194 
MEASUREMENT OF HIGH TEMPERATURES. 
[BULL. 54J 
upper meniscus of the manometer (see Fig. 30) may be read off in cubiq 
centimeters. The volume v in question is then at once determinable 
volumetrically. For if p' and 7?" be the tensions corresponding to th^ 
volumes Vo+v' and v -\-v" for the same mass of air, under constant 
temperature, then 
p'v' — p"v" 
>v 
p" —p' 
The apparatus actually used was a burette of 50 cc capacity, reading! 
to within 0.1 CC , and which had been carefully calibrated. The lowei 
end of this was connected with the flexible hose of the manometer, thl 
upper end with the platinum capillary tubes leading to the stem. B^ 
aid of an interposed stop-cock (see page 170) the quantity of air in this 
system of tubes could be varied at pleasure. In the table following J 
give the results obtained, from which the general character of thli 
measurement may be learned, v and p are the corresponding values 
v' and p' or v" andjp", respectively, and v the zero volume of this se) 
of canals above the fiducial mark. " Length " and " Diameter" refer t4 
the porcelain stem : 
Table 46. — Compensator volumetry. 
No. 
V 
P 
vo 
Length. 
Diam. 
Remarks. 
cc. 
crn. Hg. 
cc. 
cm. 
cm. 
a 
0.30 
77.49 
1.7 
0.8 
The repetition of this series 
leads to practically the 
same result. 
2.30 
38.98 
a 
0.70 
3.50 
66.94 
30.32 
1.6 
0.8 
a 
1.05 
5. 53 
57.40 
22. 27 
1.8 
0.8 
a 
1.57 
9.00 
48.21 
15.42 
1.9 
0.8 
a 
0.27 
16.50 
76.46 
8.31 
1.7 
0.8 
b 
0.30 
15. 40 
76.50 
15.48 
3.45 
32 
0.8 
b 
0.50 
15.40 
75. 16 
15.60 
3.40 
32 
0.8 
1 
0. 12 
3. 05 
75.40 
30. 65 
2.35 
40 
0.8 
0.40 
68.69 
2.28 
40 
0.8 
3. 09 
30.78 
6.00 
31.13 
2.39 
40 
0.8 
Hew adjustment. 
1.02 
76. 59 
8.62 
23.99 
2. 43 
40 
0.8 
1.03 
76.59 
3.85 
32. 75 
2.03 
36 
0.8 
Do. 
0.48 
76.65 
0.58 
76.03 
1.91 
36 
0.8 
4.28 
30. 57 
(848) 
