346 



Dr. E. van Aubel's Researches 



on 





Alloys 



with Lead. 









w. 



K. 





Alloys. 



Tempera- 



Electrical 



Variation for 



E . 



tures. 



resistances 



1° between 0° 







in U.S. 



and 100°. 





1st. Rods slowly cooled. 





Latest Brommsdorff 



Bi + Pb. 



0-5 gr. Pb to 100 gr. Bi. 



o 



f ° 



J 19-1 

 1 69-0 

 [99-6 



( ° 



0-2125 

 0-2122 

 0-2L27 

 0-2200 

 0-4037 







Bi Classen I. + Pb. 



19 



0-3887 





10 3 x 362-32 



0-5 Pb to 100 gr. Bi. 



49-1 

 L99-6 



3690 

 0-3530 







2nd. Tempered Rods. 





Latest Brommsdorff 



Bi + Pb. 



0-5 gr. Pb to 100 gr. Bi. 



( ° 

 j 17-6 



0-1420 

 0-1425 







149-2 

 [99-7 



01400 

 01365 





10 3 x 245-70 





1 ° 



01475 







Bi Classen 1. 4- Pb. 



17-5 



01485 







0-5 gr. Pbto 100 gr. Bi. 



49-1 

 [99-7 



0-1470 





10 3 x 274-27 





01414 







Conclusions. 



I have observed that the electrical resistances of some rods 

 were changed permanently after the first heating ; but when 

 once the values remain constant they do not change again, 

 even after several months. Dr. Leduc* has observed a 

 similar phenomenon. Rods of the same bismuths, either 

 slowly cooled or hardened under the same conditions, give 

 nearly the same values for the resistance at 0° and for the 

 coefficient of variation with the temperature. The methods 

 of tempering and of slowly cooling remain sensibly the same 

 for the different specimens. We must not then look to this 

 cause to explain the great variations which have been ob- 

 served between one bismuth and another. 



The molecular structure, which I have changed by temper- 

 in a- and by compression, makes a great difference in the 

 electrical properties of impure bismuths. On the other hand, 

 tempering appears to have no action whatever on pure bis- 

 muth ; thus, the electrical resistance at 0° is : — 



* Thesis for doctor's degree, p. 30, 



