This section is from the book "Cassell's Cyclopaedia Of Mechanics", by Paul N. Hasluck. Also available from Amazon: Cassell's Cyclopaedia Of Mechanics.
Fig. 1 is a section through a window board for flowerpots showing how it is fixed with brackets and screws to the sash frame.
The board can be kept level with two or three pieces of l 1/2-in. or 2-in. wood cut wedge-shape to the splay of the sill, and the outer end can be fitted over the siil and the end shaped as shown at A; this will improve the appearance. The board should be about 1 in. thick, and may be of any width from 6 in. to 11 in. It should be cut round to fit the brickwork and just overhang the stone sill, as shown at Fig. 2; the bracket pieces should be nailed to the board underneath. A strip of moulding nailed round the edge, so as to project as shown, will prevent the flower pots slipping off.

Fig. 1.

Fig. 2. Window Board for Flower Pots.
 
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