Among the numerous arrangements that have been devised for drawing circles in diagrams, sketches, etc., one of the simplest is doubtless that which is represented in the accompanying figure, and which is known in England as the "scholar's compasses." It consists of a socket into which slides a pencil by hard friction, and to which is hinged a tapering, pointed leg. This latter and the pencil are held at the proper distance apart by means of a slotted strip of metal and a binding screw. When the instrument is closed, as shown in the figure to the left, it takes up but little space, and may be easily carried in the pocket without the point tearing the clothing, as the binding screw holds the leg firmly against the pencil.
The mode of using the apparatus is so well shown in the figure to the right that it is unnecessary to enter into any explanation. - La Nature.
THE SCHOLAR'S COMPASSES.