But I must have done with moralising and proceed to business. The question is--How shall we set to work about the construction of a collecting box? If it is to be a wooden one, select or make a box of such a size as to suit your pocket or satchel, and cover the bottom, and lid too if the depth allows of it, with sheet cork or slices of good wine corks, about one-eighth of an inch thick, fixed on with glue. The metal box is not quite so easy, but even here you may save yourself much work by keeping your eyes open. Very neat little collecting boxes can be made out of the flat metal boxes in which are sold certain favourite brands of tobacco. Some of these are just the right depth, and also of a very convenient size for the coat pocket. Beg one of these boxes from a smoking friend, and if the lid is not held by a hinge (a great advantage, by the way), you can easily solder on a brass one. All that remains now is the fixing of the cork. Buy a sheet of cork at a naturalist's shop, this being a commodity always in stock, and cut out two pieces just the size to cover the bottom and the lid. Gum and glue are not very satisfactory as fixing agents, for, as you will presently learn, there are times when it will be necessary to keep the box moist, and moisture softens both these substances. The cork must be fixed by means of little strips of metal. Here are two ways of doing this: First.--Cut a few little strips of sheet tin, each about two inches long and one-eighth wide. Double and bend them as shown in fig. 46, and solder them to the surfaces which the cork is to cover (fig. 47). As the cork is pushed in its place, these little slips are allowed to force themselves through slits in it made by means of a penknife, and then the ends are bent over as shown in fig. 48. Two or three such fasteners will be quite sufficient to hold down each sheet of cork. [Illustration: FIG. 46.] [Illustration: FIG. 47.] [Illustration: FIG. 48.] [Illustration: 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.