7 oo Col. roy’s Experiments for 
common atmolphere. The fecond, which is divided into 
two fets, contains thofe on air that fuftained a preflure 
lefs than the atmofphere. In the third clafs, a very fhort 
column of quickfilver being employed to confine the 
air, its denfity differed little from that we commonly 
breathe in : this clafs is likewife fubdivided into two fets, 
and it will hereafter be made ufe of to regulate the equa- 
tion depending on the temperature of the air, in the ap- 
plication of the barometer. The fourth and laft clafs of 
experiments, were made on air of the common denfity, 
artificially moiftened by the admiflion, fometimes of 
fteam, and at others of water, into the bulb; it is accord- 
ingly diftinguifhed into two fet 9 , 
table i. Refults of experiments on the expanfion of air, 
whofe mean denfity was equal to 2^ atmofpheres. 
K° 
Height of 
the baro- 
meter. 
Inches of 
quickfilver 
confining 
the air. 
Denlity 
in 
inches. 
Total expan- 
fion of 1000 
equal pans of 
air by 2 1 z °. 
Mean rate 
for each 
degree. 
1 
29.7 
+72. 
101.7 
45*-54 
2.12991 
2 
29.7 
+62.6 
92.3 
423 23 
1.99637 
3 
29.62 
+50.84 
80.46 
412.09 
1.94382 
4 
29.66 
+24.88 
54-54 
439- 8 7 
2.07486 
5 
29.66 
4- 20.05 
49 - 7 i 
443-24 
2.09075 
Mean, 
75-74 
434.00 
2.04717 
T’ ABLE 
