444 Mr. R. S. Willows on tlw Variation of the 



There is a large increase in resistance between temperatures 

 corresponding to points M and N. The following table gives 

 the temperatures between which this large increase takes 

 place and the percentage increase in resistance for 1° for the 

 different percentages of tin. 



Table III. 



Percent, of Tin. 



Temp, at M. 



Temp, at N. 



P.c. increase for 1°. 



9-6 



76 



96 



•23 



19-3 



79 



115 



•5 



29 9 



83 



124 



•9 



In contrast with zinc amalgams, those containing tin 

 showed no difference in behaviour when they were repeatedly 

 heated ; the resistance took the same value at the same 

 temperature whether the substance was being heated or 

 cooled ; if the spiral is heated, and then allowed to stand at 

 the temperature of the room, its resistance does not alter 

 with time. 



§ 5. Cadmium Amalgams. 

 Various cadmium amalgams were tried. Fig. 8 represents 

 the resulting curve for a specimen containing 20 per cent, of 

 cadmium. It is typical of the others which were obtained. 



Fi<>\ 8. — Resistance of an Amalgam containing 20 per cent, of Cadmium. 



As in the case of tin amalgams, they show a large tem- 

 perature-coefficient at one part of the temperature-scale. 



Like zinc amalgams, the cadmium amalgams (a) possess a 

 different resistance at the same temperature according as 

 they are being heated or cooled, but in this case the resistance 



