FIGS. 2 AND 3.
Finally, when the telephone is unhooked, the inductor, J, and the bell, W, are thrown out of circuit, and the telephone is interposed between d and i, that is, between L and T.—La Lumiere Electrique.
THE GERARD ELECTRIC LAMP.
In the Gerard incandescent lamp the carbons have the form of a V. They are obtained by agglomerating very finely powdered carbon, and passing it through a draw plate. At their extremity they are cemented together with a small quantity of carbon paste, and their connection with the platinum conducting wires is effected by means of a cylinder of the same paste surmounted by a cone. These couplings secure a good contact, and, by their dimensions, prevent the attachments from becoming hot and consequently injuring the carbon at this point. The cone forms a connection of decreasing section, and prevents the carbon from getting broken during carriage.
This process of manufacture permits of obtaining lamps of all intensities, from 3 candles up. The following, according to Mr. Gerard, are the consumptions of energy in each size of lamp:
Candles. Volts. Amperes.
No. 0. 10 16 1.5
" 1. 25 25 2
" 2. 50 30 2.5
It will be seen that these lamps require a relatively intense current with much less fall of potential than the Swan, for example—this being due to the diameter of the filament. But, what is an inconvenience as regards mounting, if we wish to supply them by ordinary machines (for they must be mounted in series of 3 on each derived circuit if the machine gives, as most frequently the case, 100 volts), is an advantage as regards the quality and steadiness of the light and the duration of the lamps.
