nets) inflammable Air or Gafs , See; 391 
air ; the ready production of fuch inflammable air always 
ready for ufe, w'hen an explofion is intended to be pro- 
duced, may be of fome importance to pbilofophers 
whofe time mult be fpai'ingly taken up. 
Comparative view of the expanding force of exphfive air 
and gunpowder , 
The force of gunpowder has been afcribed by Sir 
Isaac newton and all other philofophers to the hidden 
extrication of an amazing quantity of elaftic permanent 
aerial fluid within a narrow fpace incapable of contain- 
ing it; which quantity ought to be attentively attended 
to, in order to eltimate the comparative power of the 
two fubftances. 
benjamin robins, whofe work, intitled, New Prin- 
ciples of Gunnery , pafles in this country for a ftandard 
book, affirms, that gunpowder, when fired, generates a 
permanent elaftic fluid of 2 5 o times the bulk of the pow- 
der before it was fired. He found, that common air, which, 
is heated by the contaCl of a red-hot iron, expands to 
four times its former bulk. Hence he concludes, that 
the elaftic air, difengaged from gunpowder, muft expand 
alfo to four times its dimenfion; and that it occupies 
about a thoufand times the bulk of the powder in the 
moment of inflammation. 
F f f 2 
The 
