recollect, with that which I had feen at Mr. Lavoifier's; fo that I had no doubt but that my process, though fomewhat different from his, had anfwered perfectly well. Confidering this flame with attention, I thought it very much resembled that which is produced by a mixture of about one-third inflammable air, and two-thirds nitrous air; and concluded, that it was probably composed of them both; the nitrous acid forming nitrous air, by feizing upon the phlogiston of the fpirit of wine; and there being a redundancy of inflammable matter, fufficient to render the air partially inflammable. In the directions to make nitrous ether, I was cautioned to pour the spirit of nitre upon the spirit of wine, and by no means to pour the spirit of wine upon the spirit of nitre. But though this method of mixing these liquids may not answer the purpose of making nitrous ether, it answered very well for the production of air, and was a very useful variety in the process. It is neceffary, however, that the unexperienced operator fhould be upon his guard in these experiments. The spirit of nitre fhould be much diluted, and the quantity of any liquid inflammable matter matter should be very small, just sufficient to cover the surface of it: otherwife, though the mixture may exhibit no alarming appearance at first, it will, in a little time, become very black, beginning at the furface; the phial will then be filled with red fumes, the air will be generated in a prodigious torrent, and, unless the tube through which it is tranfmitted be fufficiently wide, and the veffel in which the mixture is made be very ftrong, the whole will be exploded with great violence. Of this I have feen but too many inftances; and fometimes when I had thought that my experience had taught me fufficient precaution. Befides, all oily matters become extremely vifcid, by mixing with spirit of nitre; and this vifcid matter getting into the tube, ftops it up, and much increases the hazard of an explosion. But to recur to the experiments. Having poured a very little spirit of wine upon a quantity of diluted fpirit of nitre in a glafs-phial, with a ground ftopple and tube, a great quantity of air was presently produced. When a candle was dipped into this air, it was extinguished; but in going out was furrounded with a flight blue or green flame, but hardly more than is perceived in nitrous air. Almoft one-half of this produce of air was rea dily abforbed by water, and precipitated lime in lime-water; and I doubt not but that, in the fubfequent experiments, as well as in this, a great proportion of the air produced in this manner was fixed air. The remainder was nitrous, almost as ftrong as any. Upon air produced in this manner from oil of turpentine, I happened to make a few more experiments, fome of which are not a little remarkable. When I used the strongest spirit of nitre in this process, it was very difficult to get much air, on account of the fuddenness of the effervefcence; but a great quantity of air is eafily produced by diluting the fmoking spirit of nitre with an equal quantity of water. At one time, however, when I had heated this mixture pretty much, and it had yielded a great deal of air, though I withdrew the candle, the air continued to be produced fafter and fafter for about a minute. It then came quite in a torrent; all the oil of turpentine was thrown out of the phial, and the spirit of nitre only left in it. This is likewife the cafe with other fimilar mixtures; fo that when it is neceffary to apply heat, it should be done very gradually and cautioufly, and the air fhould never be generated very faft, unless the purpose of the experiment require it, and the be upon his guard accordingly. operator When When I received this air in water, it extinguished a candle, and did not diminish common air. When received in quickfilver, it still extinguished a candle; but as it went out the third or fourth time, it was furrounded with a bluish flame, as large as that of the candle. And happening, at one time, to apply more heat than I intended when the air was received in water (and in confequence of it, the air was produced very fuddenly) I examined it immediately, and a candle burned in it with an enlarged flame, though not remarkably fo. It fhows, however, that in this procefs alfo, as well as in the procefs for making phlogisticated nitrous air, the property of its admitting a candle to burn with an enlarged flame depends, in a great meafure, upon the time at which the experiment is tried after the air is produced, and upon other delicate circumftances. A quantity of this air, received in water, was about half-absorbed in one night. By agitation it appeared to be absorbed not fo readily as fixed air, nor with fo much difficulty as nitrous air, but in a medium between both. When this air was reduced to about one-eighth of its original bulk, it was diminished by nitrous air. But this is the cafe with all the kinds of air that will bear the experiment, and even with nitrous air itself, as I have observed former publication. in my At the time that I made the preceding experiments with oil of turpentine, I had no limewater at hand; and therefore only judged that part of the produce was fixed air, by the manner in which it was abforbed by water. But, lefs certain as this teft is, a perfon much used to experiments of this kind, will be able to apply it with fufficient certainty in most cafes. However, repeating this experiment, when I had procured the glafs-phials with groundstopples and tubes, I found that the greatest part of this air was unquestionably fixed air, precipitating lime in lime-water, as much as any fixed air whatever, and that the remainder was ftrongly nitrous. Attempting at this time alfo, to receive the air in quickfilver, a good deal of the vapour of the spirit of nitre came over; and, diffolving the quickfilver, made the produce of air almost wholly-ni trous. I observed, at one time, when I had produced this air in a phial with a ground-stopple, that after the first part of the process, in which no heat was applied, the water rushed back into the phial. Upon this I applied the flame of a candle to the diluted mixture, and getting a fecond K |