st down
the small Tube, till I perceived the Quicksilver to rise within it to a
mark that I had plac'd just an inch from the top; and immediately clapping
on a small piece of cement that I had kept warm, I with a hot Iron seal'd
up the top very fast, then letting it cool (that both the cement might grow
hard, and more especially, that the Air might come to its temper, natural
for the Day I try'd the Experiment in) I observ'd diligently, and found the
included Air to be exactly an Inch.

Here you are to take notice, that after the Air is seal'd up, the top of
the Tube is not to be elevated above the superficies of the Quicksilver in
the box, till the surface of that within the Tube be equal to it, for the
Quicksilver (as I have elsewhere prov'd) being more heterogeneous to the
Glass then the Air, will not naturally rise up so high within the small
Pipe, as the superficies of the _Mercury_ in the box, and therefore you are
to observe, how much below the outward superficies of the _Mercury_ in the
box, that of the same in the Tube does stand, when the top being open, free
ingress is admitted to the outward Air.

Having thus done, I permitted the _Cylinder_, or small Pipe, to rise out of
the box, till I found the surface of the Quicksilver in the Pipe to be two
inches above that in the box, and found the Air to have expanded it self
but one sixteenth part of an inch; then drawing up the small pipe, till I
found the height of the Quicksilver within to be four inches above that
without, I observed the Air to be expanded only 1/7 of an inch more then it
was at first, and to take up the room of 1-1/7 inch: then I raised the Tube
till the Cylinder was six inches high, and found the Air to take up 1-2/9
inches of room in the Pipe; then to 8, 10, 12. &c. the expansion of the Air
that I found to each of which Cylinders are set down in the following
Table; where the first row signifies the height of the _Mercurial
Cylinder_; the next, the expansion of the Air; the third, the pressure of
the _Atmosphere_, or the highest _Cylinder_ of _Mercury_, which was then
neer thirty inches: The last signifies the force of the Air so expanded,
which is found by substracting the first row of numbers out of the third;
for having found, that the outward Air would then keep up the Quicksilver
to thirty inches, look whatever of that height is wanting must be
attributed to the Elater of the Air depressing. And therefore having the
Expansion in the seco