Analyfis of the Air . 171 
for 2 or 3 minutes : As foon as the flame 
was out, I marked the height of the water 
z z > after which the water would for 20 
or 30 hours continue riling a great deal a» 
bove zz. 
Sometimes when I would pour violent- 
ly fermenting liquors, as aquafortis, 
on any materials, I fufpended the aquafortis 
in a viol at the top of the glafs veflel z z 
a a , in fuch manner, that by means of a 
firing, which came down into the veffel 
x x, I could by inverting the viol pour the 
aquafortis on the materials, which were in 
a veflel on the pedeftah 
I Aiall now proceed to give an account of 
the event of a great many Experiments, 
which I made by means of thefe inftru- 
ments, which I have here at flrft defcribed, 
to avoid the frequent repetition of a defcrip- 
tion of ’em. It is confonant to the right 
method of philofophifing, flrft, to analyfe 
the fubjeft, whofe nature and properties we 
intend to make any refearches into, by a 
regular and numerous feries of Experiments: 
And then by laying the event of thofe Ex- 
periments before us in one view, thereby 
to fee what light their united and concur- 
ring evidence will give us. How rational 
this 
