Patent Model for Rule Invented by Henry Adler

Adler, Henry · 1878

Henry Adler received U.S. Patent 206,410 for a combination rule, paper tearer, pencil sharpener, and T-square on July 30, 1878. The model he submitted with his patent application is a hollow sheet metal triangular tube, with a cone for sharpening a pencil at one end and a wooden stopper at the other. The stopper is supposed to have an eraser at one end, a sharpener for slate pencils at the other end, and be removable so that pens and pencils may be stored within the tube. However, at present the stopper cannot be removed from the instrument.