Fig. 99.
A Pin-hole Camera is another extremely simple yet extraordinarily interesting contrivance (Fig. 100).
Fig. 100.
For this you require two mantle cases, one just large enough to slide easily into the other. Take the smaller one, and cover one end with tissue paper. This must be done neatly and strongly, otherwise, as the case slides up and down in the outer one, the tissue will tear. You should draw out on the tissue a circle just as large as the end of the case, and then all round, draw and cut little pointed tags to lap over the edges and stick down (Fig. 101).
Fig. 101.
One end of the outer case should be covered with thick brown paper in just the same way, and a tiny pin hole pricked exactly in the centre of the brown-paper end.
Now if a lighted candle be placed near to the pin hole, and if the inner case be moved to and fro till the right spot is found, an exact picture of the candle flame will be seen on the tissue paper.