277.
In the latter case the back strip may have a short barefaced blind tenon which is mortised into the upright, Fig.278.It also fits into a rabbet on the upper back side of the shelf.

Made in this way the shelves can be knocked down easily.
[Illustration: Fig.277.Wall Book-Case.] [Illustration: Fig.278.Construction of a Knock-Down Book-Shelf Seen From the Back.] _Foot Stool or Cricket_, Fig.279.The grain of the supports should run up and down, because pieces with the grain horizontal would be likely to break under pressure.

Braces or a rail give additional support.

The top should not be larger than the base of the legs; otherwise a person standing carelessly on the stool is in danger of being upset.
[Illustration: Fig.279.

Cricket.] _A Drawing-Board_ is made up of narrow boards, with glued joints, with the boards so laid that the annual rings will alternate in direction, Fig.