70 
MEASUREMENT OF HIGH TEMPERATURES. 
table, results are given for the ease in which the thermoelement tube 
h i. Fig. 3 ? is simply submerged in liquid. 
Table 2. — Constancy of temperature in the mercury apparatus. 
No. 
1 
T. 
Time. 
Remarks. 
1. m. 
18 
5.1 
357 
2 30 
4.2 
337 
35 
6.6 
7.8 
356 
} Envelope of t hermo-element (tube) submerged in tbe boiling liquid. 
30 | 
8.7 
356 
50 
9.6 
357 
4 5 
J 
10.2 
359 
20 
Envelope above liquid. 
18 
7.2 
7. 1 2 
359 
360 
6 20 
35 
> Apparatus Fig. 3, but with longer central tube dd. 
Eesults irregular and useless; no satisfactory constancy. 
18 
15.0 
17. _' 
342 
357 
3 40 
4 30 
Apparatus Fig. 3, but with inner side of lid and walls heavily lined 
with piaster. 
Results again irregular; no satisfactory constancy, 
18 
9.0 
10.0 
10.8 
353. 6 
357. 5 
357. 5 
12 

10 
20 
1 
1 
11.6 
:;57.2 
30 
1 
)> Apparatus Fig. 3, with central tubo projecting inward only as 
far 
12.6 
13.8 
356. 9 
356. 4 
45 
55 
as the center of figure. Apparatus without feed-pipe. 
14.8 
356. 5 
1 
10 
i 
15.2 
356. 4 
15 
j 
18 
6.8 
354.3 
10 
50 
i 
7.4 
356.8 
11 
5 
i 
8.1 
9.1 
350.6 
356.7 
11 
11 
30 
50 
> Apparatus Fig. 3, completed form. 
10.1 
356.7 
12 
20 
11.2 
356. 7 
12 
55 
Curiously enough, when the walls were lined with an inch coating of 
plaster above the plane of ebullition, although distillation took place 
with great rapidity, the thermo-elemeut did not show the boiling point 
until about one hour had elapsed. Where no feed-pipe is used the tem- 
perature gradually falls as the charge of mercury diminishes in bulk. 
In the final form the negligible differences of temperature, amounting 
(after ebullition has set in) to less than 0.2°, are probably errors of 
measurement. The accuracy of the thermo-electric method is not war- 
ranted within 0.1 per cent. 
Data for the zinc vapor baths.— In digesting the data obtained for the 
variation of temperature in the zinc apparatus, it will be necessary to 
be more circumspect. For this reason we shall exhibit a very complete 
(724) 
