8CI0PTIC0N MANUAL.
59
A largo plate of glass leans forward on the front of the
stage, but its edges are so hidden by the curtains that its
presence is not suspected. A “woman in white” stands
down in front, concealed from the spectators by the usual
board near the orchestra, and is highly illuminated by
the light from a magic lantern. The spectators, in the
darkness and distance, see the actors upon the stage
through the glass, and also the ghost reflected from the
glass so as to appear on the stage with the rest. The
actors do not see the spectre, but they put on the ap¬
pearance of fright for the benefit of the spectators.
The apparition vanishes as the light is withdrawn from
“ the woman in white.” The lantern is used because it
illuminates an object without diffusing light in other
directions.
On this principle we may see people in a room through
a window, with the reflected images of parties outside
standing among them. It seems not a little surprising
to see one person cutting through the space occupied by
another.
THE TANK.
An excellent and cheap tank (similar to the one shown
in Fig. 26), but with permanent clamps without screws,
is now shaped so as to slide into the Sciopticon stage
without drawing forward the extension front. As the
space at the top is unobstructed, all sorts of experiments
with it arc easily managed. Living creatures encaged
in it, in air or water, figure upon the screen in huge pro¬
portions, and with wonderful activity. Some fish and
parts of many insects are so transparent as to show in¬
ternal structure. Even opaque objects, when their out¬
lines are sharply focused, appear in relief unlike a mero
'hadow. With almost every object thus shown, except