30 Changes of Voltaic Energy of Alloys during Fusion. 



time in a vertical position. Each of these amalgams gave 

 only a small amount of sudden increase of current at the 

 period of liquefaction, probably because the liquefaction was 

 more gradual, and the effects of solution in mercury of the 

 other metals present masked those of fusion. 



Experiment 7. An amalgam of 1 part cadmium and 4 parts 

 of mercury, in the weak solution of common salt. The 

 amalgam was more solid at 16° C. than the other three, but it 

 easily liquefied in boiling water. When it was heated and 

 had become pasty, the current began to increase ; but just 

 previous to complete liquefaction the current suddenly and 

 considerably decreased, and the liquid amalgam became electro- 

 negative to the solid one ; the period of reversal was very 

 brief, and on further heating the current suddenly increased 

 to a slightly higher point than it was at previously. The 

 annexed curve approximately represents the results obtained 

 with a freshly prepared portion of the amalgam, and shows 

 that the phenomenon is much more complex than a simple 

 measurement of the total amount of heat evolved or absorbed 

 would indicate. The sudden depression of electric energy 

 was probably due to a sudden act of chemical union of the 

 ingredients and a corresponding loss of potential (i. e. latent 

 or specific) heat. 



Curve of Variation of Electromotive Force of Cadmium Amalgam pro- 

 duced by heating and fusion in a 1-per-cent. Solution of Sodium 

 Chloride. 



Deflexions. 



70 80 90 100 110 120 130 140 150 160 170 180 Fahrenheit. 



Above the hot electrode was +, below it was negative to the cold one. 



By repeated experiments of the above kind with this 

 amalgam it was found that the sudden decrease of electric 

 current was greater with the freshly prepared substance than 

 with that which had been remelted several times, and 1 



