OSMOTIC PRESSURES DERIVED FROM VAPOUR-PRESSURE MEASUREMENTS. 301 
good experiment; there may have been liquid left behind on the capillary walls 
which is picked up again when the meniscus reaches it on its downward journey, 
but we have reason to think that this seldom occurs when changing the pressure 
slowly as already described. 
Example of Experiments .—The following experiments are selected from the 
laboratory note-book as a sample of our work with the twin bulb piezometer:— 
Experiment with a Solution of a-Methyl Glucoside at 0° C. 
(Wt. cone. = 54'692 gr. per 100 gr. water.) 
1 
Date. 
Ml 
Time. 
l 
Temperatures of 
Pressure. 
Atmo¬ 
spheres. 
Readings on 
Remarks. 
Bath. 
Appa¬ 
ratus. 
Upper 
capillary. 
Lower 
capillary. 
1911 
July 7 
6.30 p.m. 
— 
_ 
— 
- ■ 
Filled Piezometer VIII. and 
filled up bath with ice. 
„ 8 
7.15 a.m. 
— 
— 
— . 
Filled up with ice. 
7.45 „ 
— 
' - 
— 
— 
8.0 „ 
— 
— 
— 
—■ 
Ran mercury thread into piezo- 
meter and placed in bath. 
9.0 „ 
— 
— 
— - 
— 
Placed piezometer in apparatus 
(B) and joined up (the dome 
was previously cooled in ice). 
9.40 „ 
5-383 
6-960 
17-01 
26-l s 
410-8 
9.55 „ 
5-381 
6-920 
17-01 
— 
408-1 
Note that 5°-490 on the bath 
10.5 „ 
5-382 
6-917 
17-01 
— 
408-0 
Beckmann = 0° • 23 C. 
10.15 „ 
5 • 382 
6-916 
17-01 
— 
407-8 
10.25 „ 
5-384 
6-916 
17-01 
26-2 
407-8 
10.53 „ 
5-382 
6-912 
57 "83 
26-2 5 
251-0 
11.3 „ 
5-382 
6-912 
57-83 
26" 2 5 
251-0 
11.16 „ 
5 • 384 
6-914 
78-25 
26-3 
173-0 
11.26 „ 
5 • 385 
6-916 
78-25 
26-3 
173-0 
11.42 „ 
- 5-386 
6-917 
102-06 
26-3 5 
83-0 
11.52 „ 
5 • 385 
6-916 
102-06 
26-3 5 
83-0 
12.1 „ 
5-383 
6-914 
57-83 
26-2 5 
251-0 
12.11 „ 
5 "385 
6-915 
57-83 
— 
251-2 
12.21 „ 
5-385 
6-915 
57-83 
26-25 
251-2 
12.31 „ 
5-388 
6-919 
17-01 
26-2 
408-0 
12.41 „ 
5-388 
6-919 
17-01 
26-2 
408-0 
12.51 „ 
5-388 
6-919 
17-01 
- 
26-2 
408-0 
