on the Thermoelectrical Properties of Bismuth 287 



effects of magnetization. The numbers in this column re- 

 present the increase of resistance per unit which would be 

 produced in each of the metals by magnetizing them to 

 such an extent that each cubic centimetre would possess 

 unit magnetic moment. The effect of the magnetization in 

 this case would be nearly twice as great for cobalt as for iron, 

 twelve times as great for nickel as for iron, and, speaking- 

 very roughly, two thousand times as great for bismuth as for 

 iron. Startling as this last result is, it sinks into insignifi- 

 cance when contrasted with the results obtained by other 

 observers. The effect of magnetization on the electrical 

 resistance of bismuth is largely influenced, amongst other 

 things, by the amount of impurity in the metal and the mag- 

 nitude of the magretizing force. Thus, from Ettingshausen's 

 researches, from which Table II. has been compiled, we learn 



Ay 

 that the value of -^ for pure bismuth and for very large 



magnetizing forces* may become nearly 200 times as great as 



Table II. 

 Transverse Magnetization. 



Magnetizing force 

 in O.Gr.S. units. 



Increase of resistance 

 per unit produced 

 in pure bismuth by 



a C.G-.S. unit of 



magnetizing force, 



Ar 



rM./ 



Ditto in bismuth 

 alloyed with one 

 per cent, of tin. 



1600 

 3160 

 5880 

 8410 

 10470 

 11200 



1610x10 



2490 



3350 



3660 



3840 



3890 



660x10" 



that observed by the authorf, with the comparatively low 

 magnetizing force of 130 C.Gr.S. units ; whilst the introduc- 

 tion of one per cent, of tin diminishes the value to one sixth. 



* The bismuth was acted upon by a transverse magnetizing force, 

 which, however, has been proved to increase the resistance, though to a 

 greater extent than a longitudinally magnetizing force. 



t The specimen of bismuth used by the author has been, through the 

 kindness of Professor J. M. Thomson, analyzed at the chemical laboratory 

 at King's College, London ; it contains 98"48 per cent, of bismuth. 



