In Dr. Priestley’s last volume of experiments is related an experiment of Mr. Warltire’s, in which it is said that, on firing a mixture of common and inflammable air by electricity in a close copper vessel holding about three pints, a loss of weight was always perceived, on an average about two grains, though the vessel was stopped in such a manner that no air could escape by the explosion. It is also related, that on repeating the experiment in glass vessels, the inside of the glass, though clean and dry before, immediately became dewy; which confirmed an opinion he had long entertained, that common air deposits its moisture by phlogistication. As the latter experiment seemed likely to throw great light on the subject I had in view, I thought it well worth examining more closely. The first experiment also, if there was no mistake in it, would be very extraordinary and curious; but it did not succeed with me; for though the vessel I used held more than Mr. Warltire’s, namely, 24,000 grains of water, and though the experiment was repeated several times with different proportions of common and inflammable air, I could never perceive a loss of weight of more than one-fifth of a grain, and commonly none at all. It must be observed, however, that though there were some of the experiments in which it seemed to diminish a little in weight, there were none in which it increased. In all the experiments, the inside of the glass globe became dewy, as observed by Mr. Warltire; but not the least sooty matter could be perceived. Care was taken in all of them to find how much the air was diminished by the explosion, and to observe its test. The result is as follows, the bulk of the inflammable air being expressed in decimals of the common air: ------+-----------+----------+-------------+------------+-------- | | |Air Remaining|Test of this| Common|Inflammable|Diminution| after the | Air in the |Standard Air | Air | | Explosion |First Method| ------+-----------+----------+-------------+------------+-------- 1 | 1.241 | .686 | 1.555 | .055 | .0 | 1.955 | .642 | 1.423 | .063 | .0 | .706 | .647 | 1.059 | .066 | .0 | .423 | .612 | .811 | .097 | .03 | .331 | .476 | .855 | .339 | .27 | .206 | .294 | .912 | .648 | .58 ------+-----------+----------+-------------+------------+---------