This order of attraction is very different from that obtaining at the red heat; in which temperature charcoal and iron have a much stronger affinity for oxygene than either phosphorus or hydrogene.[180]
The smallest quantity of oxygene given in the different analyses of nitrous oxide just detailed, is thirty five hundred parts; the greatest proportion is thirty-nine.
Taking the mean estimations from the most accurate experiments, we may conclude that 100 grains of the known ponderable matter of nitrous oxide, consist of about 36,7 oxygene, and 63,3 nitrogene; or taking away decimals, of 37 oxygene to 63 nitrogene; which is identical with the estimation given in [Research I].
XV. Observations on the combinations of
Oxygene and Nitrogene.
During the decompositions of the combinations of oxygene and nitrogene by combustible bodies, a considerable momentary expansion of the acting substances, and the bodies in contact with them is generally produced, connected with increased temperature; whilst light is often generated to a great extent.
Of the causes of these phænomena we are at present ignorant. Our knowledge of them must depend upon the discovery of the precise nature of heat and light, and of the laws by which they are governed. The application of general hypotheses to isolated facts can be of little utility; for this reason I shall at present forbear to enter into any discussions concerning those agents, which are imperceptible to the senses, and known only by solitary effects.
Analysis and synthesis clearly prove that oxygene and nitrogene constitute the known ponderable matter of atmospheric air, nitrous oxide, nitrous gas, and nitric acid.
That the oxygene and nitrogene of atmospheric air exist in chemical union, appears almost demonstrable from the following evidences.
1st. The equable diffusion of oxygene and nitrogene through every part of the atmosphere, which can hardly be supposed to depend on any other cause than an affinity between these principles.[181]
2dly. The difference between the specific gravity of atmospheric air, and a mixture of 27 parts oxygene and 73 nitrogene, as found by calculation; a difference apparently owing to expansion in consequence of combination.