Voltaic Energy of Alloys during Fusion. 29 



Three electrolytes were used, viz. one composed of 1 part 

 by weight of absolute hydrochloric acid in 100 of water ; a 

 second, of 1 part of chloride of sodium and 100 of water ; 

 and a nearly saturated solution of that salt. 



In the following experiments : 1st, on applying heat, the 

 heated portion of the alloy became gradually electropositive 

 to the cold portion up to its fusion-point ; and, 2nd, a more or 

 less sudden increase of electromotive force occurred during 

 the further heating of the alloy and the electrolyte up to the 

 boiling-point of the latter, and this sudden increase appeared 

 to coincide in point of time with the melting of the alloy, but 

 this could not be accurately determined, especially with the 

 amalgams in experiments No. 4, 5, and 6, because the fusion- 

 point was not sufficiently sudden or distinct. Substantially 

 the reverse of these phenomena happened after removing the 

 flame, during the processes of evolving latent heat and subse- 

 quent cooling. A partial exception to the phenomenon of 

 sudden increase of electromotive force during the act of 

 fusion took place with cadmium amalgam in experiment No. 7. 



Experiment 1. Fusible alloy of bismuth 70 parts, lead 40, 

 tin 20, and cadmium 15. Melting at about 66° C. In the dilute 

 acid at 16° G. The amount of sudden effect by gradual 

 heating in this case was quite large, and the galvanometer 

 deflexion increased from 20° to 60°. Experiment 2. The 

 same alloy in the weak solution of sodium chloride at about 

 16° C. The amount of sudden increase of current by gradual 

 heating was again large. Experiment 3. An alloy of bismuth 

 8 parts, lead 8 parts, and tin 3. Melting at about 107° C. 

 In the concentrated solution of sodium chloride. The sudden 

 increase of current by gradual heating was considerable. 



As in each of these instances there was a more or less sudden 

 change of physical state of the alloy, but no such change of the 

 electrolyte, the coincident rapid increase of electromotive force 

 must have been due to the alloy and not to the electrolyte ; 

 it could not have been due to a sudden rise of temperature, 

 because that of both substances must have remained nearly 

 stationary during the act of fusion in consequence of the heat 

 becoming latent. 



The next three experiments were made with mercurial 

 amalgams. Experiment 4. An amalgam of bismuth 10 parts, 

 tin 3*5, lead 3' 2, and mercury 2*0, in the weak solution of 

 common salt. Experiment 5. Amalgam of zinc 1 part, and 

 mercury 7, in the same liquid. Experiment 6. Amalgam of 

 tin corresponding in composition to the formula Sn^Hgs, in 

 the same solution. This amalgam was soft at 16° C, and 

 mercury drained out of it after standing a bar of it some 



