12 
DE, A. MATTHIESSEN AND M. VON BOSE ON THE INELTJENCE OF 
Here we find no permanent change in conducting power with wire 1, after being 
kept at 100° for several days, and only a very slight increase with Mdres 2 and 3. The 
formulee for the hard-di’awn and annealed wh-es agree so closely that they may also, as 
with silver and copper, be considered the same. 
In the paper just alluded to, the conducting power of pure gold was found — 
0 
Eecluced to 0°. 
1. 
72-68 at 19-3 
77-966 
2. 
73-08 at 23-3 
79-524 
3. 
73-27 at 13-8 
77-053 
4. 
73-99 at 15-1 
78-178 
The difference between hard-drawn and 
annealed wires was — 
Eeduced to 0' 
5. 
Hard dra^Aui 

74-20 at 14-8 
78-313 
Annealed . 
75-53 at 15-2 
79-833 
6. 
Hard drawn 
• • • • • 
73-78 at 15-5 
78-067 
Annealed . 
75-18 at 15-8 
79-635 
Taking the mean of the values as with copper, the following formulae were deduced 
for the correction of conducting power for temperature : — 
For hard-drawn wires A=77’964— 0-28648#-{-0‘0006582^^ 
For annealed wires X=79-327— 0*29149^-|-0-0006697^^ 
Zinc. 
Zinc firee of arsenic was purified by distillation. All pressed wires. In Table V. the 
results obtained are given. 
Table V. 
First wire. 
Second wire. 
Third wire. 
Length 
502*2 millims. 
394 millims. 
37 ^ millims. 
Diameter 
0*588 millim. 
0*513 millim. 
0*519 millim. 
Conducting power 
found before heat- 
0 Reduced to 0°. 
Q Reduced to 0°. 
Reduced to 0°. 
ing the wires 
26*744 at 23*1 29*093 
26*903 at 18*5 28*836 
26*835 at 18*0 28*639 
Ditto, after being 
kept at 100'^ for 
26*784 at 18*5 28*636 
1 day 
26*695 at 23*7 29*103 
27-081 at 17-5 28-919 
Ditto, for 2 days... 
26*980 at 18*5 28*919 
26*885 at 17*4 28*632 
The means of the conducting powers found for each of the following temperatures 
were — 
