476 PROFESSOR W. RAMSAY AND DR. S. YOUNG ON THE INFLUENCE OF 
Temperature. 
Pressure. 
Temperature. 
Pressure. 
m llims. 
millims. 
0 
4'600 
- 9 
2 365 
-1 
4-281 
-10 
2190 
— 2 
3-983 
-11 
2-027 
-3 
3703 
-12 
1-875 
-4 
3-441 
-13 
1-734 
— 5 
3-196 
-14 
1-602 
— 6 
2-966 
-15 
1-480 
— 7 
2-752 
-16 
1-366 
-8 
2-552 
36. The vapour-pressures of ice and water may be taken as equal at 0°. The 
vapour-pressure of ice at —l c is calculated as follows 
(1.) Difference between vapour-pressure of water at 0 C and at — 1°, =4’600 —4"281 
= 0’319 millim. 
(2.) This difference, multiplied by the ratio between 0° and — 1°, =0'319xlT30 
= 0'361 millim. 
(3.) Vapour-pressure of ice at 0° — difference of pressures between (Band —l c , = 4'600 
— 0'361 = 4"239 millim. 
In this manner the theoretical vapour-pressures of ice from 0° to —16“ were 
calculated. 
37. In the table below, under column A, are given the theoretical vapour-pressures 
of ice, calculated as above, and B gives results calculated by means of Regnault’s 
empirical formula E for temperatures between 0° and —32°. 
Temperature. 
Pressure. 
A. 
B. 
millims. 
millims. 
°0 
4-600 
4-600 
- 1 
4-239 
4-263 
_ 2 
3-903 
3 941 
- 3 
3-587 
3 "644 
- 4 
3-292 
3-368 
- 5 
3-016 
3113 
— 6 
2 - 757 
2-876 
— 7 
2-516 
2'65S 
- 8 
2-292 
2-455 
- 9 
2-082 
2-267 
-10 
1-886 
2-093 
-11 
1-704 
1-933 
-12 
1-534 
1-783 
-13 
1-376 
1-646 
-14 
1-229 
1-518 
—15 
1-093 
1-400 
-16 
0-966 
1-290 
