| 
THERMO-ELECTRIC PROPERTIES OF CHARCOAL AND CERTAIN ALLOYS. 337 
In Table X. will be found deflections of the M-N circuit ee the corre- 
sponding temperatures of the heated junction. 
TABLE X. 
° Temperature. M-N Deflections. 
146° C. 0 
142-2 32°9 
147-9 344 
168:2 40 
181:2 43:2 
From the observations of Table X. we deduce the formula 
6,= const. + '25947¢; 
and therefore, oe = "25947. 
The AuFe, line thus determined is given on Plate XXI, Its equation is 
y= +'149t—41-06. 
The iron and gold lines (after Tarr) are laid down on the diagram. The line 
of the alloy resembles that of gold more than that of iron, as might be expected 
from the small quantity of iron present. 
Platinum-Silver Alloy, containing 35 per cent. of Silver. 
To make observations with a wire of this alloy we found it convenient to 
join it in a circuit with a palladium wire (the same which Professor Tarr used 
in determining the palladium line on his diagram), instead of the usual N wire. 
Otherwise the arrangement and method were the same as before. The N wire 
of the thermometric circuit, and the platinum-silver wire of the thermo-electric 
circuit, were joined to the same terminal of the galvanometer. ‘The temperature 
of the beakers was almost constant at 13°4° C. For a short time it was 13°45°, 
| and again for a short time 13°5°. The observations are given in Table XI. 
won. XXVIII. PART II, - 4T 
