76 
MEASUREMENT OF HIGH TEMPERATURES. 
Table 5.— Constancy of temperature in the later form of zinc boiling-point appar 
time series — Continued. 
Date. 
Time. 
h. 
No. of 
thermo- 
couple. 
020- 
Ts. 
T zn . 
Remarks. 
h.m. 
' 
June 11, 1884 
35 
45 
0.83 
1.00 
19 
19 
2815 
970 
915 
50 
1.08 
(23) 
2806 
970 
915 
58 
1.22 
19 
2828 
974 
920 
5 10 
15 
1.42 
1.50 
19 
19 
2824 
972 
916 
25 
30 
1.67 
1.75 
19 
19 
2784 
960 
907 
June 14, 1884 
3 23 
0.00 
19 
2811 
970 
914 
3 47 
0.40 
19 
2839 
970 
1)21 
June 21, 1884 
4 35 
41 
o.oo 
0.10 
23 
23 
999 
1002 
939 
942 
2907 
55 
0.33 
23 
2915 
1002 
943 
5 06 
0.52 
23 
2919 
1004 
944 
22 
0.78 
23 
2935 
1010 
950 
June 25, 1884 
3 55 
0.00 
23 
2809 
970 
914 
4 15 
0.33 
23 
2809 
970 
914 
4 40 
0.75 
23 
2829 
974 
920 
4 55 
1.00 
23 
2829 
974 
920 
5 06 
1.18 
23 
2829 
974 
920 
5 18 
1.38 
23 
2780 
960 
907 
In the experiments made on the 15th and 18th of Apr. 1 the cha 
were obviously too small. Hence we fail to discern a boiling poii 
the first instance and obtain irregular results in the second, in bot 
which cases the zinc vapor is superheated. In the next series 
charge of zinc is much increased and the results are regular. The v 
of T zn is slightly low, a result which may be attributed to varioui 
traneous causes, such as slight corrosion or zincification of the the] 
couple, polarization errors in the measuring apparatus, etc. In thi 
in the following series of experiments of the 30th of April, the terni 
ature of the cold junction, in consequence of its unavoidable proxiu 
to the furnace, rises as high as 70°. Otherwise both series are as < 
plete as any we made. The effect of charging the furnace with f 
coal does not chill the retorts perceptibly, and the experiments i 
carried to an end without accident. In the series made on the 12t 
May, as well as in all subsequent series, the cold junction was kej 
a low temperature (ca. 15°) by submerging it in a current of run; 
water. The values for T zn found are lower than usual. The work << 
both on the 19th of May and on the 21st of May was interrupter 
breakage of the central tube. There resulted a diminution of the ch 
of zinc, in consequence of leakage, and the thermoelement soou i 
cated the presence of superheated zinc vapor. No boiling point is 
cernible. The experiments on the 26th of May were again termin 
at an early stage of progress by an explosion, due to stoppages in 
efflux pipe for the zinc vapor. Both the elements No. 18 and N< 
(730) 
