276, _a_, the shelf can be secured firmly to the back, since there is side grain in which to drive nails or screws.

As to the direction of the grain of the support and the back, this should run in the direction of the largest dimension of each.

Where the back is long horizontally, for security in hanging, it is better to have two supports.[10] [Footnote 10: See the School Arts Book for Nov., 1906, "Design in the Woodworking Class," by Anna and William Noyes.] [Illustration: Fig.276.Wall Brackets, Double-Hung: _a_.

Single Support._b_.Double Support.] _Wall book-shelves_, Fig.

277, _plate-racks_, etc., are simply compound brackets.