Comptometer Adding Machine, 1951

Mechanical adding machines like this Comptometer were indispensible--and almost indestructable--office equipment until the computer era. Dorr Felt's 1884 invention of a key-driven mechanical adding machine had become big business by the 1950s, when this Comptometer was made. This particular Comptometer was used in the accounting department of an eyewear manufacturing company from 1951-1967, when its operator retired.