A ROSEWOOD INFILL TRY SQUARE by Darling & Schwartz, Bangor, Maine. This example of the October 6, 1857 U.S. Patent of Samuel Darling has a 12" length blade and it is clearly marked with the "D. & S." name and patent date as well as the U.S. Patent Date.. Length = 13.88 Inches (Ref. Id No.: 475205) [Free Shipping]