380 
DE.  A.  MATTHIESSEN  OX  THE  THEE3IO-ELECTEIC  SEEIES. 
2 Silver,  Argentine — Antimony^  No.  2 (equatorial),  Silver. 
o o Mean. 
^j=23-0  4=42-0  t'  = l-314'| 
4 = 23-0  4=40-5  t-=l-315ll-31T 
4=23-2  4=32-2  ^;=l-32lj 
As  tellurium  takes  such  an  extraordinary  place  in  the  series,  it  seemed  interesting  to 
make  a few  experiments  tvith  a thermo-battery  constructed  out  of  tellmium-bismuth ; 
and  one  composed  of  eight  of  these  elements,  whose  soldering-points  had  but  60°  tem- 
perature difference,  decomposed  a solution  of  sulphate  of  copper.  A thermo-batter}', 
made  of  100  pairs  of  tellurium-bismuth,  whose  extremities  have  100°  temperatm-e 
difference,  will  give  an  electromotive  power  equal  to  four  of  Daxiell’s  cells.  Such  a 
thermo-battery  I am  at  present  constructing. 
Selenium  and  red  phosphorus  conduct  electricity,  but  so  badly,  that  the  galvanometer 
used  in  all  the  former  experiments  could  not  here  be  used,  and  in  its  stead  an  astatic 
multiplier,  with  20,000  folds  of  wires,  was  employed.  As  the  deflections  of  the  needle 
were  very  small,  in  the  calculation  the  angle  of  deflection  may  be  said  to  be  proportional 
to  the  electromotive  forces.  Table  IV.  contains  the  results  obtained  with  the  astatic- 
multiplier  and  the  copper  boxes. 
Table  IV. 
2 Silver,  Argentine — Bed  Phosphorus  (only  filed,  not  coppered).  Silver. 
- '?;=I-08 
2 Silver,  Argentine — Bed  Phosphorus  (coppered).  Silver. 
?;=I-07 
8elen,  Bismuth — 19  Copper,  Argentine. 
i;=3-57' 
^;=3-62. 
36-0 
From  the  values  of  the  thermo-electric  numbers  of  the  different  metals  given  in 
Table  I.,  the  ratio  of  the  electromotive  power  of  two  elements  constructed  out  of  any 
two  of  those  metals  may  be  calculated.  In  order,  therefore,  to  ascertain  the  accm-acy 
of  these  values,  several  combinations  were  made,  and  their  electromotive  powers  deter- 
mined. In  the  following  Tables  the  ratio  of  the  electromotive  powers  for  the  different 
combinations  is  given. 
Table  V.  Experiments  made  with  the  large  zinc  boxes  and  the  multipher. 
Eatio. 
Eound.  Calculareo. 
Silver,  Bismuth  (commercial  wu-e) — Silver,  Bismuth,  Silver,  Bismuth 
(pure  wire) 1-097  1-088 
Silver,  Potassium — Silver,  Palladium 1-543  1-542 
Silver,  Argentine — Silver,  Palladium 1-467  1-472 
