BABus.] PYRO-ELECTRIC PROPERTIES OF ALLOYS. 135 
Table 31.— Electrical resistance of platinum alloys (thin wires)— Continued. 
No. 
Alloy. 
n 
t 
tfXIO 6 
St' 
18 
Nickel 
21180 
18510 
25560 
19950 
26400 
14720 
23130 
26620 
37710 
37510 
17690 
34870 
28770 
17600 
26030 
32670 
22 
22 
22 
22 
23 
23 
22 
23 
23 
23 
23 
23 
23 
23 
23 
23 
1576 
1576 
1576 
1590 
1713 
1676 
1590 
1590 
1598 
1676 
1662 
1735 
1735 
1590 
1590 
1619 
33.38 
29.17 
40.29 
31.72 
45.24 
24.68 
36.78 
42.33 
60.28 
62.88 
29 39 
19 
Cobalt 
20 
...do 
21 
....do 
40 
...do 
41 
....do 
2" 
Iron 
23 
...do 
24 
...do 
42 
....do 
43 
...do 
50 
...do 
60 51 
51 
...do 
49 91 
25 
Chromium 
27 99 
2fi 
...do 
41 39 
27 
....do.. •:... 
52 90 
44 
...do 
28 
Tin 
13720 
16090 
24280 
15700 
13220 
15900 
29900 
9700 
11840 
23 
22 
22 
22 
22 
22 
22 
22 
16r9 
1633 
1662 
1655 
1655 
1655 
1647 
1720 
1662 
2° 21 
29 
...do 
26 27 
30 
...do 
40 35 
31 
25 98 
32 
....do 
21.88 
33 
26.31 
34 
....do 
49.25 
35 
16.68 
3fi 
...do 
19.67 
45 
....do 
37 
Lead 
8940 
10510 
17830 
22 
23 
23 
1720 
1691 
1691 
15.37 
46 
17.76 
38 
Antimony „ 
30.14 
39 
Bismuth , 
47 
....do 
9890 
26340 
14890 
23 
23 
23 
1676 
1691 
1691 
16.57 
52 
44.55 
54 
....do 
25.17 
53 
A 
C 
) Platinum purified by three fusions (lhalf an hour of melt- 
<; 710 
* 504 
23 
23 
1810 
2781 
12.86 
14.02 
Thermo-electrics of wires. — Having obtained this table in the way- 
described, the marked ends of the wires were next subjected to thermo- 
electric measurement by exposing them to temperatures 100°, 358°, and 
448°, respectively, in the boiling tubes, already fully described in Chap- 
ter II. The results are given m Table 32. "No." refers to the individ- 
ual wires of the couple examined, and gives the sign of the two metals 
thermo-electrically combined. Thus Au(-fl— 0) denotes that the gold- 
alloy No. 1 is thermo-electrically positive to platinum No. 0. T and t 
are the temperatures of the thermo-electric junctions for which the 
electro-motive forces e (microvolts) apply, a and b the corresponding 
thermo-electric constants. Inasmuch as the thermo-electric data are 
necessarily most seriously affected by impurities in the alloys, it 
(780) 
