242 



vations of Richardson, or on the conlrarj whether it will be able 

 to clear up the difliculties which still present themselves in the 

 discussion of the RiCHARDsoN-efifect. 



§ 3. The thermoelectric power. To calculate the thermoelectric 

 power (for 1 degree temperature difference between the two joints) 



in a circuit of two metals A and B, 

 we assume ^) 1 coulomb of free elec- 

 trons to be driven round in the direc- 

 tion of the arrows in the figure, cal- 



^ culate the external work which in 



*^ that pi-ocess lias to be jier formed on 



ihe electrons as on an ideal gas, divide by clT and multiplj by 

 — 1. We then obtain: 





"5 



F = 10-8 



■ƒ©;'• 



(1) 



Here F is the thermoelectric power in Volts and v represents the 

 volume of 1 coulomb of electrons. 



With the aid of equation (1), which can also be written in the 



form i^=10-8. 





(i|) being the free energ}"), from the 



values of U and aS of § 3 of the former paper a general formula 

 for F can be derived. We shall only give the limiting laws for the 

 high and for the low temperatures. 



For the high temperatures, viz. such at which equipartition 

 prevails, from equation (J 4) of the former paper the well known 

 formula 



F= 10-« 



k - Vb 

 — In — - 



e Va 



(2) 



follows, if e = the charge in coulombs of 'J electron. 



For low temperatures equation (20) of the former paper leads lo ^) : 



1) Gf. K. Baedeker, 1. c. Gf. . also F. Krüger, Physik. Zeitsch. 11 (1910), 

 p. 800, 12 (1911), p. 360. 



~) We remark that for these low temperatures the following simple relation 

 exists between the tliermoeleclric power and the specific heat of the electrons 



Ae 6 



