372 
DE.  A.  MATTHIESSEN  ON  THE  THEEMO-ELECTEIC  SEEIES. 
with  ashes.  The  one  box  was  filled  with  warm  water,  and  the  other  with  water  ha^■ing 
the  temperature  of  the  room;  the  wires  were  introduced  partly  through  holes  in  the 
covers  and  partly  through  holes  in  the  sides,  which  were  made  water-tight  with  india- 
rubber  tubing.  In  order  to  prevent  any  conducting  of  the  electric  current  through  the 
water,  the  wires  were  covered  with  thin  india-rubber  tubes,  and  by  means  of  stirrers  a 
uniformity  of  temperature  was  kept  up  throughout  each  of  the  boxes.  In  consequence 
of  their  size  and  their  double  sides,  the  temperature  hardly  varied  duiing  the  time  an 
observation  was  being  made.  If  the  electromotive  powers  of  a thermo-element  were  in 
exact  ratio  with  the  diflerence  of  the  temperatures,  the  knowledge  of  the  same  would 
not  be  necessary  with  the  arrangement  described ; but  as  this  is  not  exactly  the  case,  the 
temperatures  were  observed  by  means  of  thermometers  placed  in  the  boxes  through  the 
covers.  Table  II.,  the  arrangement  of  which  will  be  explained  immediately,  con  tains 
the  results  of  the  observations  made  in  the  manner  above  described. 
Table  II. 
Silver,  Bismuth  (commercial  wires) — 5 Silver,  Copper. 
O o Mean. 
ri  = 7-6  ^2=24-0  ?;=7T63'| 
ri  = 7-6  4=23-0  ?;=7-I64l7-162 
4 = 7-6  4=22-4  ^=7-159) 
Silver,  Bismuth  (pure  vrires) — 5 Silver,  Copper. 
4 = 4-2  4=23-7  t>=6-585'| 
4 = 4-2  4=22-6  ^=6-586 16-582 
4 = 4-2  4=21-8  ^;=6-575j 
Silver,  Potassium — 2 Silver,  Copper. 
4 = 4-0  4=29-3  ^;=2-748'j 
4 = 4-0  4=27-3  ?;=2-749 12-746 
4 = 4-0  4=25-9  ^^=2-742) 
Silver,  Argentine — 2 Silver,  Copper. 
4 = 5-6  4=32-1  i'=2-620^ 
4=5-6  4=31-0  v=2-62ll2-620 
4 = 5-6  4=30-0  ?;=2-620j 
Silver,  Palladium — 2 Silver,  Copper. 
4 = 4-4  4=27-7  i;=l-783'l 
4 = 4-4  4=27-2  ^J=l-775ll-780 
4 = 4-4  4=26-0  ^=1-782) 
Silver,  Sodium — 2 Silver,  Copper. 
ll 
do 
4=28-9 
t;=l-549- 
4 = 4-8 
4=27-0 
^;  = l-546 
II 
GO 
4=26-1 
'^=1-550 
4 = 4-8 
4=26-0 
y=  1-544, 
1-547 
