_EXPERIMENTS and OBSERVATIONS on the COMBINATIONS of NITROUS OXIDE._ I. _Combination of Water with Nitrous Oxide._ _a._ The discoverer of nitrous oxide first observed its solubility in water; and it has since been noticed by different experimentalists. Dr. Priestley found that water dissolved about one half of its bulk of nitrous oxide, and that at the temperature of ebullition, this substance was incapable of remaining in combination with it.[153] [153] Experiments and observations, vol. ii. pag. 81. _b._ I introduced to 9 cubic inches of pure water, i. e. water distilled under mercury, 7 cubic inches of nitrous oxide, which had been obtained over mercury, from the decomposition of nitrate of ammoniac, and in consequence was perfectly pure. After they had remained together for 11 hours, temperature being 46°, during which time they were frequently agitated, the gas remaining was 2,3; consequently 4,7 cubic inches had been absorbed. And then, 100 cubic inches, = 25300 grains of water, will absorb 54 cubic inches, = 27 grains, of nitrous oxide. _c._ The taste of water impregnated with nitrous oxide, is distinctly sweetish; it is softer than common water, and, in my opinion, much more agreeable to the palate. It produces no alteration in vegetable blues, and effects no change of color in metallic solutions. _d._ Thinking that water impregnated with nitrous oxide might probably produce some effects when taken into the stomach, by giving out its gas, I drank, in June, 1799, about 3 ounces of it, but without perceiving any effects. A few days ago, considering this quantity as inadequate, I took at two draughts nearly a pint, fully saturated; and at this time Mr. Joseph Priestley drank the same quantity. We neither of us perceived any remarkable effects. Since that time I have drank near three pints of it in the course of a day. In this instance it appeared to act as a diuretic, and I imagined that it expedited digestion. As a matter of taste, I should always prefer it to common water. _e._ Two cubic inches of pure water, that had been made to absorb about 1,1 cubic inches of nitrous oxide; when kept for some time in ebullition, and then rapidly cooled, produced nearly 1 of gas. Sulphur burnt in this gas with a vivid rose-colored flame. In another experiment, in which the gas was expelled by heat from impregnated water, and absorbed again after much agitation on cooling; the residuum was hardly perceptible, and most likely depended upon some gas which had adhered to the mercury, and was liberated during the ebullition. Hence it appears that nitrous oxide is expelled unaltered from its aqueous solution by heat.