In the second half of the 19th century, several American inventors proposed adding machines operated by moving levers, rotating discs or turning screws with the fingers. At the time, they were required to submit models of their inventions to the U.S. Patent Office. Some of these models survive in the collections shown here. At least one of them, the Lang Sales Register, apparently was manufactured.
Several of these inventors took out other patents for other inventions. The most notable was Frank S. Baldwin, who invented a pinwheel calculating machine and whose ideas were the foundation of the products of the Monroe Calculating Machine Company.
Perhaps the most successful finger-operated machines were those made by the Adding Machine Division of the American Can Company of Chicago, beginning in 1914. Even this product was not entirely successful – in 1922, the printing version of the machine was discontinued and manufacture switched to the American Adding Machine Company, also of Chicago.
