Choice of lumber must be determined partly by the viewpoint of the adult concerned, largely by the laboratory budget, and finally by the supply locally available. Excellent results have sometimes been achieved where only boxes from the grocery and left-over pieces from the carpenter shop have been provided. Such rough lumber affords good experience in manipulation, and its use may help to establish habits of adapting materials as we find them to the purposes we have in hand. This is the natural attack of childhood, and it should be fostered, for children can lose it and come to feel that specially prepared materials are essential, and a consequent limitation to ingenuity and initiative can thus be established.
On the other hand, some projects and certain stages of experience are best served by a supply of good regulation stock. Boards of soft pine, white wood, bass wood, or cypress in thicknesses of ¼", 3/8", ½" and 7/8" are especially well adapted for children's work, and "stock strips" ¼" and ½" thick and 2" and 3" wide lend themselves to many purposes.
TOYS
The proper basis of selection for toys is their efficiency as toys, that is: