Experimenting in this way I was never, however, able to decompose more than one third of the quantity of nitrous oxide employed; not only the nitrogene evolved, but likewise the sulphuric and sulphureous acids produced, stopping the combustion. I found that sulphur in a state of vivid inflammation, when introduced into a mixture of one fourth nitrogene, and three fourths nitrous oxide, burnt with a flame very much enlarged, and of a vivid rose color. In one third nitrogene, and two thirds nitrous oxide, it burnt feebly with a yellow flame. In equal parts of nitrous oxide and nitrogene, it was instantly extinguished. Sulphur burnt feebly, with a light yellow flame, when introduced ignited into a mixture of 5 nitrous gas, and 6 nitrous oxide. In one third nitrous oxide, and two thirds nitrous gas, it was instantly extinguished. From many circumstances, I am inclined to believe that sulphur is incapable, at any temperature, of slowly decomposing nitrous oxide, so as to burn in it with a blue flame, forming sulphureous acid alone. It appears to attract oxygene from it only when intensely ignited, so as to form chiefly sulphuric acid, and that with great rapidity, and vivid inflammation. VII. _Decomposition of Nitrous Oxide by Sulphurated Hydrogene._ _a._ Though nitrous oxide and sulphurated hydrogene do not act upon each other at common temperatures, yet they undergo a mutual decomposition when mingled together in certain proportions, and ignited by the electric spark. From more than twenty experiments made on the inflammation of sulphurated hydrogene in nitrous oxide, I select the following as the most conclusive and accurate. The temperature at which they were made was from 41° to 49°. _b._ _E._ 1. About 35 measures of nitrous oxide were fired with 10 of sulphurated hydrogene; the expansion during inflammation was very great, and the flame sky-blue. Immediately after, the gases filled a space equal to 48 nearly. White fumes were then formed, and they gradually contracted to 40. On the admission of a little strontian lime water, a slight absorption took place, with white precipitation; and the volume occupied by the residual gas nearly equalled 37. On admitting nitrous gas to these, no perceptible diminution took place. _E._ 2. 20 sulphurated hydrogene, with 25 nitrous oxide, could not be inflamed. 30 nitrous oxide, with 22 sulphurated hydrogene, could not be inflamed. 35 nitrous oxide, with 20 sulphurated hydrogene, inflamed with vivid blue light, and great expansion. After the explosion, the gases filled exactly the same space as before the experiment; no white fumes were perceived, and no farther contraction occurred. On the addition of strontian lime water, a copious precipitation, with diminution, took place; and the residual gas filled a space nearly equal to 35½.