1851 Great Exhibition: Official Catalogue: Class X.: Alfred Brett
422. BRETT, ALFRED, 138 Holborn Bars — Proprietor.
Brett and Little's patent electric telegraph, alarum bell, bell handle, and battery.
The electric telegraph. The various letters or numerals represented on the dial are made by the motions of either or both of the indicators; the number of the motions for each letter or numeral is defined by the figures on the centre of the dial, commencing at all times with the indicator on the side next the letter or numeral, and when both indicators are used, finishing with the opposite one. The helices are double and of a circular form, and the magnet is in the form of a ring or horseshoe, suspended in the centre of the helices, and is deflected either to the right or to the left, according to the direction of the current. The poles of the magnet being equidistant from the earth, the magnet is rendered astatic, and not affected by the terrestrial magnetism.
These magnets move parallel with the coils of wire and planes of electricity. The indicators not being magnets are perfectly free from vibration, and the indication is therefore distinct and certain.
The alarum bell, for calling the attention of the attendant, being liberated by a motion similar to that of the telegraph, gives three distinct blows; and should it, by any chance, be liberated by a current of atmospheric electricity, the apparatus would not be deranged.
The deflector on the left of the instrument enables the current to be transferred from the telegraph to the bell, and vice versa; and it can also be used in case of an instrument getting injured, to pass the current along the line, without stopping the communications at other stations; with this, one wire only is required to enable every station on a line of railway to communicate with the whole by means of one instrument only at each station.
The battery is of the ordinary form, except that the cells are of porcelain and separate, and the plates are connected with binding screws.
By the use of an underground arrangement of conductors (as exhibited in combination) the cost in the first instance, with wire encased in lead, is very little more than posts with wires suspended in the air; and with wire, encased in gutta percha only, much less; while the cost of maintenance is greatly reduced, and the liability of interference from atmospheric influence avoided.