From these observations we learn, that neutro-saline solutions in general, have very feeble attractions for nitrous oxide; and as solutions of green muriate, and sulphate of iron, whether free from nitrous gas, or impregnated with it, possess no action upon nitrous oxide, nitrous gas may be separated from this substance by those solutions with greater facility than nitrous oxide can be separated from nitrous gas, by water or alcohol. Charcoal absorbs nitrous oxide as well as all other gases; and it is disengaged from it by heat. I have as yet found no other solid body, not possessed of alkaline properties, capable of absorbing nitrous oxide in any state of existence. The bodies possessing the strongest affinity for oxygene, the dry sulphites, muriate of tin, the common sulphures, white prussiate of potash, and green oxide of iron, do not in the slightest degree act on nitrous oxide at common temperatures. V. _Action of different Gases on Nitrous Oxide._ _a._ 12 measures of muriatic acid gas were mingled with 7 measures of nitrous oxide at 56°. After remaining together for a minute, they filled a space equal to 19½ measures. When water was introduced to them, the muriatic acid was absorbed much more slowly than if it had been unmingled. In another experiment, when the gases were saturated with water, 9 measures of each of them, when mingled and suffered to remain in contact for a quarter of an hour, filled a space nearly equal to 19; and after the muriatic acid had been absorbed by potash, the nitrous oxide remained unaltered in its properties. From the expansion, it appears most probable that aëriform muriatic acid, and nitrous oxide, have a certain affinity for each other, and that they combine when mingled together; for in the last experiment, the increase of volume cannot be accounted for by supposing that nitrous oxide undergoes less change of volume than muriatic acid, by aëriform combination with water, and that the expansion depended upon the solution of some of its combined water by the muriatic acid. That muriatic acid and nitrous oxide have a slight affinity for each other, likewise appears from the absorption of nitrous oxide by aqueous solution of muriatic acid. Thinking that nitrous oxide might attract muriatic acid from its solution in water, I exposed a minute quantity of fluid muriatic acid to nitrous oxide; but no alteration of volume took place in the gas. _b._ 6 measures of nitrous oxide were mingled with 11 measures of sulphureous acid, saturated with water; after remaining at rest for six minutes, they filled a space nearly equal to 18 measures. Exposed to water, the sulphureous acid was absorbed, but not nearly so rapidly as when in a free state. Sulphur burnt with a vivid flame in the residual nitrous oxide. 7 measures of sulphureous acid were now mingled with 8 of nitrous oxide. They filled a space nearly equal to 15¾, and no farther expansion took place afterwards.