Chap, i.] Great Difcevery of Mr. Cavendijh. 



when diflblved in acids, yielded it by means of- heac 

 alone i his mode of extracting it was by fubjecting the 

 filings of the different metals in vacuo to the action 

 of a burning glafs. 



The next remarkable, and perhaps the moft impor- 

 tant difcoyery, was that of Mr. Cavendifh, which has 

 explained to us the nature, and compofition of water. 

 Mr. Cavendifh was led to this great difcovery by the 

 experiment of Mr. Warltire, related by Dr. Pricftley, 

 in which it was found, that on firing a mixture of com- 

 mon and inflammable air by the electric fpark, a lofs 

 of weight always enfued, and that the infide of the vef- 

 fel in which it was fired became always moid or dewy, 

 though ever fo carefully dried before. On repeating 

 the experiment, Mr. Cavendifh did not perceive the 

 diminution of weight which Mr. Warkire fuppofed to 

 take place, but the latter effect was completely exem- 

 plified. In profecuting the experiment, it appeared, 

 that it was only the pure or empyreal part, that is about 

 one-fourth, of the common air which was confumed, 

 and the water produced was perfectly taftelefs and 

 pure ; on mixing empyreal with inflammable air in a 

 due proportion, and pafllng through them an electric 

 fpark, the whole portion loft its elafticity, and was con- 

 denfed into water. 



Mr. Cavendifh fmrfued his experiments with re- 

 markable fuccefs, to afcertain the conflituent principles 

 of phlogifticated air, or that which conftitures the im- 

 pure and unrefpirable portion of the atmofpheric air, 

 and by pafiing the electric fpark through common air, 

 and through a certain mixture of empyreal and phlo- 

 gifticated airs, he was able totally to condenfe the lat- 

 ter, and to afcertain its constituent principle to be the 

 fame with that of nitrous acid, with (as he then thought) 

 a fmall portion of inflammable matter. In this latter 



VOL. I. E b opinion, 



