ON EVAPORATION AND DISSOCIATION. 
323 
Pressure of bromo- 
naphthalene. 
Temperature. 
Volume of 1 gramme. 
Pressure. 
Vapour density. 
mms. 
O 
c.cs. 
mms. 
295-95 
239 
39-95 
22,020 
18-08 
29-38 
28,243 
19-17 
23-48 
33,232 
20-40 
17-63 
40,209 
22-46 
14-73 
44,361 
24-36 
11-85 
49,432 
27 17 
10-42 
51,849 
29-46 
8-982 
54,282 
32 63 
7-552 
56,808 
37-08 
6-838 
57,307 
40-59 
6-127 
58,328 
44-52 
5-696 
58,568 
47-67 
V apour-pressure 
= 58,672 
299-65 
239-5 
11-85 
49,634 
27-09 
10-42 
52,301 
29-24 
8-982 
54,568 
32-49 
7-552 
56,992 
36-99 
6-838 
57,836 
40-25 
6-127 
58,703 
44-27 
5-410 
58,776 
50-08 
30.3-35 
240 
39-95 
22,100 
18-05 
29-38 
28,361 
18-72 
23-48 
33,454 
20-30 
17-63 
40,651 
22-26 
14-73 
44,677 
24-24 
11-85 
49,761 
27-04 
10-42 
52,406 
29-21 
8-982 
54,993 
32-27 
7-552 
57,071 
36-98 
6-127 
58,751 
44-28 
5-410 
59,590 
49-45 
4-697 
59,775 
56-77 
3-984 
60,038 
65-84 
C. The weight of this portion was 0'00221 gramme. It was ascertained from 
measurements of the volume occupied by the vapour at 230° and 240°. At 230° the 
change of volume was from 1*0245 cub. centim. to 0'6019 cub. centim. ; the product 
ol pressure and volume was constant, and gave for the weight 0 , 002211 gramme ; at 
240°, with the same change of volume, the weight was 0'002206 gramme. The value 
taken was 0'00221 gramme. The error can hardly be more than 0'5 per cent. 
The following determinations were made 
2 T 2 
