Dunbar's Patent Self-Adjusting Steam Piston Packing
- SIGNED
- Springfield, Massachusetts: Connecticut River Railroad Company, 1867
Springfield, Massachusetts: Connecticut River Railroad Company, 1867. Very good. Light toning, letter folds, a couple spots with worn envelope.. Illustrated 1867 circular with handwritten letter pitching a patented self-adjusting piston for steam engines to a prospective customer. The letter is signed on letterhead for J. Mulligan, Master Mechanic at the Connecticut River Railroad Company. The letter notes the enclosed circular, which offers testimonials and pitches the product as an alternative to clunkier mechanism without a spring self adjusting. With original 3.25" by 5.5" envelope hand-addressed to O.S. Douglas Esq. of Thompsonville, Connecticut. Circular measures 9.75" by 7.75", letter measures 8.5" by 5.25