486 PHILOSOPHICAL TRANSACTIONS. [ANNO 1784. 



related an experiment of Mr. Warltire's, in which it is said that, on firing a mix- 

 ture of common and inflammable air by electricity, in a close copper vessel hold- 

 ing about 3 pints, a loss of weight was always perceived, on an average about 2 

 grs., 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 

 1 used held more than Mr. Warltire's, namely, 24,000 grs. 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 -t-th of 

 a grain, and commonly none at all. However, 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 di- 

 minished 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, 



Common air. Inflammable Diminution. Air remaining Test of this Standard, 

 air. after the ex- air in first 



plosion. method. 



1 1.241 686 1.555 055 



1.055 642 1.413 063 



706 647 1.059 066 



423 612 811 097 03 



331 476 855 339 27 



206 294 912 648 58 



In these experiments the inflammable air was procured from zinc, as it was in 

 all my experiments, except where otherwise expressed : but I made 2 more ex- 

 periments, to try whether there wa~ any difference between the air from zinc and 

 that from iron, the quantity of inflammable air being the same in both, namely, 

 0.331 of the common ; but I could not find any difference to be depended 

 on between the two kinds of air, either in the diminution which they suffered by 

 the explosion, or the test of the burnt air. 



From the fourth experiment it appears, that 423 measures of inflammable air 

 are nearly sufficient to completely phlogisticate 1000 of common air; and that 

 the bulk of the air remaining after the explosion is then very little more than -j-ths 



* Dr. Priestley, I am informed, has since found the experiment not to succeed.— Orig. 



