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[ 178 ] 
by the cold, runs plentifully down its fides in water.^ 
After a veffel of water had boiled till all the air bub- 
bles were driven out of it, I turned upon its mouth 
a large glafs that lay in the water j the bubbles that 
afcended under the glafs remained in the upper parr 
of it, and forced out the water it before contained, 
and then the elaftic matter in the glafs overturned 
it, againft the fide of the veffel, and burfting out 
afcended to the top in one large bubble, upon which 
the fteam on the furface appeared to be much in- 
creafed. Now this fliews that the matter contained 
in thofe bubbles, which is quite tranfparent, being a 
very rare and homogeneous fluid, appears afterwards 
like fleam when it is mixed with the air. But I 
thought I fhould make a more decifive experiment, 
if I could obferve the effedls of very hot fleam con- 
veyed under boiling water. Therefore when an 
aeolipilc had boiled till the air was all driven out of 
the water it contained, without taking it off the fire, 
I immerfed its pipe into a veffel of water which had 
juft been boiled, and immediately the fteam, which 
iffued from the pipe, rofe up in very large bubbles 
through the water, and made it feem to boil violently. 
Then I held a large glafs of cold water, fo that the 
pipe of the boiling ceolipile was immerfed into it. At 
firft none of thele large bubbles appeared ; for the, 
fteam being then condenfed by the cold water, was 
mixed with it, making a very uncommon noife j 
but as foon as the water in the glafs - grew very hot 
this noife ceafed, and the fleam being no longer 
condenfed rofe in large bubbles, and made the wa- 
ter .appear to boil with great violence. 
Thdc 
