ELECTEIC CONDUCTING POWER OF PUEE COPPER AND ITS ALLOYS. 
91 
IV. Copper with 1’06 per cent, of iron 
V. Copper with 0‘48 per cent, of iron 
VI. Copper with 4'90 per cent, of tin . 
VII. Copper with 2‘52 per cent, of tin . 
VIII. Copper with 1’33 per cent, of tin . 
IX. Copper with 2-45 per cent, of silver 
X. Copper with 1-22 per cent, of silver 
XL Copper with 3-50 per cent, of gold 
27-44 at 14-2 
26-46 at 12-0 
Means. 
j26-95 at 13-1 
34-40 at ll-Oj 
34-72 at 11-4J 
34-66 at 11-2 
19-35 at 14-2 
19-60 at 14-6 
19-47 at 14-4 
32-49 at 17-01 
32-79 at 17-2J 
32-64 at 17-1 
48-76 
at 
16-8 
48-28 
at 
16-8 
80-01 
at 
19-6 
79-21 
at 
19-8 
78-93 
at 
19-8 
87-61 
at 
20-6 
86-65 
at 
20-6 
86-46 
at 
21-0 
65-10 
at 
18-0 
65-80 
at 
18-2 
66-00 
at 
18-1 
} 
48-52 at 16-8 
79-38 at 19-7 
86-91 at 20-7 
65-36 at 18-1 
We could not draw a wire of pm-e copper with only traces of lead in it, for it makes 
the copper to all appearance perfectly rotten; in Gmelin’s ‘Chemistry’ it is also stated 
that copper which contains even 0-1 per cent, of lead cannot either be drawn into fine 
wire or rolled into thin sheets. Now the copper smelters add a small quantity of lead 
to their copper, to soften and render it more tough. The addition of lead is supposed 
to reduce the suboxide of copper present ; but, according to J. Napiee’s * analysis, lead 
was always found present where it had been added, and often in quantities equal to 
the amount which had been put in. We have therefore made a few experiments in 
this direction. 
To copper fused in contact with air 0-1 per cent, of lead or tin was added, and the 
alloy fused in the tobacco-pipe in a current of carbonic acid gas. 
I. The copper employed conducted . 
II. With addition of Q-l per cent, of tin. 
III. The same repeated 
83- 44 at 13-01 
84- 45 at 13-6/ 
90-00 at 14-0| 
89-80 at 14-0 J 
Means. 
83-94 at 13-3 
89-90 at 14-0 
91-27 at 13-8-1 
90-65 at 14-OJ 
90-96 at 13-9 
IV. With addition of 0-1 per cent, of lead 
89-55 at 12-0-1 
89-42 at 13-8/ 
89-48 at 12-9 
* Philosophical Magazine, S. 4. vol. v. p. 488. 
