Comptograph

After Dorr E Felt invented and began to sell successfully a key-driven adding machine known as the Comptometer, he designed a printing adding machine dubbed the Comptograph. This example has a cherrywood case and eight columns of metal key stems, with turquoise and white color-coded discs set in the metal key tops. Digits and complements of digits are shown on the discs. Each column has nine keys. The cover under the keys consists of metal slats with holes drilled in them, with one slat for each column of keys. A glass window at the front shows nine metal wheels that record totals.

On the right side toward the front are a knob and a lever. Depressing the lever allows one to turn the knob and zero the total. Immediately to the right of the keyboard is a small lever, which is pushed up to release the keys. Further to the right are two large buttons attached to levers. When the button at the right back is depressed, the carriage moves to a new column. The other button on the right may advance the paper. To the left at the front is another large button on a straight shaft (depressing this button probably is intended to print totals or subtotals). At the back of the machine is a wide carriage, the printing mechanism for the adding machine, and a ribbon. This mechanism prints eight-digit entries and totals. A bell on top of each of the spools for the ribbon rings to warn that the ribbon is almost unwound.

The machine is stamped on the front below the glass window: 1902. It is marked on a metal plate screwed to the right side: MODEL A No 1902 (/) PATENTED. It is also marked there: MAR. 11. 1902. It is also marked there: OTHER PATENTS PENDING. (/) COMPTOGRAPH CO. (/) CHICAGO, U.S.A.

The coloring of the keys resembles that on the Comptometer with catalog number MA.248688, which dates from 1898, and the Comptograph with typewriter MA.323636. The Accession Journal dates this machine to 1900, but the tag screwed to the machine indicates a slightly later date.

References:

Felt & Tarrant, Accession Journal, 1991.3107.06.

Pamphlet 1994.3060.05.

Currently not on view