128 

 TABLE II. 



All the above wires were hard-drawn. On looking at the above, 

 we find that pure copper conducts better than any of the alloys. 



With regard to the analyses, the quantity of each specimen was 

 so small that they could not be checked by repetition; they, how- 

 ever, approach very closely to the composition assigned to them by 

 Messrs. Johnson and Matthey (with the exception of the suboxide). 

 The traces of iron will be due to the draw-plates. I will now make 

 a few remarks on the above results. 



I. That copper containing 0'25 per cent, of silver conducts better 

 than that with 0' 13 per cent., may be explained by assuming that the 

 first contains less suboxide than the second ; for it is very possible 

 that copper containing silver will not absorb suboxide so readily as 

 the purer metal. It must also be borne in mind that the copper em- 

 ployed for making these alloys was in all probability simply electro- 

 type copper (not fused), and that the suboxide therefore was ab- 

 sorbed during the process of fusing the two metals together. This 

 assumption explains how it is that the alloys contain almost the same 

 amount of impurity as was originally alloyed with the copper ; for 

 had the copper employed contained suboxide, we should have ex- 

 pected to have found greater differences in the cases of the tin, lead, 

 and zinc alloys, as some portion of those metals would have been ox- 

 idized at the expense of part of the suboxide of copper, and escaped 

 as oxide to the surface of the melted metal. 



