THERMO-ELECTRIC QUALITY UNDER PRESSURE. 



375 



indicated in the figure by the arrows AB and CD, by means of which 

 a load may be applied to either wire separately or together. The 

 upper and lower ends of the wires are surrounded by two thermo- 

 stated baths, indicated by the open rectangles in the figure, which 

 may be kept at any desired two different temperatures. In use the 

 lower bath was always packed with ice, and the upper bath was set 

 at any desired temperature between 0° and 100° C. The two wires 



FiGUEE 46. Scheme of connections used in finding effect of tension oi) 

 thermo-electric quality. 



are tapped at the middle of the upper bath by two flexible leads of 

 copper connecting to the galvanometer G and the potentiometer P. 

 These instruments were the same as were used in the previous measure- 

 ments. The balances are insolated from each other, so that the 

 circuit runs from G to P to G to F to E to G. If the two wires are 

 precisely alike, there is no thermal e.m.f. in this circuit for any differ- 

 ence of temperature between GF and E, but if one of the wires is 



