shot with a rapid plate in something less than the fiftieth part of a second. This suggests that the light emitted by the substance isolated or compoun- ded by Madame Currie cannot be more powerful than about one-fifty-thou- sandth part of the illumination inside of a hand camera when the aperture is opened on a bright day. Yet the 'Cincinatti Enquirer,' which seriously prints the details of this interesting scientific experiment introduces them by asserting that wben Professor Langley opened the leaden box con- taining the radium which was sent to him— the strange substance "lit up the room as completely as though the rays of the sun had penetrated into the place," which was a photographic dark room. A light which required fifteen minutes to impress a fast pho- tographic plate in Paris was quite enough— when it got to Washington— to give the effect of briliant daylight in a professor's darkened study. Something here certainly requires exact scientific explanation.