396 Dr? ingenhousz’s Account of a 
Nitre is compofed of two different ingredients, viz. an 
acid, called from its peculiar nature the nitrons acid , and the 
vegetable alkali. Neither of thefe two ingredients are capa- 
ble of inflammation; nay, they even extinguifh actual lire. 
When they are both combined and conftitute the neu- 
tral fait we fpeak of, they have not, even by their coali- 
tion in one body, acquired an inflammable quality, for 
nitre may be made red-hot in a crucible without [hew- 
ing the leaft appearance of inflammation, not even when 
a red-hot ftone or piece of iron is thrown into it. But if 
any common combuftible fubftance, as wood, charcoal, 
or fuch like, is thrown into the melted nitre, a flame 
iflues with a kind of explofion, though only at the very 
place where the two fubftances come into contact. 
The fame flame and explofion is obferved when cold 
nitre is thrown upon a combuftible body, in a ftate of 
real ignition, on a piece of red-hot charcoal for inftance. 
The true reafon of this wonderful phenomenon has 
not been confklered hitherto with that degree of atten- 
tion it deferves, and could not have occurred to any body 
before our modern philofophers had difcovered the na- 
ture of various kinds of air, and the manner of ex- 
tracting them from bodies. 
Inflam- 
