200 E. von Aubel on the Influence of Magnetism 



cation has not taken place when bismuth is combined with 

 10 per cent, of lead. 



For this reason we have examined also the alloys of 

 bismuth and lead, which have furnished us with very inte- 

 resting results*, recorded in Table (d), but which do not in 

 any way explain the diminution of resistance when the tem- 

 perature rises. 



Some influence might still be attributed to the capillary 

 glass tube in which the wire of bismuth is placed. On 

 heating, the glass and bismuth expand differently, and 

 mutually impede each other in their movements. We have 

 therefore successively studied a rod of bismuth cast in a 

 capillary tube, and the same rod after having broken the 

 glass (with precautions) in such a way as not to alter the 

 metallic wire ; no change was observed in the direction of 

 these phenomena. Besides, the rods of tempered bismuth 

 were not prepared in glass tubes, and yet some of these 

 present the same peculiarity. 



We likewise assured ourselves that there was no relation 

 between the abnormal electrical phenomenon and the points 

 of fusion or specific gravities of the different kinds of 

 bismuth f. 



2. Influence of Magnetism. — On the whole the influence of 

 magnetism on the resistance of bismuth has been more feeble 

 than that which has been announced by M. Righi+. Mag- 

 netism always produces an increase of resistance ; its influence 

 diminishes when the temperature rises, and is more feeble in 

 the alloys than in the bismuth itself. 



3. Study of Compressed Bismuth. — The resistance of com- 

 pressed bismuth hardly varies with the temperature ; from 

 16°*8 to 42 0, 4 there was a slight diminution ; then an increase 

 up to 76°, also very small. 



After these first experiments, we took away the two ends of 

 the threads of compressed bismuth, on which was the fusible 

 alloy. With the rest we prepared a rod of bismuth slowly 

 cooled by the method indicated above. 



Measurements of the electrical resistances of this bismuth, 

 in this state, gave a fairly large increase of resistance when 

 the temperature rose. 



* M. Leduc bad already studied the conductility of the alloys of lead 

 and bismuth {Journal cle Physique [2], v. p. 11G), but from another point 

 of yiew. 



t Mr. C. L. Weber has made known, in 1886 (Amialcu (Jo- Physik 

 xxvii. p. 145), some very curious results on the influence of temperature 

 on the electrical conductility of the alloys of Rose, Wood, and Lipowits ; 

 but this work has no immediate connexion with our study. 



X Mr. Goldhammer (/. c.) has also found the influence of magnetism 

 more feeble than that indicated by M. Righi. 





