84< On the Inaction of Amalgamated Zinc in acidulated Water, 



and alkaline matters *, I was anxious to discover whether 

 hydrogen alone could, by its combination in small quantities 

 with mercury, give it the same electro-positive qualities. Sir 

 Humphry Davy, aided by a costly apparatus, scarcely suc- 

 ceeded in purifying water of alkaline matters, but the affinity 

 of mercury for the alkaline metals gave me some hopes of at- 

 taining this object with less expensive means : to this end I sub- 

 mitted to electrolyzation for five days in a vessel of bees wax, 

 distilled water acidulated with pure sulphuric acid; the nega- 

 tive electrode, of amalgamated copper, terminating in a mass 

 of mercury. At the end of this period I removed the mer- 

 cury, substituting a fresh portion of the same metal which was 

 perfectly pure, and renewed the electrolyzation for two hours; 

 I then quickly inclosed this last mercury in a tube with the 

 purified water; it always evolved a small quantity of hydro- 

 gen, but I could not determine with certainty that its volume 

 bore any given proportion to that of the mercury employed. 

 Although this last portion of mercury when carefully cleaned 

 and tested with reddened litmus paper gave no alkaline re- 

 action, yet its existence might be suspected as derived from 

 the wax ; and as metallic vessels were obviously objectionable, 

 I sought other means of determining the part played by 

 the hydrogen in this combination. I repeated experiment 

 2, keeping heated, below the boiling point, the vessel con- 

 taining the zinc and mercury; my galvanometer gave a 

 tolerably constant deflection of 60 degrees, and the mercury 

 evolved much more hydrogen than when the apparatus was 

 cold. Again, I kept for some time a strip of well-cleaned pla- 

 tinum 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 per- 

 fect 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 f. 



* The current is not so completely null when dilute muriatic acid is the 

 electrolyte, as it is with sulphuric or phosphoric acid ; perhaps the sulphur 

 or phosphorus contributes to the effect; the difference is however but trifling. 



f Tiie probability of a temporary combination of hydrogen with mer- 

 cury throws some light upon the movements of mercury 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 }ield their hydrogen, and so on of the rest. In electrolyzation with 

 a mass of mercury as negative electrode, the hydrogen is all evolved at 

 the parts most distant from the positive electrode. 



