Stanhope's calculating machine, 1777.

Calculating machine, made by James Bullock, in a metal case, invented by Charles Stanhope, 3rd Earl (1753-1816), in 1777. Stanhope was an English politician and scientist who is known for his inventions in printing, including an iron pres and stereotyping, a proces for moulding and reproducing forms. The calculator was the first to tackle the tens carry mechanism.