fame 'Experiments -made with an Air-pump. 64c 
"Exp. l 11. The receiver cemented ] 
to the pump -pi ate, — J 
E*x-p. l hi. The receiver unce-% 
mented, wiped clean from 
the cement;, and put on the - 
pump-plate, with a little oil 
round the outlide, — 
Exp. liv. The receiver .put on a] 
leather foaked in oil and tallow, i 
Degree's of exhauftion when the pump 
had been worked 
Five minutes; 
according to 
Ten’ minutes,; 
according; to 
O 
Barom. 
gage- 
Pear- 
gage* 
1 — 
Barom, 
g a ge* 

! Pear- 
gage* 
43 ° 
CO 
0 
0 
430 
360 
502 
360 
502 
360 
502 
320 
3 2 3 
500 
This laft experiment feemed very extraordinary; for 
after having worked the pump for five minutes only, the 
barometer-gage indicated a degree of exhauftion of 5 o 2 ; 
hut by working the pump five minutes more, it indicated 
a lefs degree of exhauftion, viz. 3 23. This effect I have 
obferved to happen more than once. 
1 
Degrees of exhauftion when the pump 
had been worked 
■ 
; 
r 
P 4 ve minutes ; 
according to 
Ten minutes; 
according to 
i 
Barom. 
gage* 
Pear- 
gage. 
1 
Barom. 
gage* 
Pear- 
gage* 
Exp. lv. Receiver put on a leather 1 
foaked in water for one night, J 
Exp. lvi. Receiver put on a leather -j 
foaked for one night in a mixture { 
of two parts water and one fpi- j 
rit of wine, — — » J 
47 
48 
380 
3 o° 
6 3 
5 ° 
8000 
1200 
Vol. LXVII. 4 O The 
