22 
Mr. Harris on the relative powers of various 
2ndly. Considering silver and copper as the best conduc¬ 
tors, (being the least heated by the explosion) then the 
conducting power of 
Gold to copper or silver is as 
Zinc or brass to copper or silver 
Platinum or iron to copper or silver - 
Tin to copper or silver 
Lead to copper or silver 
2 : 3 
1 ; 3 
1 : 5 
1 : 6 
1 : 12 
srdly. It may be observed 'that the conducting power of 
metals, when alloyed, is variously affected: thus the con¬ 
ducting power of gold and copper, or gold and silver, when 
alloyed together, is less than either of these metals in a 
separate state; and the difference in the conducting power 
increases with the quantity of the inferior conductor alloyed. 
Thus, gold one part, with copper three parts, had its tempe¬ 
rature raised to 15° of the scale; gold and copper in equal 
parts to 20°; gold three parts, with copper one part, to 25°: 
the same may be said of gold and silver ; whilst an alloy of 
copper and silver, in similar proportions, does not vary from 
either of the metals separately. 
Tin and lead, alloyed, appears to give a conducting power 
formed by that of each metal taken singly, and varying, as 
above, with the quantity of the inferior conductor; thus, an 
alloy of lead and tin in equal parts, gives an effect equal to 
one-half the effect on tin, added to one-half the effect on lead, 
and so on ; the same may be said of zinc and tin. 
4thly. It is observable that a very small quantity of alloy 
may influence materially the conducting power; thus copper 
alloyed with only one-eighth part of its weight of tin, becomes 
