M2 



had iilready been used by Dr. B. Hkckman foi- ineasnretnents con- 

 cerning the influence of the magnetic field on the resistance. 



The resistance approaches here to a definite limiting value, in the 

 same Avay as this has already been found for other not quite pure 

 metals (Conmi. N". 119). 



d. Constant/n and mangnnin. The temperature coefficient of con- 

 stantin which is extremely small even down to oxygen temperatures, 

 increases considerably in the region of the Indrogen temperatures, 

 so that constantin wires are suitable thermometers in this region 

 and especially in the region of helium temperatures. 



Tcaic are the values calculated by means of a linear formula of 

 the form 



t = a-^hw 



through the j^oints at 20^^36 and 1.5°. 83. The deviation does not 

 amount to more than 0°.04 and shows thus the suitability of con- 

 stantin wires as thermometers in the hydrogen region, wiiere the 

 platinum-thermometer would require complicated calibrations (comp. 

 Coram. W. 142c). 



