ON EVAPORATION" AND DISSOCIATION. 
151 
Reduction and Arrangement of Results. 
Vapour-Pressures .-—The vapour-pressures experimentally determined, and also 
those calculated by the formula log p = a -V ha} c/3'', are given in the following 
table:— 
Tem- 
Pressure. 
perature. 
Still 
method. 
A. 
B. 
C. 
D. 
Mean. 
Calculated. 
Ap, 
O 
0 
3-44 
3-44 
3-49 
+ -05 
10 
7-26 
7-26 
7-39 
•13 
20 
14-50 
14-5 
14-78 
•28 
30 
27-60 
27-6 
28-13 
•53 
40 
50-20 
50-2 
51-12 
•92 
50 
87-20 
87-2 
89-00 
1-80 
60 
147-00 
147-0 
148-97 
1-97 
70 
239-00 
2.39-0 
240-44 
1-44 
80 
376-00 
376-0 
375-31 
- 0-69 
90 
574-00 
574-0 
568-11 
- 5-89 
100 
842-5 
842-5 
835-89 
- 6-61 
110 
1206-0 
1206 
1198-2 
- 7-8 
120 
1683-0 
1683 
1677-0 
- 6-0 
130 
2295-0 
2288 
2293 
2295-9 
+ 2-9 
140 
3074-0 
, , 
3074 
3080-3 
6-3 
150 
4059-0 
4053 
4023 
4052 
4057-1 
5-1 
160 
5264-0 
5264 
5253-4 
- 10-6 
170 
6695-0 
, , 
6695 
6697-8 
+ 2-8 
180 
8.387-0 
8365 
838.3 
8418-8 
35-8 
190 
10466-0 
, ^ 
10466 
10445 
- 21 
200 
12S28-0 
12691 
12801 
12809 
+ 8 
210 
15575-0 
15575 
155.39 
- 36 
220 
18671-0 
18711 
18679 
18667 
- 12 
230 
22161-0 
22 ()k 
22183 
221.54 
22230 
+ 76 
240 
26208-0 
26102 
26227 
26194 
26263 
69 1 
250 
30779-0 
30809 
30785 
30807 
22 ' 
260 
.36110-0 
35955 
362^ 
3610.3 
35908 
- 195 1 
1 
1 
In calculating the mean the greatest weight has always been given to the deter¬ 
minations with the largest quantity, A. The constants employed were calculated 
from pressures at 20°, 80°, 140°, 200°, and 260°. The constants for the formula a,re—■ 
a - 4-479370. 
log h = r-3915059. log a = 0-001641423. 
log c = 0-5509601. log /3 = 1-99657025. 
c is negative. ^ = ^°c — 20. 
Determinations of the vapour-pressures of propyl alcohol by the statical method are 
given by Konowalow. They are reproduced in the following table, together with 
the pressures calculated from our constants for Biot’s formula. It is to be noticed 
that our results at these temperatures were obtained by the dynamical method. 
