ON EVAPORATION AND DISSOCIATION. 
157 
Addendum. 
(Added February II, 1889.) 
The conclusions of Konowalow (Joe. cit.) regarding the nature of the so-called 
hydrate of propyl alcohol have been fully confirmed. It was found that the compo¬ 
sition of the mixture, which boiled constantly under a pressure of 198'7 mms., differed 
from tliat obtained under the ordinary atmospheric pressure ; the lower the pressure, 
the higher is the percentage of water in the distillate. 
The boiling-points of four different samples of the mixture were determined under 
pressures varying from 746 to 762 mms. ; corrected to 760 mms., the temperatures 
observed were 87°'65, 87°'85, 87°’9, and 87“‘6—mean 87°‘75. 
The vapour-pressures were determined by both the dynamical and statical methods, 
with the following results : — 
Dynamical Method. 
Pressure. 
Temperature. 
Pressure. 
Temperature. 
Pressure. 
Temper,iture. 
mms. 
O 
mms. 
O 
mms. 
O 
5-75 
- 0-9 
38-9 
27-4 
1 269-8 
635 
6'75 
+ 1-25 
46-0 
.30-2 
1 304-3 
66-1 
8T5 
4-1 
57-1 
33-6 
347-9 
69-1 
9-0 
5-5 
66-8 
36-3 
358-7 
69-8 
9-2 
5-85 
78-9 
39-2 
405-7 
72-6 
lOT 
7-2 
92-55 
42-2 
466-4 
75-9 
12-55 
9-8 
109-5 
45-3 
526-6 
78-9 
15-8 
13-3 
123-5 
47-65 
590-9 
81-9 
19-05 
16-1 
143-7 
50-5 
658-8 
84-5 
22-75 
18-7 
167-4 
53-6 
760-6 
87-9 
27-55 
21-7 
200-6 
57-4 
32-75 
24-6 
232-0 
60-3 
1 
Statical Method. 
Temperature. 
Pressure. 
Pre.S3ure read from curve 
constructed from results by 
dynamical method. 
O 
mms. 
mms. 
13-3 
16-6 
15-7 
15-1 
18-2 
17-7 
15-7 
19-2 
18-45 
25 
35-5 
33-8 
30 
47-9 
45-4 
40* 
83-8 and 83-95 
81-1 
50 
142-1 
138-9 
60 
231-7 
226-5 
70 
365-4 
361-5 
75 
452-7 
450-0 
* The following pi'essures were also observed at 40° in the vapour-density tube:—83‘o, 82'35, 82'55, 82'2.i). 
