I introduced into a jar of the capacity of 20 cubic inches, containing 11 cubic inches of nitrous oxide, over mercury, a small quantity of fine iron wire twisted together, and having affixed to it a particle of cork. On throwing the focus of a burning glass on the cork, it instantly inflamed, and the fire was communicated to the wire, which burnt with great vividness for some moments, projecting brilliant white sparks. After it had ceased to burn the gas was increased in volume rather more than three tenths of an inch. The nitrous acid tests were introduced, but no acid appeared to have been formed. On exposing the gas to water, near 4,2 cubic inches were absorbed: the 7,1 remaining appeared to be pure nitrogene. From this experiment it is evident that iron at the temperature of ignition, is capable of decomposing nitrous oxide; likewise that it is incapable of burning in it when it contains more than three fifths nitrogene. I attempted to inflame zinc in nitrous oxide, in the same way as iron; but without success. By keeping the focus of a burning glass upon some zinc filings, in a small quantity of nitrous oxide, I converted a little of the zinc into white oxide, and consequently decomposed a portion of the gas. XI. _Combustion of Pyrophorus in Nitrous Oxide._ Pyrophorus, which inflames in nitrous gas, and atmospheric air, at or even below 40°, requires for its combustion in nitrous oxide a much higher temperature. It will not burn in it, or alter it, even at 212°. I have often inflamed pyrophorus in nitrous oxide over mercury, by means of a wire strongly heated, but not ignited. The light produced by the ignition of pyrophorus in nitrous oxide is white, like that produced by it in oxygene: in nitrous gas it is red. When pyrophorus burns out in nitrous oxide, a little increase of the volume of gas is produced. Strontian lime water agitated in this gas becomes clouded; but the quantity of carbonic acid formed is extremely minute. I have never made any delicate experiments on the combustion of pyrophorus in nitrous oxide. XII. _Combustion of the Taper in Nitrous Oxide._ It has been noticed by different experimentalists, that the taper burns with a flame considerably enlarged in nitrous oxide: sometimes with a vivid light and crackling noise, as in oxygene; at other times with a white central flame, surrounded by a feeble blue one. My experiments on the combustion of the taper in nitrous oxide, were chiefly made with a view to ascertain the cause of the double flame. When the inflamed taper is introduced into pure nitrous oxide, it burns at first with a brilliant white light, and sparkles as in oxygene. As the combustion goes on, the brilliancy of the flame diminishes; it gradually lengthens, and becomes surrounded with a pale blue cone of light, from the apex of which much unburnt charcoal is thrown off, in the form of smoke. The flame continues double to the end of the process.