Contrive a six-sided box, six inches in diameter and ten deep, lined
with tin or other polished surface, and with a double convex lens in the
centre of one side. On the opposite side, exactly in its middle, cut out
a hole to receive the face of a watch, with a little shelf outside to
hold the case firmly.
Support the box in the centre on a hollow leg, which is watertight and
is filled with water, to float a night-light, and let the leg fit into a
stand to go on a table by the bed-side or on a shelf at the foot of the
bed.
_Action._—The lens will magnify the reflection of the watchface so that
the figures can be clearly distinguished.