CHANGE FROM THE LIQUID TO THE SOLID STATE ON VAPOUR-PRESSURE. 463 
P' = Pressure of vapour in millimeters of mercury at temperature of room. 
B =Barometric height „ ,, ,, „ 
b = Height of mercury in experimental tube. 
/3 = Height of mercury in trough. 
p T — Pressure of mercury vapour at temperature T. 
T = Temperature of aniline-vapour. 
t = Temperature of room. 
t' =T —t. 
I =6-/3. 
Vapour-pressures of camphor. 
P'. 
B. 
b. 
P- 
lx 0-000181 t’. 
Pr 
P. 
T. 
State. 
95-2 
764-7 
702-8 
27-2 
9-0 
2-9 
94-9 
136-0 
Solid. 
152-6 
645-1 
28-8 
8-7 
4-5 
1521 
149-8 
274-9 
520-0 
31-7 
6-4 
7-9 
274-1 
168-0 
328-9 
760-7 
459-1 
33-3 
33 
9-6 
327-6 
174-6 
351-8 
764-7 
441-3 
33-7 
4-7 
10-0 
350-6 
176-7 
364-8 
760-7 
427-9 
341 
4-4 
10-5 
363-6 
178-3 
Liquid. 
372-5 
414-0 
34-3 
21 
10-6 
370-3 
178-9 
380-0 
406-2 
34-5 
1-9 
10 9 
378-7 
179-5 
387-2 
399-0 
34-8 
1-7 
110 
385-9 
180-3 
394-6 
759-4 
390-0 
35-0 
1-4 
11-3 
393-3 
181-2 
395-3 
760-7 
390-5 
35-0 
1-5 
11-3 
394-0 
181-3 
399-9 
759-4 
384-6 
35-2 
1-3 
11-4 
398-6 
181-9 
402-1 
382-5 
35-2 
1-3 
11-4 
400-8 
182-0 
406'6 
377-8 
35-4 
IT 
11-6 
405-3 
182-6 
408-7 
375-5 
35-4 
1-0 
11-7 
407-4 
182-8 
414-1 
370-0 
35-6 
0-9 
11-9 
412-8 
183-4 
422-4 
363-0 
35-7 
2-6 
12-3 
421-1 
184-5 
595-2 
750-2 
176-7 
40-0 
1-4 
19-7 
593-2 
198-7 
746-3 
207-3 
For the last observation but one the tube was jacketed with the vapour of methyl 
benzoate boiling at 750'2 millims.; the last observation refers to the boiling-point of 
camphor under a pressure of 746‘3 millims. 
7. A graphic representation of the numbers obtained near the melting-point of 
camphor is given in the annexed curves. Curve No. I., Plate 18, gives a general 
representation of the vapour-pressures of camphor. Curve No. II. shows the vapour- 
pressures in the neighbourhood of the melting-point on an enlarged scale. It is to be 
noticed that the curves exhibit considerable irregularity about the melting-point, and 
that a prolongation of the portion above the melting-point would intersect the portion 
below the melting-point, as shown by dotted lines in Curve No. II. 
8. As our anticipations were so far fulfilled we proceeded to investigate the behaviour 
of benzene and of acetic acid. The measurements obtained by means of a barometer- 
tube were not sufficiently accurate for our purpose, and therefore we employed the 
method described in the paper previously referred to, by means of which it was shown 
