BARU6.) 
PYRO-ELECTRIC PROPERTIES OF ALLOYS. 
147 
The following data were obtained, nomenclature as above: 
Table 35.— Electrical tests for purity. 
Number. 
t 
T 
e ob- 
served. 
e calcu- 
lated. 
aXlO 3 
6X10 6 
+A—0... 
+A—0... 
+A—0... 
20 
18 
17 
100 
358 
448 
+ 68 
+ 345 
+ 447 
68 
335 
446 
777 
554 
This wire A was then fused before the oxy hydrogen blow-pipe con- 
secutively for live minutes each time and tested both for resistance 
and for thermo-electric power after each fusion. The results investi- 
gated range as follows, beiug obtained, of course, from wires drawn and 
softened from the buttons, for each case : 
Table 36. — Electrical tests for purity. 
Treatment. 
Galvanics. 
Tbermo-electrics. 
n 
t 
?X10 6 
St 
Couple. 
T—t 
e 
Before fusion 
After one fusion . . . 
After two fusions. . 
After three fusions . 
913 
707 
723 
710 
23 
23 
23 
23 
1450 
1890 
1810 
1810 
13.5 
13.3 
13.1 
12.9 
+A-0.... 
+A—0.... 
+A-0.... 
+J.-0.... 
358—25 
358 — 25 
358 — 25 
358 — 25 
+330 
+347 
+337 
+■345 
These results give clear evidence of the occurrence of volatilization 
during the whole of the fifteen minutes of fusion before the blow-pipe. 
But the amount of variation (6 per cent.), though large in itself, was not 
relatively so large with reference to the total variation due to alloying (500 
per cent. ) as to be seriously apprehended. Moreover, the button could be 
X>urified by intensely fusing it on lime for some time before alloying it. 
A second set of experiments, unfortunately made some time after these, 
gave rise to much more pronounced results. To determine the degree 
of homogeneity of the wire I compared parts of it of about 100 cm each, 
the original positions of which were about equidistant 'along the whole 
130 meters of platinum wire. The galvanics and thermo-electrics of these 
samples ranged as follows, each having been softened before testing: 
Table 37 
— Electrical tests for purity. 
Galvanics. 
No. 
Tbermo-electrics. 
No. 
rt 
t 
q x lOe 
St 
t 
T 
e 
B 
1115 
23 
1493 
16.7 
— B+0 
25 
358 
-127 
O 
1220 
23 
1493 
18.2 
-(7+0 
25 
358 
—358 
D 
1198 
23 
1493 
17.9 
— 2>+0 
25 
358 
-386 
E 
1185 
23 
1493 
17.7 
-E+0 
25 
358 
-284 
F 
1058 
23 
1493 
15.8 
+ F—0 
25 
358 
+18 
-O+A 
25 
358 
-691 
(801) 
