The instrument shown in the cut is the invention of Mr. Maginnis, and is designed for producing equidistant hatchings. It consists of a short ruler, A, and a triangle, B, supposed to be one of 45°, but which may be of any angle. The triangle carries two stops, c c, while the ruler is provided with a conical piece, D, which is slotted, and is held by a screw. The play that occurs between this conical slide and the stops varies according to the position of the former.
RULER AND TRIANGLE FOR HATCHING.
The apparatus operates as follows: In the figure, the stop to the right being in contact with the piece, D, a line is drawn along the right side of the triangle. Then the ruler is made to slide along the triangle until D touches the other stop, and then the triangle is slid along the ruler until the stop to the right touches D again. In this position another line is drawn, and so on. The position of the piece, D, between the stops is regulated according to the fineness of the hatching to be done. - Chronique Industrielle.