108 
MEASUREMENT OF HIGH TEMPERATURES. 
[bull. 
Table 14. — Constancy of temperature along axis of boiling tube, etc. — Continued. 
Height above 
bottom of mbe. 
t. 
e. 
T. 
Time. 
Remarks. 
Cm. 
°c. 
Micro- 
volts. 
°0. 
f 13 
19.0 
4487 
444.0 
3 45 
1 
J 11 
In vapor. < ^ 
l 9 
19.0 
19.0 
19.0 
4496 
4511 
4529 
444.7 
445.9 
447.4 
Violent ebullition. Liquid at 
r 8 
19.0 
4597 
452.7 
8.5 cm . 
In liquid. ■{ „ 
j 6 
19.0 
19.0 
4657 
• 4669 
457.4 
458.4 
I 5 
19.0 
4423 
439.1 
J 
f 13 
19.0 
4492 
444.4 
5 15 
1 
J 11 
In vapor. <{ 
19.0 
19.0 
4502 
4513 
445.2 
446.1 
I 9 
f 8 
1 ? 
19.0 
19.0 
4550 
4609 
448.9 
453.6 
Violent ebullition. Liquid at 
19.0 
4669 
458.6 
8.5 cra . 
1 
In liquid. < 6 
li 
19.0 
4669 
458.4 
| 
19.0 
19.0 
4478 
3900 
443.4 
396.9 
. 
5 30 
16.0 
4206 
449.6 
|,11 30 a. in. 
1 
17.2 
19.3 
19.2 
20.3 
19.8 
14.8 
4198 
4190 
4180 
4185 
4183 
4203 
449.3 
449.8 
449.0 
449. 8 
449.8 
448.2 
12 10 p.m. 
2 30 p. m. 
3 00 p.m. 
5 30 p. m. 
7 30 p. in. 
|, 9 00 a.m. 
Check observations made with 
a special thermo-couple dur- 
ing the progress of the above 
* measurements. Hotjunction 
just above surface of ebulli- 
19.4 
4171 
448.5 
12 00 p. m. 
tion. 
18.4 
4183 
448.8 
2 15 p.m. 
18.7 
4187 
449.3 
5 30 p. m. 
J 
By plane of ebullition, an expression frequently to be used, I ref< I 
merely to the mean surface of the agitated liquid. Above this there | 
a similar well defined plane of condensation, and the zone of constai j 
temperature lies between these planes, nearer the lower. 
The data taken as a whole show that for l cm or 2 cm above the plane < 
ebullition the variation of temperature is not more than two or thrca 
degrees from the boiliug point. These changes are produced by rel; 
tively great differences in the intensity of ebullition. The use of thic 
asbestos jackets increases the height of the space of constant temper: 
ture. As was the case with mercury, the zone of ebullition is sharpl 
marked both above and below the surface of the liquid, and its heigl 
depends very materially on the violence of the boiling. The tube du 
ing ebullition is apt to be very dark brown, so that it is sometimes difl 
cult to discern the boiling surface at all. It is well, therefore, to mar 
its position beforehand. Taking the above results as a whole, it aj 
pears that just above the surface of ebullition the temperature is coi 
stant for an indefinite period of time, and that it does not differ froi 
the boiling point of sulphur more than a degree at most. 
Exploration for constancy of temperature; zinc. — In Table 15 I giv 
(762) 
