Page:Library Construction, Architecture, Fittings, and Furniture.djvu/75

Rh If any of the bookcases are exposed, and have doors, provision must be made for ventilation; this is best done by inserting wire netting in the panels instead of glass or wood.

The method of construction of a bookcase of wood, with fixed shelves, is too well known to need description. There are several appliances in use for allowing the shelves to be easily and readily moved. One of these is that shown in Fig. 8, and is known as "Tonks' Fittings." A groove is run at the back and front of each upright, and in this is screwed a strip of metal, perforated with oblong holes ¾ of an inch apart. A small square catch, with a piece projecting, is slipped into a hole, and stands out at right angles to receive the shelf, which rests upon four of these, placed one in each upright strip. This fitting allows the shelf to be raised or lowered at distances corresponding to the perforations in the uprights. In fitting, it is important to cut the grooves in the uprights deep enough to embed the whole of the iron strip; if not, it will project and damage the bindings.