Analyfis of the Air. 281 
fix'd Hate than thofe of Nitre, they are there- 
fore thrown off with a greater repulfive 
force, by the united action and re-a&ion of 
all thofe ingredients armed each with its 
acid Spirit. 
Experiment CX VIII. 
Which acid Spirits confifting of a volatile 
acid Salt diluted in phlegm do contribute 
much to the force of explofion; for when heat- 
ed to a certain degree, they make a great ex- 
plofion, like water heated to the fame degree, 
as I found by dropping a few drops of Spirit 
of Nitre , oil of Vitriol, water, and fpittle 
on an Anvil ; and then holding over thole 
drops a piece of Iron which had a white heat 
given it ; upon ftriking down the hot Iron 
with a large Hammer, there was a very great 
explofion made by each of thofe liquors : 
I But frothy fpittle, which had air in it, made 
a louder explofion than water 5 which Ihews 
that the vaft explofion of the Nitre and Sal 
Tartar , which are compofed of elaftick air 
particles, included in an acid Spirit, is owing 
to their united force. 
We may therefore from what has been 
faid, with good reafon conclude, that Fire is 
chiefly invigorated by the a&ion and re- ac- 
tion 
