126 
PROFESSOR W. RAMSAY AND DR, S. YOUNG 
Pressure :—Reading on high-pressure gauge, 199‘35. Temperature of gauge, 12'7°. 
Patio of total volume of gauge tube to that of compressed air, the correction for the 
meniscus of the mercury in the gauge being applied, 2(P008 : 1 . Patio corrected for 
temperature and pressure and for temperature at which gauge was filled =20‘003 
atmospheres =15,202 — 115^=15,087 mms. Add difference in heights of mercury in 
gauge and in experimental tube =76 mms., 15,087 + 76 = 15,163 mms. From this 
example an idea may be gathered as to the methods of reduction employed, and of the 
corrections introduced. 
6. We now proceed to give results corrected by the method above explained. 
Pressures of Vapour. 
Vapour used as jacket. 
T. 
Number of 
observations. 
Mean pressure in mms. 
Chlorobenzene. 
89°85 
4 
1,188 
110 0 
3 
2,356 
130-05 
3 
4,344 
Bromobenzene. 
130-10 
8 
4,309 
140-25 
6 
5,701 
Methyl salicylate. 
150-0 
3 
7,353 
Bromobenzene. 
150-65 
6 
7,400 
Aniline. 
151-40 
3 
7,605 
160-25 
4 
9,334 
Methyl salicylate. 
161-0 
3 
9,647 
Aniline. 
161-6 
6 
9,775 
Methyl salicylate. 
171-0 
3 
12,170 
Aniline. 
171-75 
5 
12,288 
Methyl salicylate. 
180-95 
3 
15,078 
Aniline. 
181-4 
6 
15,184 
Methyl salicylate. 
189-8 
4 
18,102 
Bromonaphthalene. 
199-3 
3 
21,851 
Methyl salicylate. 
200-0 
4 
22,167 
Bromonaphthalene. 
209-75 
3 
26,639 
Metbyl salicylate. 
210-05 
4 
26,894 
Bromonaphthalene . . . 
219-9 
3 
31,990 
219-9 
3 
31,967 
Methyl salicylate. 
220-45 
4 
32,425 
Bromonaphthalene. 
225-05 
4 
34,972 
230-35 
5 
38,416 
232-6 
5 
39,821 
234-7 
5 
41,485 
235-85 
5 
42,186 
236-8 
5 
42,864 
237-95 
5 
43,645 
239-0 
9 
44,673 
240-1 
6 
45,579 
241-25 
5 
46,386 
. 
242 25 
4 
47,095 
„ . 
242-8 
4 
47,088 
242-95 
3 
47,832 
(Apparent critical point) 
243-1 
? 
47,850 
7. As it is impossible to distinguish between liquid and gas at the critical point, so 
it is impossible to give the vapour-pressure at the critical point. The pressures 
* Correction for divergence of dry air from Boyle’s law. 
