Effects in Tellurium. 63 



the Ettingshausen effect would require a primary electric cur- 

 rent in the direction opposite to the heat flow producing the 

 Leduc effect. These facts are of especial interest in connection 

 with Liebenow's* theory of thermo-electric currents, in which 

 he arrives at the conclusion that in metals heat always flows 

 with the negative electricity, whereas in non-metals it accom- 

 panies the positive electricity. If this relation between the 

 directions be a general one, a knowledge of the direction of 

 any one of the four transversal effects would be sufficient to 

 determine the direction of the other three. Of the eleven 

 elements examined by Nernstf for the Nernst effect, six (Bi, 

 Sb, Ni, Fe, Zn, Pb) bear out this relation with the Hall effect, 

 if we regard antimony as a non-metal. Of the other five, 

 three (Cu, Ag, Sn) showed such a small effect that they may 

 be regarded as doubtful. The two notable exceptions are cai% 

 bon and cobalt. It has been already noted by several writers^: 

 that cobalt occupies an anomalous position as regards its Hall- 

 constant, and it may be that the Ettingshausen effect is large 

 enough in this metal to entirely vitiate the measurements 

 .which have been made of its Hall-effect, even to changing the 

 sign. In this regard it is to be noted that the thermo-electric- 

 power is large between cobalt and copper, the metal usually 

 used for lead-wires. Or the measurement of Nernst effect may 

 have been equally influenced by Leduc effect. Moreau (I. e.) 

 however, found an opposite direction for the Nernst effect in 

 cobalt, which would make it agree with the general rule. The 

 direction of the Ettingshausen effect in antimony is in har- 

 mony with the other effects. 



This idea comes in conflict, however, with the " Electronen- 

 theorie" of Drude,§ which requires that the Ettingshausen 

 effect be in the same direction in all metals. For the above 

 relation to hold, the Hall-effect must also be in the same direc- 

 tion in all metals, which we know is not the fact. In the only 

 three substances yet examined, bismuth, tellurium and anti- 

 mony, the direction of the Ettingshausen effect has been found 

 the same. 



I summarize the constants for the four transversal effects. 



-ti-max * 



Ettingshausen P = 0*0002 5500 65- 



Nernst Q = 0-36 3000 33* 



Hall... __. R^430- 4000 65- 



Leduc _. S = 0-000004 5200 30-38 



* Wied Ann., lxviii, p. 316, 1899. f Wied. Ana., xxxi, p. 760, 1887. 



fYon Ettingshausen u. Nernst, Wiener Berichte, xciv, p. 560, 1886; J. C, 

 Beattie, Proc. Royal Soc. Edinburgh, xx, p. 481, 1895; Drude, Ann. d. Phys., iii, 

 p. 392, 1900. § Ann. d. Physik, iii, p. 369, 1900. 



Laboratory of Physics, 



University of Pennsylvania, 



June 1, 1901. 



