Section of a Comptometer by Felt & Tarrant showing mechanism
1908-1909
Section showing construction of Burroughs hand operated adding and calculating machine (non-listing) class 5
1929
Cut-away demonstration model of Walther WSR 160 calculating machine
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
Stripped model of a "Curta" pocket calculating machine with cylindrical metal case
1950-1951
Working model of a Leibniz stepped reckoner
1937
Working demonstration of barrel calculating machine mechanism
1978-1980