By the discoveries of Galvani the physicians and physiologists were greatly excited, and believed that by this new vital power the nature of all kinds of nervous diseases could be explored and the remedy applied. Volta’s discovery excited the chemists. If two dissimilar metals could be decomposed and power at the same time produced they contended that practical work might be done with the force. In 1800 Nicholson and Carlisle decomposed water by passing the electric current through the same; Ritter decomposed copper sulphate, and Davy decomposed the alkalies, potash and soda. Thus the art of electrolysis--the decomposition of substances by the galvanic current, was established. Later Faraday laid down its laws. Naturally inventions sprung up in new forms of batteries. The pile and cup battery of Volta had been succeeded by the trough battery--a long box filled with separated plates set in dilute acid. The trough battery was used by Sir Humphry Davy in his series of great experiments--1806-1808--in which he isolated the metallic bases, calcium, sodium, potassium, etc. It consisted of 2000 double plates of copper and zinc, each having a surface of 32 square inches. With this same trough battery Davy in 1812 produced the first electric carbon light, the bright herald of later glories. Among the most noted new batteries were Daniell’s, Grove’s and Bunsen’s. They are called the “two fluid batteries,” because in place of a single acidulated bath in which the dissimilar metals were before placed, two different liquid solutions were employed. John Frederick Daniell of London, noted for his great work, _Meteorological Essays_, and other scientific publications, and as Professor of Chemistry in King’s College, in 1836, described how a powerful and constant current of electricity may be continued for an unlimited period by a battery composed of zinc standing in an acid solution and a sheet of copper in a solution of sulphate of copper. Sir William Robert Grove, first an English physician, then an eminent lawyer, and then a professor of natural philosophy, and the first to announce the great theory of the Correlation of Physical Forces, in 1839 produced his battery, much more powerful than any previous one, and still in general use. In it zinc and platinum are the metals used--the zinc bent into cylindrical form and placed in a glass jar containing a weak solution of sulphuric acid, while the platinum stands in a porous jar holding strong nitric acid and surrounded by the zinc. Among the electrical discoveries of Grove were the decomposition by electricity of water into free oxygen and hydrogen, the electricity of the flame of the blow-pipe, electrical action produced by proximity, without contact, of dissimilar metals, molecular movements induced in metals by the electric current, and the conversion of electricity into mechanical force.