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XXVII. The Changes of Property of Amalgams by Repeated 

 Fusion. By Dr. G. Gore, F.R.S* 



IT is well known that various alloys undergo a change of 

 properties by repeated melting and cooling. Having 

 found during some experiments made for examining the 

 changes of volta-electromotive force of alloys during fusion, 

 that an amalgam composed of 1 part by weight of cadmium 

 and 4 of mercury gave different results after each successive 

 melting, notwithstanding that the chemical composition of the 

 substance remained unaltered, I took a freshly made bar of 

 the substance and a strip of sheet platinum and formed a vol- 

 taic couple with them in a solution composed of 1 part by 

 weight of common salt and 100 of distilled water, and ascer- 

 tained the fixed amounts of deflexion it produced of the 

 needles of an ordinary torsion-galvanometer of 50 ohms 

 resistance after different numbers of fusions of the amalgam ; 

 they were as follows : — 



Number of ^ a . 



Fusions. Deflexions. 



1 29 



4 24 



8 11 



12 12 



The differences of strength of current were manifestly due 

 to the fusions, and not to any loss of mercury or oxidation of 

 the cadmium. The amalgam melted at 98° C, and was not 

 on any occasion heated above 130° C. There was no visible 

 fume or sublimate caused by volatilization of the mercury, and 

 it was found in a separate experiment that a diminution of as 

 much as 20 per cent, in the proportion of mercury, produced 

 only about one degree difference of deflexion of the needles. 



I took a second freshly made bar of the same substance, and 

 measured the electromotive force of the couple in the same 

 electrolyte at 17°' 5 C. after each fusion and cooling, by the 

 method of balance, with a suitable thermoelectric pile (see 

 Proc. Birm. Phil. Soc. vol. iv. p. 130 ; < The Electrician,' 

 vol. xii. March 15, 1884, p. 414), and obtained the following 

 results : — 



Number of T7 u Number of T7 , , 



Fusions. Volts ' Fusions. Volts - 



5 . . . -7724 



1 . . . -8809 



2 . . . -8553 



3 . . . -8267 



4 . . . -7838 



Communicated by the Author. 



