f 37' 3 



XXIII. Experime?2ts on Air, 

 By Henry Cavendifn, EJq. F,R.S. and A.S, 



Read June 2, 17S5. 



IN a Paper, printed in the laft volume of" the Philofophical 

 Tranfaclions, in which I gave my reafons for thinking that 

 the diminution produced in atmoipheric air hy phlogifticatioii 

 is not owing to the generation of fixed air, I laid it feemed mofl 

 likely, that the phlogiftication of air by the elei^rlc fpark was 

 owing to the burning of fome inflammable matter in the appa- 

 ratus ; and that the fixed air, fuppofed to be produced in that 

 procefs, was only feparated from that inflammable matter by 

 the burning. At that time, having made no experiments 011 

 the fubje£t myfelf, I was obliged to form my opinion from 

 ■thofe already publifhed ; but I now find, that though I was 

 right in fuppoling the phlogiflication of the air does not pro- 

 ceed from phlogilion communicated to it by the electric fpark, 

 and that no part of the air is converted into fixed air ; yet that 

 the real caufe of the diminution is very different from what I 

 fufpe6led, and depends upon the converfioii of phlogifticated 

 air into nitrous acid. 



The apparatus ufed in making the experiments was as follows. 

 The air through which the fpark was intended to be palled, was 

 confined in a glafs tube M, bent to an angle, as in fig. i. (tab. 

 XV.) which, after being filled with quickfilver, was inverted 

 into two glaffes of the fame fluid, as in the figure. The air to 



be 



