on some of the leading doctrines of caloric, &c. 34,7 
between contiguous measures, was to adopt the astronomical 
plan of multiplying observations and deducing truth from the 
mean. It is essential to heat with extreme slowness and 
circumspection, the vessels, A, B, C. One repetition of the 
experiment occupies on an average 7 hours. 
Table L 
The elastic force of the vapour of water in inches of mercury. 
Temp. 
Force. 
Temp. 
Force. 
Temp. 
Force. 
Temp. 
Force 
Temp. 
Force. 
Temp. 
Force. 1 
H° 
0.170 
US* 
2.820 
* 95 ° 
21.100 
2 4 2° 
53.600 
270 
86.300 
295.6 
1 30.400 1 
32 
0.200 
120 
3.300 
200 
23.600 
245 
56.340 
271.2- 
88.000 
295 
129.000 
40 
0.250 
125 
3.830 
205 
25.9OO 
245.8 
57.100 
273-7 
91.200 
297.1 
133.90° 
5 o 
0-360 
130 
4366 
210 
28.880 
248.5 
60.400 
275 
93.480 
298.8 
137.400 
55 
0.416 
1 35 
5.070 
212 
30.000 
250 
61.900 
275.7 
94.606 
300 
139.700 
60 
0.516 
140 
5 - 77 ° 
216.6 
33 - 4 °° 
251.6 
63.500 
277.9 
97.800 
300.6 
140.900 
6 5 
0.630 
145 
6.600 
220 
35 * 54 ° 
254.5 
66.700 
279.5 
1 01.600 
302 
144.300 
70 
0.726 
150 
7 - 53 ° 
221.6 
36.700 
255 
67.250 
280 
101.900 
3 ° 3-8 
147.700 
75 
0.860 
>55 
8.500 
225 
39. no 
257-5 
69.800 
281.8 
104.400 
3 °S 
150.560 
80 
I.OIO 
160 
9.600 
226.3 
40.100 
260 
72.300 
283.8 
107.700 
306.8 
1 54.400 
85 
1.170 
165 
10.800 
230 
43.100 
260.4 
72.800 
285.2 
112.200 
308 
157.700 
90 
1.360 
170 
12.050 
230.5 
43.500 
262.8 
75.9°° 
287.2 
I I4.8OO 
310 
161,300 
95 
1.640 
175 
13 - 55 ° 
2 34*5 
46.800 
264.9 
77.900 
289 
118.200 
3 H -4 
164.800 
100 
1.860 
180 
15.160 
235 
47.220 
265 
78.040 
290 
I2O.I5O 
312 
167.000 
io 5 
2.100 
185 
16.900 
238.5 
50.300 
267 
81.900 
292.3 
I23. IOO 
Another expert. 
110 
2.456 
190 
19.000 
240 
51.700 
269 
84.900 
294 
I26.7OO 
312® 
1 1 ° 5-5 
JU-- 
The apparatus employed in obtaining these results, has 
the peculiar advantage over all others, that the mercurial 
column is never heated. It is the concurrent opinion of all 
chemical philosophers, that caloric travels downwards in 
liquids with extreme slowness and difficulty. Indeed, Count 
Rumford's experiments led him to infer that heat could not 
descend in fluids at all. 
It is evident that in my constructions, figures 1, 2, and 
g, only that small portion of quicksilver, within the vessels 
Z z 
MDCCCXVIIL 
