Elements of electro-metallurgy, or, The art of working in metals by the galvanic fluid ... / [Alfred Smee].

  • Alfred Smee
Date:
1841
Catalogue details

Licence: Public Domain Mark

Credit: Elements of electro-metallurgy, or, The art of working in metals by the galvanic fluid ... / [Alfred Smee]. Source: Wellcome Collection.

    40/204 page 6
    — r £ 6 EXCITING FLUID OF GALVANIC BATTERIES. electricity will be likewise doubled. However, the extent of surface of the positive metal, within certain limits, is not of so much consequence, although too great a deficiency of this is attended with detriment. (17.) One circumstance must be noticed, that every point of the negative offers a radiating point tothe positive metal; for every point not so situated, is much less active, and some- times even perfectly inactive. In different cases, this property is shown more or less strikingly; for if the hydrogen be removed in its nascent state, it will, under the combined action of its adhesion and elasticity, manifest itself at a great distance from the positive metal, and even quite without the sphere of its radiation, as is the case where the back of a piece of metal is active, while the front alone is opposite to the fluid. When very smooth metals are used, it will also pass to a great dis- tance; but when a metal is prepared in the manner I have hereafter to point out, by platinum, the gas will only be given off from a small extent, though very violently, when touched by the point of a fine zinc wire. (18.) A relation exists between the power, and the distavea interposed between the electro-positive and negative metals ; for the nearer these can be brought together, the greater the quantity of electricity developed; though the intensity is not influenced by the difference of arrangement. (19.) The function of the acid solution has already been partially explained; for we have before mentioned that the water is decomposed, the hydrogen being evolved at the negative metal, and the oxygen combining with the zine, to » form oxide of zinc. The acid now comes into play, and in addition to its adding considerable conducting power to the solution, it removes the oxide to form the sulphate of zine. . (20.) Whatever exciting fluid is employed to charge the battery, its efficacy depends upon the same principles; but the intensity varies with each variation in the foreign body _ placed in the water; thus dilute nitric acid, dilute sulphuric
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