He conceives also that it may be possible to obtain a measure of chemical affinity founded upon the energy of the voltaic apparatus required to destroy the chemical equilibrium. He points out that, as light and heat are the common consequences of the restoration of the equilibrium between bodies in a high state of opposite electricities, so it is perhaps an additional circumstance in favour of his theory to state that heat and light are likewise the result of all intense chemical action. And as in certain forms of the voltaic battery when large quantities of electricity of low intensity act, heat is produced without light; so in slow combinations there is an increase of temperature without luminous appearance. The effect of heat in producing combination may, he assumes, be also explained according to these ideas. It not only gives more freedom of motion to the particles, but in a number of cases—e.g. tourmaline, sulphur, etc.—it seems to exalt the electrical energies of bodies.
In the eighth section he seeks to apply these principles to the mode of action of the voltaic pile, and to explain the nature of the changes which occur between the plates and the exciting fluid, and he points out that the theory in some measure reconciles the hypothetical principles of the action of the pile adopted by its inventor with the opinions concerning the chemical origin of galvanism held by the majority of British men of science at that period. At the same time, Davy argues that the facts are in contradiction to the assumption that chemical changes are the primary causes of the phenomena of galvanism. Moreover, in mere cases of chemical change—as in iron burning in oxygen, the deflagration of nitre with charcoal, the combination of potash with sulphuric acid, the amalgamation of zinc,—electricity is never exhibited.
In the concluding section he trusts that many applications of the general facts and principles thus indicated to the processes of chemistry, both in art and in nature, may suggest themselves to the philosophical inquirer. It is not improbable, he thinks, that the electric decomposition of the neutral salts in different cases may admit of economical uses. He is induced to hope that the new mode of analysis may lead to the discovery of the true elements of bodies:—
“For if chemical union be of the nature which I have ventured to suppose, however strong the natural electrical energies of the elements of bodies may be, yet there is every probability of a limit to their strength: whereas the powers of our artificial instruments seem capable of indefinite increase.”
Phenomena similar to those occurring in the voltaic cell must be produced in various parts of the interior strata of our globe, and it is very probable that many mineral formations have been materially influenced, or even occasioned, by such action. The electrical power of transference may serve to explain some of the principal and most mysterious facts in geology.
“Natural electricity has hitherto been little investigated, except in the case of its evident and powerful concentration in the atmosphere. Its slow and silent operations in every part of the surface will probably be found more immediately and importantly connected with the order and economy of nature; and investigations on this subject can hardly fail to enlighten our philosophical systems of the earth, and may possibly place new powers within our reach.”
The publication of this paper exercised a profound sensation, both at home and abroad. Berzelius, years afterwards, spoke of it as one of the most remarkable memoirs that had ever enriched the theory of chemistry—and the praise is the more significant when it is remembered that Davy had thereby seemed to have taken possession of a field of inquiry which the Swedish chemist, who was only a year younger than Davy, had been among the first to enter. Still more significant was the action of the French Institute. Bonaparte, when First Consul, had announced to the Institute his intention of founding a medal “for the best experiment which should be made in the course of each year on the galvanic fluid,” and had further expressed his desire to give the sum of sixty thousand francs “à celui qui, par ses expériences et ses découvertes fera à faire à l’electricité et au galvanisme un pas comparable à celui qu’ont fait faire à ces sciences Franklin et Volta.” A committee of the Institute, consisting of La Place, Halle, Coulomb, Hauy and Biot, was appointed to consider the best means of accomplishing the wishes of the First Consul, and twelve months after the publication of the Bakerian lecture they awarded its author the medal. Whether the Institute had the means of awarding the sixty thousand francs as well is more than doubtful, for it does not appear that the sum named by Bonaparte ever went beyond the promise of it. All that the Institute got for themselves was, as Maria Edgeworth said, “a rating all round in imperial Billingsgate.” The two countries at this period were at war, and the feeling of animosity was most bitter. Of course, there were persons who said that patriotism should forbid the acceptance of the award. Davy’s own view was more sensible and politic. “Some people,” he said to his friend Poole, “say I ought not to accept this prize; and there have been foolish paragraphs in the papers to that effect; but if the two countries or governments are at war, the men of science are not. That would, indeed, be a civil war of the worst description: we should rather, through the instrumentality of men of science, soften the asperities of national hostility.”
CHAPTER VI.
THE ISOLATION OF THE METALS OF THE ALKALIS.
However devoted Davy might be to scientific investigation, he was no less mindful of the sacred claims of the long vacation. In the summer of 1805 he went to the Lake Country, where he met Scott in company with Wordsworth; and the occasion on which the party “climbed the dark brow of the mighty Helvellyn,” and which gave rise to Scott’s well-known poem, is thus referred to by Lockhart:—