on some of the leading doctrines of caloric , &c. 351 
Table II. 
Observed elasticity of aqueous vapour compared with the ratios. 
Temp. 
Calcul. 
Force. 
Expert. 
Temp. 
Calcul. I 
Force. 
Expert. 
Dalton. 
Betanc. 
Robison.! 
210° 
28.9 
28.9 
210° 
28.9 
28.9 
28.84 
28.8 
28.65 
200 
23.5 
23.0 
220 
35-54 
35-54 
34-99 
35.80 
190 
19.0 
19.0 
230 
43-36 
43.10 
4 >- 7 S 
45-5 
44 - 7 ° 
180 
15.2 
15.16 
240 
52.46 
51.70 
49.67 
54.90 
170 
12.07 
12.05 
250 
62.95 
61.90 
58.21 
66.80 
160 
9.50 
9.60 
260 
74.91 
72.30 
67-73 
80.17 
80.30 
* 5 ° 
7.42 
7.58 
270 
88.39 
86.30 
77-85 
94.10 
140 
5 - 75 . 
5-77 
280 
103.41 
101.90 
88.75 
105.12 
105.90 
130 
4.42 
4 - 3 6 
290 
119.95 
120.15 
100.12 
120 
3 37 
3 33 
300 
> 37-94 
139.70 
1 1 1.81 
1 10 
2.55 
2 -45 
3 ->° 
157.25 
161.30 
123-53 
100 
1.92 
1.86 
320 
> 777 ° 
135.00 
90 
>•43 
1.36 
80 
1.06 
1.01 
Temp. 
Betanc. 
Robison. 
70 
0.77 
0.726 
60 
0.56 
0.516 
32* 
0.0 
0.0 
5 ° 
0.40 
0.36 
50 
0.12 
40 
0.28 
0.25 
80 
0.81 
0 82 
3 ° 
0.20 
0.19 
100 
1.65 
1.60 
20 
0.14 
0.14 
120 
2.95 
3.00 
10 
0.098 
140 
5 .00 
5->5 
0 
0.068 
160 
9.00 
8.65 
180 
14.00 
14.05 
1 
200 
22.50 
22.62 
The rule on which the preceding table is formed, may be 
expressed in a manner better fitted to give directly the elastic 
force corresponding to any given temperature moderately 
distant from 212 0 . It becomes also more accurate. 
Let r= the mean ratio between 210® and the given tem- 
perature; n = the number of terms (each of io°) distant 
from 210 0 ; F = the elastic force of steam in inches of 
mercury. 
Then, Log. of F = Log. 28.9 ± n. Log. r; the positive 
sign being used above, the negative below 210®. 
