On April 19 and 20 Davy was again at work with the battery of 520 pair of plates.
He began thus: ‘Indications of the decomposition of muriatic acid. To use every effort to ensure accuracy in the results.’
‘A given quantity of muriatic acid gas was acted upon by dry charcoal; there was continued vivid light in the galvanic circuit. The action was continued for ten minutes; when a little water was added no absorption took place, so that all the muriatic acid gas was decomposed. Some other experiments were made with dry muriate of lime and mercury and with a solution of muriate of lime, strontium, and soda.’
On June 30 he had a paper read at the Royal Society on the ‘Decomposition of the Earths Strontia, Lime, Magnesia, by Means of Iron at the Negative End of the Battery.’ Berzelius having mentioned in a letter that he had succeeded by using mercury as the negative pole, Davy repeated Berzelius’s experiment, and decomposed alumina and silica by an amalgam of mercury and potassium at the negative end of the battery.
On July 11 he laid before the managers of the Royal Institution the following paper:
A new path of discovery having been opened in the agencies of the electrical battery of Volta, which promises to lead to the greatest improvements in chemistry and natural philosophy and the useful arts connected with them; and since the increase of the size of the apparatus is absolutely necessary for pursuing it to its full extent, it is proposed to raise a fund by subscription for constructing a powerful battery, worthy of a national establishment and capable of promoting the great objects of science.
Already in other countries public and ample means have been provided for pursuing these investigations. They have had their origin in this country, and it would be dishonourable to a nation so great, so powerful, and so rich if, from the want of pecuniary resources, they should be completed abroad.
An appeal to enlightened individuals on this subject can scarcely be made in vain. It is proposed that the instrument and apparatus be erected in the laboratory of the Royal Institution, where it shall be employed in the advancement of this new department of science.
The Managers’ Minutes then say:
The above paper having been laid before the board of managers, they felt it their indispensable duty instantly to communicate the same to every member of the Institution, lest the slightest delay might furnish an opportunity to other countries for accomplishing this great work, which originated in the brilliant discoveries recently made at the Royal Institution.
Lord Dundas, W. Watson, Thomas Bernard, and C. Hatchett, the managers present, agreed to subscribe to this undertaking, and ordered that a book be opened at the steward’s office for the purpose of entering the names of all those who may wish to contribute towards this important national object.[37]
The sum wanted was soon raised, and Davy thus described the battery:
‘It consists of 200 instruments, connected together in regular order, each composed of ten double plates, arranged in cells of porcelain, and containing in each plate thirty-two square inches; so that the whole number of double plates is 2,000, and the whole surface 128,000 square inches. This battery was charged with sixty parts water and one part of nitric acid. It gave a spark from charcoal points through four inches of air.’