“In front of the oblong trough, or box, described by your correspondent, a lamp is placed, and that side of the box next the lamp is of ground glass, through which the light is transmitted for the purpose of illuminating the letters. The oblong box is open at the top, but a plate of glass is interposed between the letters and the spectator, through which the latter reads off the letters as they are successively exposed to his view. At the opposite side of the room, a small key board is placed, (similar to that of a piano forte, but smaller,) furnished with twelve keys; eight of these have each three letters of the alphabet on their upper surfaces, marked A, B, C; D, E, F; and so on. By depressing these keys in various ways, the signals or letters are produced at the opposite desk, as previously described, how this is affected is not described by the inventor, as he intimated that the construction of certain parts of the apparatus must remain secret. By the side of the key board, there is placed a small galvanic battery, from which proceeds the wire, 25 yards in length, passing round the room. Along this wire the shock is passed, and operates upon that part of the apparatus which discloses the letters or signals. The shock is distributed as follows: The underside of the signal keys are each furnished with a small projecting piece of wire, which, on depressing the keys, is made to enter a small vessel, filled with mercury, placed under the outer ends of the row of keys; a shock is instantly communicated along the wire, and a letter, or signal, is as instantly disclosed in the oblong box. By attentively looking at the effect produced, it appeared as if a dark slide were withdrawn, thereby disclosing the illuminated letter. A slight vibration of the (apparent) slide, occasionally obscuring the letter, indicated a great delicacy of action in this part of the contrivance, and although not distinctly pointed out by the inventor, is to be accounted for in the following manner: when the two ends of the wire of the galvanic apparatus are brought together, over a compass needle, the position of the needle is immediately turned, at right angles, to its former position; and again, if the needle is placed with the north point southward, and the ends of the wire again brought over it, the needle is again forced round to a position at right angles to its original one. Thus, it would appear, that the slide or cover over the letters, is poised similarly to the common needle, and that by the depression of the keys, a shock is given in such a way as to cause a motion from right to left, and vice versa, disclosing those letters, immediately, under the needle so operated upon.”
Alexander’s Electric Telegraph,
from the (Scotsmen) Mechanic’s Magazine, Nov. 1837.
“A model to illustrate the nature and powers of this machine was exhibited on Wednesday evening at the Society of Arts in Edinburgh. The model consists of a wooden chest, about five feet long, three feet wide, three feet deep at the one end, and one foot at the other. The width and depth in this model are those which would probably be found suitable in a working machine, but it will be understood that the length in the machine may be a hundred or a thousand miles, and is limited to five feet in the model, merely for convenience. Thirty copper wires extend from end to end of the chest, and are kept apart from each other. At one end (which, for distinction’s sake, we shall call the south end) they are fastened to a horizontal line of wooden keys, precisely similar to those of a piano forte; at the other, or north end, they terminate close to thirty small apertures, equally distributed in six rows of five each, over a screen of three feet square, which forms the end of the chest. Under these apertures on the outside, are painted, in black paint, upon a white ground, the twenty-six letters of the alphabet, with the necessary points, the colon, semicolon, and full point, and an asterisk, to denote the termination of a word. The letters occupy spaces about an inch square. The wooden keys, at the other end, have also the letters of the alphabet, painted on them in the usual order. The wires serve merely for communication, and we shall now describe the apparatus by which they work.
This consists, at the south end, of a pair of plates, zinc and copper, forming a galvanic trough, placed under the keys; and at the north end, of thirty steel magnets, about four inches long, placed close behind the letters painted on the screen. The magnets move horizontally on axes, and are poised within a flat ring of copper wire, formed of the ends of the communicating wires. On their north ends they carry small square bits of black paper, which project in front of the screen, and serve as opercula, or covers, to conceal the letters. When any wire is put in communication with the trough at the south end, the galvanic influence is instantly transmitted to the north end; and in accordance with the well known law, discovered by Oersted, the magnet at the end of that wire instantly turns round to the right or left, bearing with it the operculum of black paper, and unveiling a letter. When the key, A, for instance, is pressed down with the finger at the south end, the wire attached to it is immediately put in communication with the trough; and at the same instant, letter A, at the north end is unveiled, by the magnet turning to the right, and withdrawing the operculum. When the finger is removed from the key, it springs back to its place; the communication with the trough ceases; the magnet resumes its position, and the letter is again covered. Thus by pressing down with the finger, in succession, the keys corresponding to any word or name, we have the letters forming that word, or name, exhibited at the other end; the name Victoria, for instance, which was the maiden effort of the telegraph on Wednesday evening.”
Fig. 65.
The above description is all that we have been able to obtain in relation to this plan of an electric telegraph and here introduce, [figure 65], to illustrate it. The 30 needles are represented on the screen, each carrying a shade, which conceals the letter when the needle is vertical. The needle belonging to the letter F, is, however, deflected, and the letter is exposed. The screen is supposed to be at the receiving station. To the left hand of the screen, 30 wires, e, e, are seen joined to one, a; the other 30 wires, d, d, are seen below the screen. These wires may be supposed to extend many miles, and to be joined with their corresponding wires, c, and also v, v, of the transmitting station, where it will be observed, the wire, c, connects with the battery at one pole, and from the other pole a wire is continued and soldered to the metallic plate, o, o, which extend under all the 30 keys, i, i. These keys are each insulated, at their extremity, by being fastened to a wooden standard, L, L, to which a wire is soldered. Now, suppose the key, F, is pressed down, (the sixth key from the left,) the fluid then passes from the battery, B, through the wire to o, the plate; then to the key in contact with it; then to its wire, marked by the arrow; thence through the extended wire to its corresponding wire at the receiving station, denoted by the arrow; then through the coils of the multiplier, deflecting the needle, F; then returns through its wire, at the left, to the common wire, a; then through the extended wire to C, and the battery, of the transmitting station. In this manner any letter upon the screen may be indicated.
Extract from the Report of the Academy of Industry,
in reference to a suggestion of M. Amyot of an Electric Telegraph.
“M. Amyot announced, in a letter addressed to the Academy of Sciences, in April, 1838, that he also proposed to construct an electric telegraph. It was to consist of a single current, which would move a single needle, which needle would of itself write on paper, with mathematical precision, the correspondence which might be transmitted to the other extremity, by a simple wheel on which it should be written by means of points, differently spaced, the same as they are on the barrels of portable organs. In order to send any news then, he required to write, by means of movable characters, which must be constructed in a certain manner, and immediately it would be repeated and transcribed at the place where he wished to address it, on paper, which could be put into the hands of persons specially employed to transmit despatches. But all that method of execution, which it seems ought to move is clock work, not having been sufficiently described by the author, the most vague uncertainty yet reigns as to the true construction of that apparatus, which appears to us to have been for M. Amyot, rather the occasion, than the end, of this communication; for indeed he attempted to make the possibility admitted of establishing a universal telegraphic language of his invention.”