Page:Popular Science Monthly Volume 9.djvu/586

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THE POPULAR SCIENCE MONTHLY.

The same means will serve in storing solar heat, and, if need he, shipping it to a distance. We have barely outlined the idea, but certain we are that at the proper time the scientific man will appear who shall discover a practical method of doing this.

The sun, as it would appear, will be the fuel of the future, and one might say that this was foreseen by the great encyclopædic scholar of the middle ages, Dante, when in his incomparable poem he said, "Guarda il calor del sol che si fa vino"—"Look at the sun's heat which changes into wine"—as though he meant to say, into all that is force, all that is life, all that is light.—Revue des Deux Mondes.

 

THE REVIVED THEORY OF PHLOGISTON.
By WILLIAM ODLING, M. B., F. R. S.

FULLERIAN PROFESSOR OF CHEMISTRY, ROYAL INSTITUTION.

IN 1781-'83, Cavendish showed that when inflammable air or hydrogen, and dephlogisticated air or oxygen, are exploded together in certain proportions, "almost the whole of the inflammable and dephlogisticated air is converted into pure water," or, as he elsewhere expresses it, "is turned into water."

On June 24, 1783, the experiment of Cavendish was repeated on a larger scale and in a somewhat different form by Lavoisier, who not only confirmed the synthesis of the English chemist, but drew from it the conclusion—at first strongly contested, then rapidly acknowledged, and since never called into question—"that water consists of inflammable air united to dephlogisticated air," or that it is a compound of hydrogen and oxygen.

This conclusion, so opposite to his own preconception on the matter, Lavoisier subsequently confirmed by an analysis of water. He found that iron, heated to redness and exposed to the action of water-vapor, became changed, by an abstraction of oxygen from the water, into the self-same oxide of iron procurable by burning the metal in oxygen gas—the other constituent of the water, namely, its hydrogen, being freely liberated.

With the demonstration by Lavoisier of the composition of water began the triumph of that antiphlogistic theory which he had conceived, in a necessarily imperfect form, so far back as 1772, or before the discovery of oxygen, and had brought to completion by the aid of every successive step in pneumatic chemistry, achieved by himself or by others.

In 1785, the relationship to one another of hydrogen and water being then conclusively established, Berthollet declared himself a convert to the new theory of combustion put forward by his countryman.