Force  in  the  Contact  of  Metals.  219 
The  calculation  of  these  two  experiments  gives /3y  =  0,  and  that 
of  the  observations  with  intensity  of  current 
=  tan  33°   .     .     .     «,= 10-93 
„    43°  15'  .     .     «,  =  10-22 
The  point  of  soldering  underwent  a  cooling  when  the  positive 
current  passed  from  gold  to  copper. 
Cadmium-  Copper. 
Exp.26.  Intensity  =  tan39°50'.  Exp.27.  Intensity  =  tan 39° 50'. 
Deviations. 
Deviations. 
6-00 
4-10 
505 
4-38 
&]o 
4-15 
Mean  .  .  5  73 
Mean 
.  .  421 
Ixp.  28.  Intensity  = 
tan  24°. 
Deviations. 
2-48 
1-70 
2-23 
1-60 
210 
2-40 
1-95 
Mean 
.     .     2 
•07  * 
In  experiments  27  and  28  the  interval  between  the  observa- 
tions was  15  minutes.  The  calculation  of  /3{  and  at  from  these 
two  experiments  gives  /3  =  0;  and,  from 
Exp.  27.     .     .     .     a,=5-05 
„     28.     .     .     .     a,=4^5 
Mean     .     .       4-85 
From  experiment  26,  in  which  ft  should  be  =0,  we  obtain 
«=6-87. 
The  passage  of  the  positive  current  from  copper  to  cadmium 
produced  a  cooling  at  the  point  of  contact. 
Copper-Lead. 
Exp.  29.  Intensity  =  tan  36°. 
Deviations. 
14-88 
14-45 
Mean  .  .  14-67 
Exp.  30.  Intensity  =  tan  20c 
Deviations. 
7*53 
7-57 
Mean  .  .  7*55 
