4 MiIcROGRAPHIA.’ 
_ in the box, till the furface of that within the Tube be equal to it, for 
the Quickfilver (as I have elfewhere prov'd.) being more heterogene- 
ous to. the Glais-then the Air, will not naturally rife ‘up fo high within 
the {mall-Pipe,as the firperficies of the Afercury in the box 5,arid ‘therefore 
youare toobferve, how much below the outward {uperficies of the 
_ Mercury in the box, that of the fame in the Tube does ftand, When the 
top beingopen, free ingrzfs is admitted to the outward Aith! 2/2 101¥ 
Having thus done, I permitted the Cylinder, or {mall Pipe, |tolrifé ovit 
of the box, till I found the furface of the Quickfilver in the Pipe to:b 
two inches above that inthe box, and found the Airto have’ expanded 
_ it felf but one fixteenth part of an inch; then drawing up the. {malt 
pipe, till Ifound the height of the Quickfilver within to nfo . Anglige 
above that without, Iobferved the Air to be expanded only 4 ree inch 
more then it was at firft, and totakeuptheroom of 17 inch: then I 
raifed the Tube till the Cylinder was fix inches high, and found the Air 
to takeup 12 inches of room in the Pipe; then to8, 18c42. ce. 
the expanfion of the Air that I found to each of which Cyli ders are 
fet down in the following Table; where the firft row igi the 
height of the Mercurial Cylinder 5 the nextthe expanfion ofthe Air 5 
the third, the preffure of the Atmofphere or the highelt QAnder of 
Mercury, which was then _neer thirty inches : The laft fignifies the force 
of the Air fo expanded which is found by fubftracting the firft row of 
numbers out of the third; for having founds that the outward Air would 
then keep up the Quickfilver to thirty inches, look whatever of that 
height is wanting muft beattributed to the Elater of the Aird refling. 
And therefore having tHe*Expanfion in the ond row,and th height of 
223 
the fubjacent Cylinder of, Mercury in the firftp and the greatelbheight of 
the Cylinder of Mercury, which of it felf counterballances the whole 
preflure of the Atmofphere ; by fubftracting the numbers of thefirft row 
out ofthe numbers of thecthird, you will kaye the meafure ofthe Cylin- 
ders {gdepreft, and confequently the foree.of the Air,in the (Gyeral Ex- 
| anfions, regiftred. 
D. Of. « 780 Ue 
ts 0g go gee 
* : : : *&: 
2g of fOr oe 
<8 og et 7s 
i . 7 ‘ 
= O2 _ ran | 4 | . 
‘ : ter = s The 
Bed I 
