In the accompanying cut we bring together a few figures of porcelain insulators for uncovered wires placed inside or outside of houses. [Illustration: PORCELAIN INSULATORS FOR TELEGRAPH AND TELEPHONE LINES.] Figs. 1 and 2 represent simple and double channeled pulleys to be fixed against a wall, or upon a pole or a door post, by means of nails simply. Fig. 3 shows a pulley of larger dimensions for iron wires. Figs. 4, 5, and 6 show perforated insulators, that are quite convenient for holding and supporting a wire, but which are not convenient to put in position when the wire is of some length. Fig. 7 shows a device for protecting a wire that passes through a wall. Fig. 8 shows a support designed especially for small poles. It may be used either by passing the wires through the aperture or winding it around the neck of the bell. Fig. 8 shows a cleft insulator designed especially for fixing a wire in places where it must form an angle.--_La Nature_. ELECTRIC LIGHT IN THEATERS. M. Brandt places alternately, in a continuous line, forty lamps of ordinary glass, forty of green glass, and forty of red glass, making a hundred and twenty lamps in all, at the foot of the stage. Each series of forty lamps forms a separate circuit. The three series can be lighted independently, or they may be combined, in order to obtain different effects of color. For example, a delicate rose hue may be produced by simultaneously lighting the red and the white lamps; a moonlight effect, by a combination of the white and the green lamps. In order to pass gradually from the latter to full daylight, it is only necessary to increase the resistance in the green circuit while strengthening the current in the white lamps. Moreover, the two sides of the stage may be lighted independently, because the 120 lamps are again subdivided into two circuits of sixty each. We may thus have a moonlight on one side of the stage, while the other side, at the moment when an actor enters with a torch in his hand, seems to be illuminated by the reflection from the torch. When the footlights are of gas, a current of hot air ascends above the whole line of lights, forming a sort of gaseous wall between the stage and the audience, which often makes it difficult to hear the actors. This inconvenience is suppressed by electric lighting, and the opera singers are agreeably surprised at the great improvement.--_Lumiere Electr._ THE NEW DAM AT SURESNES. It was not till 1867, on the occasion of the Universal Exhibition, that a dam was constructed at Suresnes that permitted of omnibus-boat service. The effect that this dam had was to raise the water 7½ feet up stream, and to consequently suppress the natural incline of the river between Paris and Suresnes. Its action made itself felt as far as to the Austerlitz Bridge in front of the Garden of Plants.