References.—Phil. Mag., Vol. IV for 1828, p. 463; eighth “Britannica,” Vol. XXI. p. 619.
A.D. 1815.—Gregory (Olinthus Gilbert), LL.D., Professor of Mathematics at the Royal Military Academy, Woolwich, in his “Treatise on Mechanics,” London, 1815 (Vol. II. pp. 442–449), describes the methods of transmitting distant signals introduced by Polybius, the Marquis of Worcester, Robert Hooke, Amontons and Chappe, and alludes to an improved telegraph described in the “Gentleman’s Magazine,” as well as to the so-called nocturnal telegraph, of which an account is to be found in the Repertory of the Arts and Manufactures (“Biographie Générale,” Tome XXI. p. 903).
A.D. 1815.—In the Philosophical Magazine (Vol. XLVI. pp. 161, 259), will be found an account of the electrical experiments of M. De Nelis, of Mechlin, or Malines, in the Netherlands, with an extension of them by George J. Singer and Andrew Crosse.
These allude to many investigations made during previous years by M. De Nelis, who reported upon them to Mr. Tilloch and to M. de la Méthérie, and which show “very remarkable and permanent evidence of the expansive power of the electric charge.” Singer adds: “It is difficult to contemplate such extraordinary mechanical effects without admitting that the power by which they are produced has at least the leading characteristics of a material substance.” At p. 127, Vol. XLVIII of the Phil. Mag., is an account of some further electrical experiments of M. De Nelis, one of which is intended to improve the simple current with an apparatus not insulated by discs. In this communication, which bears date July 10, 1815, he discourses upon the theory of the two fluids.
A.D. 1816.—Coxe (John Redman), M.D., Professor of Chemistry in the University of Pennsylvania, is the second to propose a system of transmitting signals, based, like Sömmering’s (A.D. 1809), upon the discovery of Nicholson and Carlisle.
In the first series of Dr. Thos. Thomson’s Annals of Philosophy for 1816 (not 1810), Vol. VII. pp. 162, 163, will be found Coxe’s letter “On the Use of Galvanism as a Telegraph,” wherein he says:
“I have contemplated this important agent as a probable means of establishing telegraphic communication with as much rapidity, and perhaps less expense, than any hitherto employed. I do not know how far experiment has determined galvanic action to be communicated by means of wires; but there is no reason to suppose it confined as to limits, certainly not as to time. Now, by means of apparatus fixed at certain distances, as telegraphic stations, by tubes for the decomposition of water, metallic salts, etc., regularly arranged, such a key might be adopted as would be requisite to communicate words, sentences or figures, from one station to another, and so on to the end of the line.... As it takes up little room, and may be fixed in private, it might in many cases of besieged towns, etc., convey useful intelligence with scarcely a chance of detection by the enemy. However fanciful in speculation, I have no doubt that, sooner or later, it will be rendered in useful practice. I have thus, my dear sir, ventured to encroach on your time with some crude ideas that may serve perhaps to elicit some useful experiments in the hands of others. When we consider what wonderful results have arisen from the first trifling experiments of the junction of a small piece of silver and zinc in so short a period, what may not be expected from the further extension of galvanic electricity? I have no doubt of its being the chief agent in the hands of nature in the mighty changes that occur around us. If metals are compound bodies, which I doubt not, will not this active principle combine their constituents in numerous places so as to explain their metallic formation; and if such constituents are in themselves aeriform, may not galvanism reasonably tend to explain the existence of metals in situations in which their specific gravities certainly do not entitle us to look for them?”
Coxe does not appear, however, to have at any time made satisfactory experiments, and his systems were considered impracticable until worked out by Alex. Bain during the year 1840.
At pp. 99–110, Vol. II of Dr. Coxe’s Emporium of Arts and Sciences, Philadelphia, 1812, will be found his illustrated “Description of a Revolving Telegraph,” for conveying intelligence by figures, letters, words or sentences, upon which plan, he says, he constructed a small telegraph that worked “readily and appropriately, although by no means fitted with the various pulleys, etc., to facilitate the motion of the ropes.”
References.—For full explanation of Coxe’s systems, see L. Turnbull, “Elect. Mag. Tel.” Highton’s “Electric Telegraph,” p. 39; Jour. Franklin Inst., Vol. XXI. for 1851, pp. 332, 333; Comptes Rendus for 1838, Vol. VII. pp. 593, etc.; Sci. Am. Supp., Nos. 404, p. 6446, and 453, p. 7234; Alfred Vail, “The American Electro-Magnetic Telegraph,” pp. 128, 129; Prime’s “Life of Morse,” p. 263.