Section of a Comptometer by Felt & Tarrant showing mechanism

1908-1909

Cut-away demonstration model of Walther WSR 160 calculating machine

Section showing construction of Burroughs hand operated adding and calculating machine (non-listing) class 5

1929

Section of model "F" controlled-key Comptometer by Felt and Tarrant Manufacturing Co.

1921

Glass encased sectional model of Comptometer by Felt & Tarrant

1927-1928

Section showing construction of the earlier hand operated model of Burroughs adding and calculating machines

1929

Small trial piece for calculating machine invented by Charles Stanhope in 1777 with case

1777

Working demonstration of barrel calculating machine mechanism

1978-1980

Stripped model of a "Curta" pocket calculating machine with cylindrical metal case

1950-1951

Working model of a Leibniz stepped reckoner

1937