Page:Popular Science Monthly Volume 58.djvu/131

Rh nitrous air being received by two measures of this without any increase of dimensions. Now as common air takes about one half of its bulk of nitrous air before it begins to receive any addition to its dimensions from more nitrous air, and this air took more than four half measures before it ceased to be diminished by more nitrous air, and even five half measures made no addition to its original dimensions, I conclude that it was between four and five times as good as common air. It will be seen that I have since procured air better than this, even between five and six times as good as the best common air that I have ever met with.

TOOK a small retort with a long narrow neck, which I bent over a lamp so that the end of the neck could be held under a bell-jar full of water standing in a vessel of water. Into the retort I put two ounces of slightly fuming acid of nitre, the weight of which was to that of distilled water in the proportion of 131,607 to 100,000. I added two ounces one dram of mercury and heated it slightly to hasten the solution.

As the acid was very strong, the effervescence was lively and the decomposition very rapid. I received the air which was liberated in different bell-jars in order to be able to tell the differences which might be found between the air at the beginning and at the end of effervescence, supposing there should be such. When the effervescence had stopped and all the mercury had dissolved, I continued to heat the material in the same apparatus. Soon boiling appeared in place of the effervescence, aud while the boiling went on air was produced in almost as great abundance as before. I continued this until all the fluid had passed out, either by distillation or as elastic vapors of air, and nothing was left in my retort save a white salt of mercury, in a pasty form, dry rather than wet, which began to grow yellow on its surface. The quantity of air obtained up to this point was about 190 cubic inches; that is to say, about four quarts. All this air was of a uniform sort and was nowise different from what M. Priestley has called nitrous air.

On continuing the experiment, I noticed that from the mercury salt there arose red fumes like those of the acid of nitre; but this phenomenon did not last long and soon the air in the empty part of the retort