HALL AND C AiMPBELL, — MAGNETIC EFFECTS IN SOFT IRON. G35 



Temperature. Thermo-eloctric IumkIiI Temperature. Thornio-clectric height 



'^ (microvolts per degree)- * v.iitF>-iui.u.c. (microvolts per liegree). 



0° C. 38.04 60° C. 11.72 



10° 38.46 70° 42.71 



20° 38.94 80° 43.91 



30° 39.r)0 90° 45.33 



40° 40.14 100° 47.10 



50° 40.88 



Measurement of the Transverse Effects. 



In giving the results of our observations we shall report on the 

 various transverse effects in the order in which we have defined them. 

 Relations, theoretical or empirical, between some of them will be dis- 

 cussed later, with especial reference to the formulas of Moreau and of 

 Voigt. 



Hall Effect. — With Plate 1 we found 



B here is the temperature of the water flowing through the copper 

 blocks at the end of the plate and the iron trough in which the plate 

 lay. Cp is approximately the strength of the current through the 

 plate, expressed in absolute units ; H is approximately the strength of 

 the magnetic field at the middle part of the plate, expressed in absolute 

 units. 



The temperature-coefficient of eTe, as derived from the data here 

 given, is 



(1024 - 714) -=- 714 (53 - 12.7) = 0.0108. 



Thermo-electric action, due to the Ettingshausen transverse tempera- 

 ture-difference acting in the all-iron thermo-electric couple L-plate-I^ 

 of Figure 6, is negligible in its influence on the Hall effect as here 

 observed. 



With Plate 2, using the circuit Ci-jjlate-Ci, we found 



