The two lanterns are different, on account of the unlike uses to which they are to be put.  One of them is a hand-lamp that permits of making a quick preliminary exploration.  The second is to be fixed by a socket beneath it to a pole that is placed along the shafts of the carriage.  This lantern, upon being thrust into a chimney, shaft, or well, permits of a careful examination being made thereof.  As the handle terminates in a point; it may be stuck into the ground, to give a light at a sufficient height to illuminate the surroundings.

The hand lantern consists of a base, P, provided with three feet.  At the top there is a threaded circle to which is attached a movable handle, K, that is screwed on to a ring, C. These three pieces, which are of bronze, are connected by 12 steel braces, E, that form a protection for the glass, M. The lantern is closed above by a thick glass disk, G. The luminous rays are therefore capable of spreading in all directions.  Tight joints are formed at every point by rubber or leather washers.

[Illustration:  FIG. 6.—­LANTERN BOX (Scale 1/10).]

In the center of the lantern is placed the incandescent lamp.  This is held in a socket, and is provided with two armatures to which the platinum wires are soldered.  Two terminals, b, are affixed to the lamp socket.  Beneath the lantern there is a cylindrical box provided with a screw cap.  In one side of this box there is a tubulure that gives passage to the electric cable whose conductors are fastened to the terminals.  A conical rubber sleeve, R, incloses the cable, which is pressed by the screw cap, S. A special spring, Y, attached at one end to the top of the lantern, and at the other to the cable, X, is designed to deaden the too sudden shocks that the lantern might be submitted to, and that would tend to pull out the cable.

As a result of the peculiar arrangement of this lantern, the lamp is constantly surrounded with a certain quantity of air that would certainly suffice to consume the carbons in case of a breakage of the globe without allowing any lighted particles to escape to the exterior.  Besides, should the terminals become unscrewed, and should the conductors thus rendered free produce sparks, the latter would be prevented from reaching the exterior by reason of the absolute tightness of the box.  In case the incandescent lamp should get broken, the only inconvenience that would attend the accident would be that the man who held the lantern would be for a moment in the dark.  When he reached the carriage, it would be only necessary for him to take off the glass disk, take the broken lamp out of its socket, insert a new one, and then put the glass top on again.—­Le Genie Civil.

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Voltaic batteries containing solutions of ammonium chloride and zinc chloride can, according to the recent researches of M. Onimus, be converted into dry piles by mixing these solutions with plaster of Paris, and allowing the mixture to solidify.  If mixtures of ferric oxide and manganese peroxide with plaster of Paris are employed, the electromotive force is slightly higher than with plaster of Paris alone; and when ferric oxide is used, the battery quickly regains its original strength on breaking the circuit.  When the battery is exhausted, the solid plaster of Paris has simply to be moistened again with the solution.