162 
DE. A. MATTHTESSEX OX THE ELECTEIC 
put to the alloy, and the value for its conducting power is the mean of several deter- 
minations. A greater accuracy than that which has been obtained could not be expected, 
on account of the great difficulty of pressing or drawing a wire perfectly round and of 
a homogeneous composition. Those alloys which were drawn into wire ’ndll be under- 
lined, and when the whole series was drawn, it will be mentioned in a foot note. 
Table I. 
Bismuth-Tin Series. 
Alloy. 
Conducting 
power, 
I. wire. 
Tempera- 
ture. 
Conducting 
power, 
II. wire. 
Tempera- 
ture. 
Conducting 
power, 
III. wire. 
Tempera- 
ture. 
ilean 
Conducting 
power . 
of . 
Tempera- 1 
ture. ! 

1-08 
25-0 
1-08 
25-2 
1-07 
25-3 
1-08 
25-2 : 
Sn 
0-420 
27-0 
0-414 
27-2 
0-421 
27-2 
0-418 
27-1 
Sn 
0-262 
26-2 
0-267 
26-4 
0-262 
26-4 
0-264 
26-3 
B>44 
Sn 
0-246 
26-7 
0-244 
26-9 
0-244 
26-9 
0-245 
26-8 
Ei3o 
Sn 
0-256 
23-6 
0-253 
23-8 
0-256 
24-8 
0-255 
24-1 
Sn 
0-352 
24-4 
0-357 
24-8 
0-360 
24-8 
0-356 
24-7 
Big 
Sn 
0-513 
29-6 
0-515 
29-8 
0-510 
29-7 
0-513 
29*7 
Bi, 
Sn 
0-630 
29*4 
0-629 
29-6 
0-637 
29*8 
0-632 
29-6 
B12 
Sn 
1-03 
30-0 
1-02 
29-9 
1-06 
29-9 
1-04 
29-4 
Bi 
Sn 
2-22 
28-3 
2-23 
28-5 
2-28 
28-7 
2-24 
28-5 
Bi 
Sng 
3-93 
25-6 
3-97 
25-7 
3-97 
25-8 
3-96 
25-7 
Bi 
Sn^ 
5-84 
23-0 
5-85 
24-2 
5-83 
24-4 
5-84 
23-8 
Bi 
Sng 
7-02 
27-8 
7-12 
280 
6-99 
28-0 
7-04 
27-9 
Bi 
Sng 
7-79 
24-8 
7-82 
24-8 
7-84 
25-0 
7-82 
24-9 
Bi 
Sn44 
10-22 
24-0 
10-43 
24-4 
10-57 
24-3 
10-41 
04.0 
Determinations made with pressed and drawn lead wires gave exactly the same values. 
The following alloys, viz. the two last silver-lead, the two last silver-tin, the two last 
gold-tin, and all the gold- and silver-copper alloys, were made in the manner which will 
be described in a paper “On the Conducting Powers of Copper,” &c., by Dr. M. Holz- 
MAJSTN and myself. 
The alloys used for the determinations were those whose specific gravities have been 
determined*; and the metals composing them may be classed under two heads, viz. — 
Class A. Those metals which, when alloyed with one another, conduct electricity in 
the ratio of their relative volumes. 
Class B. Those metals which, when alloyed with one of the metals belonging to 
Class A, or with one another, do not conduct electricity in the ratio of their relative 
volumes, but always in a lower degree than the mean of their volumes. 
To Class A. belong lead, tin, zinc, and cadmium. 
To Class B. belong bismuth, mercury, antimony, platinum, palladium, iron, alumi- 
nium, gold, copper, silver, and in all probability most of the other metals. 
I shall now say a few words — 
1. On the conducting power of the metals employed. 
2. On the conducting power of the alloys made of the metals of Class A. with one 
another. 
* On the Specific Gravity of Alloys iu this volume, p. 177. 
