with a cloth tape as suggested for straw-board mounts, or the whole built up combination may be framed with picture framing but without using any glass covering. The cork composition used should be Vs-inch thick. Maps backed with cork composition and used with glass-head pins having needle points will permit almost unlimited puncturing from frequently moved pins. If the map is mounted on cork composition the sharp-pointed pins are easily pushed in and removed, yet the record is always accurate because the pins cannot be knocked out.

Numerous wall maps can be very conveniently used if they are mounted on vertical swinging-leaf display fixtures similar to those shown in Fig. 219. The two surfaces of each swinging leaf should be covered with corrugated straw-board and muslin, or preferably with cork composition in order to get a good surface into which to insert the pins. As adjacent leaves are likely to strike and break the glass heads of the pins, projecting bumpers should be placed on every other leaf to allow enovigh clearance for opposite pins when the leaves come in contact. The rubber-covered bumpers used to prevent door

234 GRAPHIC METHODS

knobs from striking plastered walls can be placed at the top or bottom of alternate leaf surfaces. If these rubber bumpers are not available, a narrow strip of wood at the top and bottom of each leaf will serve.

When employed with glass-head pins having needle points, the drawer cabinets for maps used to route salesman, etc., can have a layer of cork composition fastened in the bottom of each drawer. The maps are then glued to the surface of the cork composition. The drawer cabinets regularly found on the market have sufficient drawer depth to permit placing a ^^g-inch layer of cork composition in the bottom of each of the regular drawers and still allow room for the pins.