INACTION OF AMALGAMATED ZINC. 239 



to complete the circuit, all action is arrested, as in the case of 

 pure zinc. The fact of amalgamated zinc being positive with 

 respect to common zinc, of its precipitating copper from its 

 solutions, and other anomalies, are also explained by these 

 experiments. 



As in a common voltaic combination of zinc and mercury 

 this effect is complicated by the variety of cations which are 

 transferred to the negative metal, for instance, hydrogen, zinc, 

 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 sucr- 

 ceeded in purifying water of alkaline matters, but the affinity 

 of mercury for the alkaline metals gave me some hopes of 

 attaining this object with less expensive means ; 'to this end I 

 submitted to electrolysation for five days, in a vessel of bees- 

 wax, distilled water acidulated with pure sulphuric acid ; the 

 negative electrode, of amalgamated copper, terminating in a 

 mass of mercury. At the end of this period I removed the 

 mercury, substituting a fresh portion of the same metal which 

 was perfectly pure, and renewed the electrolysation for two 

 hours ; I then quickly enclosed this last mercury in a tube 

 with the purified water ; it always evolved a small quantity of 

 hydrogen, 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 reaction, 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 ex- 

 periment 2, keeping heated, below the boiling point, the 

 vessel containing the zinc and mercury ; my galvanometer 

 gave a tolerably constant deflection of sixty degrees, and the 

 mercury evolved much more hydrogen than when the appa- 

 ratus was cold. Again, I kept for some time a strip of \vell- 



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

 trolyte, as it is with sulphuric or phosphoric acid ; perhaps the sulphur or phos- 

 phorus contributes to the effect ; the difference is, however, but trifling. 



