BAEU8.] 
CALIBRATION OF ELECTRICAL PYROMETERS 
117 
below the boiling point. The temperature in the cases of both bismuth 
and antimony was sufficiently high to partially fuse the porcelain in- 
sulator, and to cause it to stick fast in the central tube. This is a 
great annoyance, because platinum at high white heats has only small 
tensile strength, and is therefore easily pulled apart in the endeavor to 
withdraw the element from the tube. The difficulty is obviated by 
using fire-clay insulators. 
Table 18. — Crucible, Fig. 13, charged with bismuth. 
No. 
t. 
e. 
C20. 
Time. 
17 
° a 
19 
Micro- 
volts. 
8300 
Micro- 
volts. 
8300 
h. m. 
2 00 
19 
10710 
10700 
5 
19 
11340 
11330 
6 
19 
12010 
12000 
7 
19 
12780 
12770 
10 
19 
13670 
13660 
15 
19 
14150 
14140 
20 
The crucible after the last measurement, being fluxed through, began 
to leak, putting an end to the experiment. The value of T would of 
course only be approximate if obtained by using the zinc constants of 
Table 16 for extrapolation. Nevertheless, the continued rapid increase 
of temperature, T, shows that the boiling point has as yet by no means 
been reached. The behavior is therefore in striking contrast to the zinc, 
charged crucible. 
Table VS.— Crucible, Fig. 13, charged unth antimony. 
No. 
t. 
e. 
e u o. 
• 17 
° a 
20 
Micro- 
volts. 
12410 
Micro- 
volts. 
12410 
17 
20 
12730 
12730 
17 
20 
12790 
12790 
17 
20 
12900 
12900 
Time. 
h. m. 
6 42 
45 
Element No. 17 prilled apart on 
withdrawing it, No. 18 substi- 
tuted for it. 
7 25 
30 
32 
18 
22 
12810 
12830 
18 
23 
13210 
13230 
18 
23 
13210 
13230 
18 
23 
13390 
13410 
18 
23 
13520 
13540 
18 
24 
13600 
13640 
Here the remarks already made under bismuth nearly apply. The 
5rucible leaked after the last observation, and the experiment had there* 
(771) 
