(adhe 
176 Profs. Hagen and Rubens on some Relations 
observed emission of platinum-foil is obtained by means of 
the equation 
w,;=wy(1 + at + Bi), 9. Se 
in which 
w,=0°154 
a2=0°0024 
8 =0-00000383. 
This is proved in Table VI., the first column of which 
contains a few temperatures in Celsius degrees. The second 











Tasue Vi, 
: i ; 
1 2 3 4 / £ 6 Z 
Bee : Specific resist- | Conduc- i eeaaaraae vie. ”! Observed sir ue 
Cree ance | tivity 7-23 black | deflexion (100-_R 
= | wy=w,(1 tat +827)! «ze. | (100—R)=—— . a ) 
degrees. |" % ° Nx, || body y¢. observed. 
170 0-233 431 3-49 196 66 | 3:36 
220 0°260 3°84 3°68 261 9°6 3°68 
300 0:312 3°22 4:04 366 15:7, 4°29 
600 0:559 1:79 5°40 758 42°8 5°65 
900 0-900 Pa 6:86 1150 796 6:93 
1200 1°33 Oval 8°34 1540 128-0 8°32 
1500 1:85 0:540 9°84 1940 189°5 9-78 





shows the respective specific resistances, computed from 
formula 5; the third, the corresponding conductivity «,, and 
the fourth the emission-power of the employed platinum, 
computed from the equation | 
dome 
| Wwe 
The fifth column gives the radiation y; of the “‘ black body,” 
as derived, for the respective temperature, from the radiation 
of the black body at 170° by linear extrapolation. The sixth 
column contains the observed galvanometer-deflexions a for 
the emission of the heated platinum-foil. These numbers 
were derived from Table V. by interpolation. By forming 
the ratio of the corresponding numbers of columns 6 and 5, 
and by multiplying it by 100, one obtains the “observed ” 
emission-powers, given in column7. The agreement of these 
numbers with the ‘‘ computed” ones of column 4 is the more 


