Copy 1, Volume 1

Hand-book of chemistry / Translated by Henry Watts.

  • Gmelin, Leopold, 1788-1853
Date:
1848-1872
Catalogue details

Licence: Public Domain Mark

Credit: Hand-book of chemistry / Translated by Henry Watts. Source: Wellcome Collection.

    439/562 (page 415)
    inconsiderable in comparison with the resistance R in the individual cir- cuits, it nearly vanishes in the formula, and there remains eer aioe nara eer hear: oe din te er ee a te that is to say: the quantity of the current is the same, whether it proceeds from one pair or from several. But if the resistance of the conductor which closes the circuit is con- siderable—e. g., from the interposition of water, &c,—then, Q increases considerably with the number of pairs—because then Fan gives a much nA nR+ Pr The development of this subject may be found in Ohm’s Memoirs already cited on page 307; likewise in Ohm’s Galvanische Kette, Berlin, 1827; Fechner, Maassbestimmungen der galvanischen Kette, Leipzig, 1831 ; Pouillet (Pogg. 42, 281); Henrici (Pogg. 53, 277). smaller quotient than Quantity of the Electric Current of a Galvance Battery. With amalgamated zinc and platinum in dilute sulphuric acid, the quantity of the current is not increased by augmenting the number of pairs. One pair, by the oxidation of one atom of zinc—provided the connecting wire be thick enough to transmit the feeble current without diminution—supplies as much electricity in the form ofa current, as 1000 pairs would supply by the oxidation of 1000 atoms of zinc. In all the cells, equal quantities of water are decomposed and equivalent quantities of zine dissolved, viz. 32°5 parts (1 At.) of zine, to 1 part (1 At.) of hydrogen gas evolved. (Faraday.) A number of pairs does not produce a stronger deflection of the gal- yanometer than a single pair; one pair acts more, another less strongly. The sum of the effects [quantities] of the single pairs divided by the number of pairs gives the effect [quantity] of the pile: hence, a larger pair added to a number of smaller pairs increases the action,—a smaller pair diminishes it. (Marianini.) Even though the several pairs, from differences in extent of surface or in the nature of the liquid, should individually produce different quanti- ties of electricity,—still, all the currents which pass from the electro- negative to the electro-positive metals of the several pairs, after the union of these pairs, are mathematically equal. The quantity of elec- tricity in the current of a battery is greater than that of the weakest pair taken singly,—because, when this pair is joined to the battery, no more pure chemical action takes place in it. A very feeble pair is to be regarded only as an interposed plate (vid. seq.) which weakens the cur- rent; and the quantity of the current remains the same, even when the weak pair is introduced in the reverse order. (De la Rive.) | The quantity of the current of a pile charged with dilute sulphuric acid is very much diminished, when this pile is united in the proper order with another containing only water. (Schénbein.) _ If 10 pairs of amalgamated zine plates and platinum plates are sepa- rately immersed in dilute sulphuric acid, different quantities of hydrogen gas are evolved in a given time on the surfaces of the several platinum plates, the variation amounting to about 4 of the whole. But when all the 10 pairs are united into a battery, the quantity of gas evolyed on