f 284 ]j 
tube exactly divided, and fees at 
otice, without any fhaking, how 
much of the two airs is deftroyed. 
Jf this method is purfued~ accu- 
rately, and if the fame interval of 
time is obferved between joining 
the two airs and letting them up, 
the refult will, however, be found 
‘different in different experiments, 
as ‘Dr. See? make no 2 aaa 
I mite a great many experimented 
to find out the reafon of this differ- 
ence; but this tafk I leave to Abbe 
Fontana, who commenced his en- 
quiries on this fubject prior to me. 
I will only relate one of my own, 
which will fhew the reader what 
refult he may expect from his expe- 
riments, though performed in the 
moft regular manner. 
