“The chemical agency of galvanism, exerted on _fluid_ conductors, placed in the circuit between the poles of the battery, is very remarkable. Among the simplest of its effects is the resolution of water into its two gaseous elements, oxygen and hydrogen. The discovery of this fact is due to the united researches of Mr. Nicholson and Mr. Carlisle, and was one of the immediate consequences of the invention of the pile by Volta. The most convenient mode of exhibiting the decomposition of water by the Voltaic battery, is to fill, with water, a glass tube; to each end of which, a cork has been fitted so as to confine the water, and to introduce into the tube two metallic wires, by passing one, at each end, through the cork which closes it, allowing the extremities of the wires, that are in the water, to come so near each other as to be separated by an interval of only a quarter of an inch. The wires being then respectively made to communicate with each of the two poles of a Voltaic battery, the following phenomena will ensue. If the wire connected with the positive pole of the battery consists of an oxidable metal, it is rapidly oxidated by the water surrounding it; while, at the same time, a stream of minute bubbles of hydrogen gas arises from the surface of the other wire, which is in connection with the negative pole. But if we employ wires made of a metal which is not susceptible of oxidation by water, such as gold or platina, gas will be extricated from both the wires, and, by means of a proper apparatus may be collected separately.” We shall now see that these two discoveries, viz. the Voltaic pile, and the decomposition of water by the agency of the former are the bases of a plan _for telegraphic_ purposes. _Samuel Thomas Soemmering’s Description of his Voltaic Electric Telegraph, invented in 1809._ [Illustration: FIG. 36.] “The fact that the decomposition of water may be produced with certainty and instantaneously, not only at short, but at great distances from the Voltaic pile, and that the decomposition may be sustained for a considerable time, suggested to me the idea, that it might be made subservient for the purposes of transmitting intelligence in a manner superior to the plan in common use, and would supersede them. My engagements were such that I have only been able to test the practicability of my plan upon a small scale, and herewith submit, for the Academy’s publication, an account of the experiment.