nnv inflammable Air or Gafs , Sec. 407 
ftances inftead of combining the two airs firft feparated 
from them. 
APPENDIX. 
IN the foregoing paper I attempted to give a compa- 
rative view of the explofive force of gunpowder and in- 
flammable explofive air, which latter I had found to be 
fo far fhort of the explofive force of gunpowder as not 
to conceive any well grounded hope that it could ever 
become a fubftitute to this ingredient. 
At that time I had not yet tried the effeCt of very pure 
dephlogifticated air combined with that inflammable air, 
into which I had found that vitriolic aether is changed in 
an inftant. 
I muft acknowledge, that I had but fmall expectations 
from the force of thefe two airs combined ; for as I had 
always obferved, that aether air combined with com- 
mon air is lefs brifk in taking fire, and lefs powerful in 
exploding, than inflammable air extracted from the vi- 
triolic or marine acid, I thought that the fame aether air 
combined with very pure dephlogifticated air would alfo 
H h h 2 be 
