1115 



and with earlier experiments of von Bose and Matthiesrn \) wlio 

 found for the conductivity between 10° and 100° : 



k = 4,6172—0,018389 & + 0,00004785 0' 



^ 3. Orientation curve. 



Tliis was determined at 18° and about 23 K.G. The resistance of 

 the crystal was measured with the axis normal and parellel to the 



') V. Bose und Mathiessen, Pogg. Ann. 115, p. 353, 1862. 



