COISDUCTING-  POWEE  OF  THE  METALS. 
385 
Conducting 
power. 
Alloy  of  Antimony  2 parts  rO-412 
Zinc  1 part  . .l0’414 
Graphite,  No.  1 . . 
r0-( 
lo-( 
Graphite,  No.  2 . 
'0-0719 
•0667 
'0-0436 
0-0436 
'0-0372 
Gas-coke ■^0-0405 
[0-0383 
rO-00370 
•00420 
rO-00217 
0-00289 
0-00233 
Graphite,  No.  3 . 
Bunsex’s  battery-coke 
Temperature. 
Mean  of 
conducting  power. 
at 
25-01 
at 
25-0  j 
at 
22-0'! 
at 
22-OJ 
at 
22-0'! 
at 
22-OJ 
at 
25-0'! 
at 
25-oi 
at 
25-oJ 
at 
22-0-1 
at 
22-OJ 
at 
26-2'! 
at 
26-2  i 
at 
26-2J 
0-413 
0-0693 
0-0436 
0-0386 
0-00395 
0-00246 
Tellurium 
Red  phosphorus 
0-000742  at  20-0'| 
0-000795  at  20-0 1 
0-000794  at  18-7J 
0-00000118  at  20-0'! 
0-00000128  at  20-0J 
0-000777 
0-00000123 
Temperature. 
oC. 
25-0 
22-0 
22-0 
25- 0 
22-0 
26- 2 
19- 6 
20- 0 
For  the  determination  of  the  conducting  powers  of  these  bodies,  whose  electric  resist- 
ance was  very  great,  a number  of  normal  wires  of  ditferent  lengths  were  made,  and  by 
these  means  accurate  results  were  obtained. 
The  conducting  powers  of  potassium  and  sodium*  are  here  given  to  make  the  series 
complete.  The  alloys  of  bismuth-tin,  bismuth-antimony,  and  antimony-zinc  were  deter- 
mined in  order  to  ascertain  whether,  as  they  give  with  other  metals  such  strong  thermo- 
electric currents,  they  might  be  more  advantageously  employed  for  thermo-electric 
batteries  than  those  constructed  of  bismuth  and  antimony. 
All  the  metals  were  the  same  as  those  used  for  my  thermo-electric  experiments,  with 
the  exception  of  cadmium,  which  was  purified  by  my  friend  Mr.  B.  Jegel.  Coppers 
Nos.  1,  2 and  3,  were  wires  of  commerce.  In  No.  1 small  quantities  of  lead,  tin,  zinc, 
and  nickel  were  found  by  Mr.  Heeschel,  who  was  kind  enough  to  analyse  it.  The 
small  conducting  powers  of  this  sort  may  be  attributed,  according  to  the  opinion  of  Pro- 
fessor Buxsex,  to  a trace  of  suboxide  of  copper  probably  contained  in  the  same. 
The  values  obtained  for  aluminium  are  nearly  the  same  as  those  found  by  Poggen- 
DOEFFf  and  BuffJ. 
Iron,  Nos.  1,  2 and  3,  were  pianoforte  wires.  These  determinations,  although  higher 
* Phil.  Mag.  Feb:  1857.  J Pogg.  Ann.  vol.  xcix.  p.  643. 
3 F 2 
t Ann.  Chim.  Pharm.  vol.  cii.  p 265. 
