Fig. 47.
Fig. 48.
Fig. 49.
Second.—Put the sheets of cork in their places first, then make a few little slits through both metal and cork with the point of a penknife, and then bind the two together with a few ordinary paper fasteners. This arrangement is shown in section in [fig. 49].
Just one point more concerning the metal collecting box. You will often call moisture to your aid in keeping the butterflies flexible and soft. This will have but little action on zinc, but will sooner or later cause the 'tin' (really tinned iron) box to rust. Here, then, is a point in favour of zinc, but still a home-made 'tin' collector will last a long time if kept dry when not in use.