The thunder and lightning effect is somewhat complicated, especially the thunder, which may be regarded as the result of the combination of a number of effects. First a large piece of sheet iron is shaken, which produces an imitation of sharp, rattling thunder. This fails to give the dull roar, a reverberation which is usually heard in storms. To produce this effect a heavy box frame is made, and over it is tightly drawn a calf skin. Upon this the stage hand operates with a stick, one end of which is padded and covered with chamois skin. This is called the thunder drum, and when accompanied with a flash of lightning produced with the aid of a magnesium flash torch renders the illusion very realistic. Often two thunder drums are used at the same time. Then the “rumble cart” is also used. The rumble cart is a box filled with some heavy material, and mounted upon irregularly shaped wheels.
RUMBLE CART.
Our [engraving] shows a rumble cart as used in the Paris Opera House. With this a little wind is added from the wind machine, and the rain effect is sometimes worked simultaneously. The result of this complicated effect is very good, and, of course, the effect may be varied as the stage manager may think proper for the opera.
In large opera houses a more complicated system is employed than those which we have just described. It is usually placed against the wall of the third fly gallery. It consists of a kind of cabinet with five or six slanting shelves. On each shelf are kept a half dozen cannon balls which are retained in place by hinged doors. When the signal is given, the stage hands open the doors of one or more compartments, and the balls drop down into a zinc-lined trough, which is some twenty feet long. The trough being built with inequalities of surface, the effect is enhanced. At the end of the trough the balls drop through the flooring to the gallery below by means of special slants. Arrangements are provided by which the balls can be stopped before they pass through the floor. It will readily be seen that by regulating the number of balls almost any thunder effect can be produced.
LIGHTNING.
Lightning is produced in a number of ways, of which the following is an example. A metal box having a large opening in the top is provided. At the bottom is placed an alcohol lamp having a wide-spreading flame. Immediately above the flame is a shelf or partition punched with fine holes. This is, of course, heated very hot by the flame. The mixture which is used to give the effect of lightning consists of three parts of magnesium powder and one part of potassium chlorate. This is poured upon the heated grill, through the top of the metal box. The sudden combustion of the composition produces very vivid flashes of lightning. A similar device has long been used by photographers for taking instantaneous photographs in dark places or at night.