appendix. 347 
Air would be comprefled with more than 
feventy two Columns of Water, each equal 
to the Weight of the Atmofphere, fo that 
the Air would be compreffed into ^d part 
of its natural Bulk, in which cafe the Den. 
fity of that Air would be to Water as i to 
1 1 . (^4. When the Air is compreffed with the 
Weight of ninety nine Columns of Water at 
the Depth of 32 6^7 Feet, or half a Mile and 
<^27 Feet, then its Deniity will be |th of 
Water ; at a hundred and ninety nine Co- 
lumns Depth, or a Mile and Quarter, and 
a hundred and thirty two Feet, its Denfity 
will be -^th of Water ; and at three hundred 
and ninety nine Columns depth, or two 
Miles and half wanting fifty three Feet, its 
Denfity will be i of Water. 
23. I have compreffed Air with a Weight 
equal to 37. 44 Atmofpheres in the follow- 
ing manner, viz. I tookaGlafs Tube which 
was clofed at one End, the Length of its 
Cavity 4. 06 Inches, its Diameter o. 16. be- 
ing firfl: counterpois'd in a Scale, and then 
filled with Water, the Weight of the Wa- 
ter it contained was one Dram and fix Grains. 
The open End of this Tube I immerfed in a 
(mall Viol, at the Bottom of whioh was fome 
Mercury 
I 
