Page:Experimental researches in chemistry and.djvu/223

208 by reason of this peculiarity, have any sensible degree of volatility, in conjunction with water or its vapour, conferred upon them at ordinary temperatures, that the following experiments were made. It is well known that a theory of meteoric stones has been founded on the supposition that the earthy and metallic matter found in them had been raised in vapour from similar matter upon the earth's surface; which vapours, though extremely attenuated and dilute at first, gradually accumulated, and by some natural operation in the upper regions of the atmosphere became condensed, forming those extraordinary masses of matter which occasionally fall to us from above. The theory has in its favour the remarkable circumstance, that, notwithstanding many substances occur in meteoric iron and stones, yet there is none but what also occur on this our earth ; and it also has a right to the favouring action of water, if there be such an action; because vaporization is one of the most important, continual, and extensive operations that go on between the surface of the globe and the atmosphere around it.

ln September 1826, several stoppered bottles were made perfectly clean, and several wide tubes closed at one extremity, so as to form smaller vessels capable of being placed within the bottles, were prepared. Then selected substances were put into the tubes, and solutions of other selected substances into the bottles: the tubes were placed in the bottles so that nothing could pass from the one substance to the other, except by way of vaporization. The stoppers were introduced, the bottles tied over carefully and put away in a dark safe cupboard, where, except for an occasional examination, they have been left for nearly four years, during which time such portion of the substances as could vaporize have been free to act and produce accumulation of their specific effects.

No. 1. The bottle contained a clear solution of sulphate of soda with a drop of nitric acid,—the tube, crystals of muriate of baryta. One half or more of the water has passed by evaporation into the tube, and formed a solution of muriate of