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the weight of the atmofphere, is one part in 10870 
of it’s whole bulk.* 
The famous Florentine experiment, which fo many 
Philofophical writers have mentioned as a proof of the 
incompreffibility of water, will not, when carefully 
confidered, appear fufficient for that purpofe : for in 
forcing any part of the water contained in a hollow 
globe of gold through its pores by preflure, the figure 
of the gold muff be altered ; and confequently, the 
internal fpace containing the water, diminifhed ; but* 
it was impoffible for the gentlemen of the academy 
del Cimento to determine, that the water which was 
forced into the pores and through the gold, was ex- 
actly equal to the diminution of the internal fpace by 
the preflure. 
* If the compreffibility of the water was owing to any air that 
it might ftill be fuppofed to contain, it is evident that more air 
muft make it more cotnprejjible ; I therefore let into the ball a bubr 
ble of air that meafured near Jb. of an, inch in diameter, which 
the water abforbed in about four days ; but I found upon trial 
that the water was. not more comp refled, by. twice the weight 
of the atmofphere,. than before,. 
The campreffion of the glafs in this experiment, by the equals 
and contrary forces adting within and without the ball, is not. 
fenfible : for the compreffion of water in two balls, appears to 
beexadtly the fame, when the, glafs of one is more than twice 
the thicknefs of the glafs of the other. . And the weight of an 
atmofphere, which I found would comprefs mercury in one of 
thefe balls but \ part of a divifion of the tube, comprefles water; 
in the fame ball 4 divifions and 
CIV; Am 
