TEMPEEATUEE ON THE ELECTEIC CONDUCTINO-POWEE OE ALLOYS. 181 
Table XIII. 
Alloy. 
Volumes 
per cent. 
Conducting-power at 100°. 
Percentage decrement. 
Observed. 
Calculated. 
Observed. 
Calculated. 
Gold-copper (hard drawn) 
Gold-copper (hard drawn) 
Gold-silver (hard drawn) 
Gold-silver (annealed) 
Gold-silver (hard drawn) 
Gold-silver (annealed) 
Gold-silver (hard drawn) 
Gold-silver (annealed) 
Gold-copper (hard drawn) 
Gold-copper (hard drawn) 
Platinum-silver (hard drawn) . . 
Platinum-silver (hard drawn) 
Platinum-silver (hard drawn) 
Platinum-silver (hard drawn) 
Copper- silver (hard drawn) 
Copper-silver (hard drawn) 
Copper-silver (hard drawn) 
Copper-silver (hard drawn) 
Copper-silver (hard drawn) 
Copper-silver (hard drawn) 
Iron-gold (hard drawn) 
Iron-gold (hard drawn) 
Iron-gold (hard drawn) 
Iron-copper (hard drawn) 
98-63 of Au 
81-66 of Au 
79-86 of Au 
79-86 of Au 
52-08 of Au 
52-08 of Au 
19-86 of Au 
19-86 of Au 
19-17 of Au 
0- 71 of Au 
19-65 of Pt 
5-05 of Pt 
2-51 of Pt 
23-28 of Pd 
98-35 of Cu 
95-17 of Cu 
77-64 of Cu 
46-67 of Cu 
8-25 of Cu 
1- 53 of Cu 
27-93 of Fe 
21-18 of Fe 
10-96 ofFe 
0-46 of Fe 
43-85 
14-89 
19-18 
19-38 
14-05 
1407 
19-88 
19-91 
18-86 
62-25 
6-49 
16-75 
28-07 
8-23 
65-81 
61-26 
- 52-86 
57-89 
61-69 
71-81 
1-97 
1- 64 
2- 20 
33-63 
55-33 
57- 96 
58- 25 
fa 58-25] 
[ 5 60-24 J 
62-58 
fa 62-581 
15 65-99/ 
67-60 
f a 67-60 1 
15 72-68/ 
67-68 
70-54 
59- 31 
67-77 
69- 24 
57-27 
70- 66 
70-66 
70-66 
70-68 
70-69 
70-69 
42-62 
45-64 
49-68 
70-34 
21- 87 
7- 41 
10- 09 
10-21 
6-49 
6- 71 
8- 32 
8-44 
8-07 
25- 90 
3-10 
7- 08 
11- 29 
3-40 
26- 50 
25- 57 
24-29 
22- 75 
23- 17 
26- 51 
27- 92 
17-55 
3-84 
13-44 
2222 
2- 53 
9-65 
fa 9-75 
1 5 9-43 
6- 58 
fa 6-59 
1 5 6-25 
8-62 
fa 8-63 
1 5 8-03 
8-18 
25-86 
3- 21 
7- 25 
11-88 
4- 21 
27-30 
25-41 
21-92 
24- 00 
25- 57 
29-77 
1-47 
M2 
1-34 
14-03 
These Tables will require some explanation. Calculated conducting-power means the 
deduced conducting-power of an alloy, it being assumed that the conducting-power of a 
wire of any alloy is equal to the sum of the conducting-powers of parallel wires of the 
metals composing the alloy. 
Under the term “ calculated percentage decrement between 0° and 100°,” we do not 
mean, as might be supposed, the mean of the percentage decrements which the com- 
ponent metals would suffer in their conducting-powers between 0° and 100°, and which 
would be, for nearly all the alloys experimented with, 29-307 per cent., inasmuch as it 
has been shown* that the conducting-power of most of the pure metals decreases between 
0° and 100° by 29-307 per cent, (the exceptions to this law, being thallium andiron, the 
conducting-powers of which decrease between 0° and 100° 31*420 and 38*260 per cent, 
respectively f). It is therefore clear that the calculated percentage decrement in the 
conducting-powers between 0° and 100° of most alloys, from the above assumption, must 
be also 29-307 per cent. It is, however, obvious, on looking at the observed percentage 
decrements, that the conducting-powers of the alloys, with the exception of those given 
in Table XI., decrease less than 29-307 per cent, between 0° and 100°. In order to avoid 
repetitions, instead of the above value (29-307), we have inserted under the heading 
“ calculated percentage decrement ” that deduced from the following law : — 
The observed percentage decrement in the conducting -power of an alloy between 0° and 
100° is to that calculated between 0° and 100° (viz. 29-307) as the observed conducting- 
power at 100° is to that calculated at 100°. 
* Loc. cit. 
t Philosophical Transactions for 1863. 
