ick power of the Air, both Experimentally and
Hypothetically calculated, according to its various Dimensions._

The dimensions The height The Mercurial The sum or What they
of the included of the Cylinder difference ought to
Air. Mercurial added, or of these be according
Cylinder taken from two to the
counter- the former. Cylinders. Hypothesis.
pois'd
by the
Atmosphere.
---------- ---------- ---------- ---------- ----------
12 29 + 29 = 58 58
13 29 + 24-11/16 = 53-11/16 53-7/13
14 29 + 20-3/16 = 49-3/16 49-5/7
16 29 + 14 = 43 43-1/2
18 29 + 9-1/8 = 38-1/8 38-2/3
20 29 + 5-3/16 = 34-3/16 34-4/5
24 29 0 = 29 29
48 29 - 14-5/8 = 14-3/8 14-1/2
96 29 - 22-1/8 = 6-7/8 7-2/8
192 29 - 25-5/8 = 3-3/8 3-5/8
384 29 - 27-2/8 = 1-6/8 1-7/16
576 29 - 27-7/8 = 1-1/8 1-5/24
768 29 - 28-1/8 = 0-7/8 0-[7-1/4]/8
960 29 - 28-3/8 = 0-5/8 0-[5-4/5]/8
1152 29 - 28-7/16 = 0-9/16 0-10/16

From which Experiments, I think, we may safely conclude, that the Elater of
the Air is reciprocal to its extension, or at least very neer. So that to
apply it to our present purpose (which was indeed the chief cause of
inventing these wayes of tryal) we will suppose a _Cylinder_ indefinitely
extended upwards, [I say a _Cylinder_, not a piece of a _Cone_, because, as
I may elsewhere shew in the Explication of Gravity, that _triplicate_
proportion of the shels of a Sphere, to their respective diameters, I
suppose to be removed in this case by the decrease of the power of Gravity]
and the pressure of the Air at the bottom of this _Cylinder_ to be strong
enough to keep up a _Cylinder_ of _Mercury_ of thirty inches: Now because
by the most accurate tryals of the most illustrio