DEMONSTRATIONS IN PHYSICS
22»
fig. 109, or two small glass plates inclined together and also
fitted at the top in a strip of wood (fig. 110), in a small tank of
water placed on the lantern stage. The tank may be of any
Fig. 109
Fig. 110
convenient shape, and the simple form shown in fig. Ill,
where the glass plates are mounted in a wooden frame to fit
the usual slide-stage, will answer perfectly well. The reverse
Fig. Ill Fro. 112
phenomena shown between glass and such a fluid as mercury,
are projected by a small apparatus like fig. 112, about double
the size there shown.