Faraday As A Discoverer [20]
the proportion of 8 to 1, to form water. Calling the equivalent, or as it is sometimes called, the atomic weight of hydrogen 1, that of oxygen is 8; that of water is consequently 8 + 1 or 9. Now if the quantity of water decomposed in Faraday's experiment be represented by the number 9, or in other words by the equivalent of water, then the quantity of tin liberated from the fused chloride is found by an easy calculation to be 57.9, which is almost exactly the chemical equivalent of tin. Thus both the water and the chloride were broken up in proportions expressed by their respective equivalents. The amount of electric force which wrenched asunder the constituents of the molecule of water was competent, and neither more nor less than competent, to wrench asunder the constituents of the molecules of the chloride of tin. The fact is typical. With the indications of his voltameter he compared the decompositions of other substances, both singly and in series. He submitted his conclusions to numberless tests. He purposely introduced secondary actions. He endeavoured to hamper the fulfilment of those laws which it was the intense desire of his mind to see established. But from all these difficulties emerged the golden truth, that under every variety of circumstances the decompositions of the voltaic current are as definite in their character as those chemical combinations which gave birth to the atomic theory. This law of Electro-chemical Decomposition ranks, in point of importance, with that of Definite Combining Proportions in chemistry. Footnotes to Chapter 6 [1] I copy these words from the printed abstract of a Friday evening lecture, given by myself, because they remind me of Faraday's voice, responding to the utterance by an emphatic 'hear! hear!'--Proceedings of the Royal Institution, vol. ii. p. 132. [2] In 1838 he expresses himself thus:--'The word current is so expressive in common language that when applied in the consideration of electrical phenomena, we can hardly divest it sufficiently of its meaning, or prevent our minds from being prejudiced by it.'-- Exp. Resear., vol. i. p. 515. ($ 1617.) [3] This conclusion needs qualification. Faraday overlooked the part played by ozone. Chapter 7. Origin of power in the voltaic pile. In one of the public areas of the town of Como stands a statue with no inscription on its pedestal, save that of a single name, 'Volta.' The bearer of that name occupies a place for ever memorable in the history of science. To him we owe the discovery of the voltaic pile, to which for a brief interval we must now turn our attention. The objects of scientific thought being the passionless laws and phenomena of external nature, one might suppose that their investigation and discussion would be completely withdrawn from the region of the feelings, and pursued by the cold dry light of the intellect alone. This, however, is not always the case. Man carries his heart with him into all his works. You cannot separate the moral and emotional from the intellectual; and thus it is that the discussion of a point of science may rise to the heat of a battle-field. The fight between the rival optical theories of Emission and Undulation was of this fierce character; and scarcely less fierce for many years was the contest as to the origin and maintenance of the power of the voltaic pile. Volta himself supposed it to reside in the Contact of different metals. Here was exerted his 'Electro-motive force,' which tore the combined electricities asunder and drove them as currents in opposite directions. To render the circulation of the current possible, it was necessary to connect the metals by a moist conductor; for when any two metals were connected by a third, their relation to each other was such that a complete neutralisation of the electric motion was the result. Volta's theory of metallic contact was so clear, so beautiful, and apparently so complete, that the best intellects of Europe accepted it as the expression of natural law. Volta himself knew nothing of the chemical phenomena of the pile; but