240 EXPERIMENTAL INVESTIGATIONS. 



cleaned platinum in hydrogen gas, and then immersed it in 

 mercury ; when either platinum or mercury was moist I 

 perceived a tendency to amalgamation, but none when they 

 were perfectly dry. As I hope to renew this examination 

 with a more perfect apparatus, I will not detail any more of 

 these experiments, but merely state my impression to be that 

 mercury under the influence of a voltaic current is capable of 

 absorbing a very small quantity of hydrogen, which it gives 

 up as soon as the communication is interrupted. 



The probability of a temporary combination of hydrogen 

 with mercury throws some light upon the movements of mer- 

 cury submitted, under an electrolyte, to a voltaic current : the 

 hydruretted particles of mercury are repelled until out of the 

 immediate influence of the current, where they yield their 

 hydrogen, and so on of the rest. In electrolysation with a 

 mass of mercury as negative electrode, the hydrogen is all 

 evolved at the parts most distant from the positive electrode. 



In order to see whether this property of complete polari- 

 sation was proper to mercury, or common to all metals in a 

 state of fusion, I caused two currents, one proceeding from a 

 voltaic pair consisting of zinc and a fused globule of Darcet's 

 alloy, the other from zinc and mercury kept at the same tem- 

 perature, to pass in contrary directions through the wire of a 

 galvanometer ; the current proceeding from the first pair was 

 much more energetic than that from the second, and kept the 

 needle constantly at 85 degrees. I could not repeat the ex- 

 periment with other metals, from the impossibility of keeping 

 them fused without volatilising the electrolyte. As far as 

 this case goes, it would seem that metals possess different 

 polarising capacities. I have before remarked a difference in 

 the proportionate diminution of the current by polarisation 

 with solid metals, and think the subject merits an experimental 

 examination. 



