Thermoelectric Properties of Crystalline Bismuth. 

 i. Crystallographic Axis. 



341 



t L . 



t.,. 



e (microvolts). 



o 



-65 



o 

 — 155 



-1166 



-108 



-163 



- 1507 



-123 



-167 



-1383 



-132 



-168 



-1243 



-136 



-170 



-1166 



The discontinuity in the curve at low temperatures was 

 found by Fleming and Dewar * for both pure and commercial 

 bismuth. Their sample of pure bismuth was not obtained, 

 however, by electrolytic deposition; and I am not aware of 

 any determination of the thermoelectric force for an electro- 

 lvtically prepared specimen of bismuth. It would be of 

 importance to know this, as the discontinuity may be due to 

 impurities. 



Perrot f has already determined the thermoelectric force 

 in the same directions with relation to the axis, as in this 

 work, the range of temperature being from 10° to 100°. 

 For purpose of comparison the thermoelectric force for the 

 present crystal was determined over a similar temperature 

 range. 



The results were : — 



1. Parallel to the crystallographic axis : 



« 1 =12°'7 ; * 2 =91° ; e=9267 microvolts, 

 or 118*35 my. per 1°. 



2. Perpendicular to the crystallographic axis : 



^ = 15°-3; f 2 = 85°*9; ^ = 4377 microvolts, 



Ratio U =1-91. 



or 61*94 mv. per 1 . 



Perrot found the ratio to vary from 1*85 to 2*10 for the 

 several prisms used by him. The specimens he considered 

 the best gave the ratio 2*00. 



My best thanks are due to Prof. Warburg for suggestions 

 and encouragement during the progress of this work. 



Physical Institute, Berlin University. 



* J. A. Fleming and J. Dewar, Phil. Mag. xl. p.9o (1895). 

 t Perrot, Arch, des Scien. phys. et nat. Aug. 1898. 



Phil. Mag. S. 6. Vol. 2. No. 10. Oct. 1901. 2 A 



