Force  in  the  Contact  of  Metals. 
271 
Copper-Bismuth . 
Exp.  62.                            No.  1. 
Diff.  of  temp.            Deviations.                Conducting-power 
8°3     .     .     .     297-0 
64-5 
8-1     .     .     .     288-8 
64-0 
7-9     .     .     .     282-5 
64-5 
7-7     .     .     .     276-0 
64-5 
Mean  .  8-0      Mean  .  286-08           Mean 
,  64-4 
Exp.  63.                             No.  1. 
7-9     ..     .     285-0 
64-5 
79     ..     .     2750 
63-0 
7'7     .     .     .     268-0 
65-0 
7-5     ..     .     258-7            Mean 
•  64-2 
Mean  .  7'75     Mean  .  271*7 
Exp.  64                            No.  2. 
91     .     .     .     290-0 
64-5 
8-8     ..     .     286-0 
65-5 
8-7     ..     .     282-0 
64-5 
8-4     ..     .     2760 
66-5 
Mean  .  8-75     Mean  .  283-5            Mean 
.  65-3 
Exp.  65.                             No.  2. 
6-8     .     .     .     216-3 
65-3 
6-6     ..     .     217-0 
6-8     ..     .     215-0 
6-8     ..     .     216-0 
Mean  .  6-75    Mean  .  216*08 
Whence  we  obtain  : — 
No.  1.  Deviation  =888-4~l  881.05 
»               »           =87d-7J 
No.*.      ..      =Sa-o}789,5 
Mean 
835-10 
The  great  thermoelectric  difference  between  the  two  bismuth- 
copper  combinations  is  remarkable.  Doubtless  the  cause  of  it 
is  the  crystalline  constitution  of  bismuth.  It  is  known  that  the 
thermoelectric  force  of  bismuth  and  of  antimony  varies  with  the 
plane  of  crystallization  :  the  crystals  which  at  the  point  of  junc- 
tion are  in  contact  with  the  copper  may  have  different  positions 
in  the  two  combinations. 
