A manual of electro-metallurgy / By George Shaw.

  • Shaw, George
Date:
1844
Catalogue details

Licence: Public Domain Mark

Credit: A manual of electro-metallurgy / By George Shaw. Source: Wellcome Collection.

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    may be resolved into their constituent elements by a single pair. 59. A case'will, perhaps, make the matter more clear. Suppose we have a battery consisting of ten cells, and that water be made the medium of communication between its extremes, as much water will be decomposed by this instru- ment as by one of a hundred pairs, supposing them to be similarly circumstanced in every respect. This, at first sight, appears paradoxical ; but an examination of the nature of the chemical action in the voltaic battery will remove every difficulty. 60. The annexed diagram, fig. 2, represents a single voltaic Fig. 2. pair, consisting of a plate of zinc, a, and another of cop- a ‘aq \\ per, &, immersed in a vessel oe ——=—// of dilute sulphuric acid; a wire from the zinc is con- nected with a plate of platinum, c, in a second vessel, contain- ing dilute acid; and a wire from the copper is attached to another plate of platinum, d, also in the acid solution. It has already been said that a single pair will not decompose water; but in this illustration we will suppose it to pos- sess that power (for, by a slight modification, it may be made to do so), as we prefer that, in this experiment, water should be the compound decomposed. ‘The voltaic current, then, originating at the surface of the zinc, gives rise to the combination of oxygen with that metal; while hydrogen escapes at the surface of the copper ; we will suppose the cur- rent passing from the copper through its wire to the platinum plate in the second vessel, thence through the liquid to the other platinum plate, and through its wire to the zinc. 61. Now, in tracing the current through the battery, it will be observed that oxygen is that element of the decomposed water which occurs at the surface from which the current
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