_Directions for trimming the Euphaneron Lamp._--Remove the lamp from the lantern, carefully clean the front glass and the mirror. Turn back the combustion-chamber on its hinge, so as to expose the tops of the wicks. These should be cut quite smooth and straight, without any projecting filaments. The cistern should be nearly filled with the best mineral oil, and the wicks turned up a little way and lit. The combustion chamber should be now restored to its place, the lamp put into the lantern, and the chimney fixed on. The wicks should then be gradually raised as high as they will bear without smoking. In putting the oil into the lamp care should be taken not to spill any on the outside. The general directions already given for showing the pictures are then to be followed in using the Euphaneron.
The lanterns that we have hitherto been describing have been those capable of exhibiting single pictures only; we have now to explain the production of dissolving views.
Dissolving views, as the name implies, is an exhibition of pictures in which there is a fading away of one and the appearance of another, as though the one picture grew out of the wreck of the other. To produce these results, two lanterns of similar size are required (see Fig. 4), together with some contrivance for diminishing the light forming the first picture, until that has quite faded away, simultaneously allowing that forming the second picture to fall upon the screen until this one has arrived at its complete intensity, and the first picture is no longer seen. This latter contrivance is known as the mechanical dissolver, and it consists of two serrated plates attached to a movable bar fixed to the front edge of the base upon which the lanterns are supported. These plates come immediately in front of the lanterns, and require to be so arranged that when the whole of the light from one lantern is seen on the screen, the light from the other is entirely stopped. By means of a rack and pinion motion, the plates can be moved simultaneously, and each lantern alternately closed and opened.
In order to make the discs of light produced by the two lanterns coincident, the lanterns must be slightly inclined towards each other.