THERMO ELECTRICITY. 279 



in the same direction : that when two opposing 

 metals were united in producing a thermo current, 

 the minor current would be found to neutralize 

 the opposing current, precisely to the amount of 

 its own powers, and with as much exactitude as 

 if it had been done by arithmetical calculation. 



Thus iron alone gave 7^° current. Conjoined 

 with Zinc 5' ; Zinc alone 2^° in the opposite 

 direction. 



It was also discovered that a minor current 

 conjoined to one of a more powerful nature, does 

 not generally augment, but rather diminish the 

 amount of the latter.* 



I found that the uncrystalline metals, gold, 

 silver, copper, lead, &c. were unable to develope 

 currents of any appreciable amount, (as seen also 

 in the Table,) although the heating process was 

 continued to a considerable degree of intensity, 

 (see 37, 38.) 



* It was found that the crystalline metals, Bismuth and 

 Antimony, which form the best combination for thermo- 

 electric purposes, are naturally mutually reciprocal metals. 

 Bismuth negative, 45° ; Antimony positive, current 22i° : 

 and yet, conjoined, they only produced a current of 48°. 



