Since the pin is pushed in to its full length, a blow cannot dislodge it. The spherical head in contact with the map gives a very neat appearance, yet the spherical shape permits the fingers to remove the pin by straight pulling without any difficulty whatever. The smooth needle-point of good quality steel does not rust easily and it does not cut the surface of the map. When a pin must be removed, the hole is so small that it is scarcely noticeable.

MAPS AND PINS

Pins having spherical glass heads may be used on wall maps without any danger of the heads fading from sunlight. The glass surface is so smooth that dust cannot collect sufficiently to affect the color appearance of the pin head. Even if the map does get dusty, it is perfectly safe to use the feather duster on a wall map having pins which are pushed in so far that the spherical heads are in contact with the map surface Dustmg of such a map ^MlI not loosen the pms ui any

Review of Reviews

Fig. 187. Location of the Plants Affiliated with the University of Cincinnati, College of Engineering. Every Star Represents a Plant Where Co-operative Engineering Students are Employed

A wall exhibit like this is easily made by using a red legal seal and red stars such as can be purchased at

many good stationery stores

way. A wall map on which pins with spherical glass heads are used can be very cheaply mounted, it needs no glass cover, and the pins can be put in or taken out instantly, thus giving a location record which is at all times in plain view, yet thoroughly accurate.