Marchant Model B Pony Calculating Machine

This manually operated, lever-set and non-printing pinwheel calculating machine has a black steel housing and a wooden base. Nine levers rotate forward to set digits on the pinwheels, with color-coded digits marked on the spaces between the levers. A row of nine dials in back of the levers records the number entered. A bar in front of the levers can be raised to zero them, and a wing nut on the left side rotates to zero the entry register. The steel operating crank with its wood handle extends from the right side of the machine and rotates backward (clockwise) for addition and multiplication and forward (counterclockwise) for subtraction and division.

A movable carriage at the front has 18 windows that show dials of the result register on the right and ten windows for the revolution register on the left. The digits in the revolution register are white for additions and red for subtractions. Decimal markers slide above all three registers. A metal box at the front of the machine holds two bars, one for moving the carriage in either direction. Wing nuts at the ends of the carriage zero the registers on it. A bell is on the left side of the machine.

A metal tag to the left of the levers reads: The (/) Marchant (/) MANUFACTURED BY (/) MARCHANT CALCULATING (/) MACHINE CO., Inc. (/) OAKLAND, CAL. (/) PATENTED JUNE 6. 1911 (/) FEB. 22. 1916. A metal tag attached to the back reads: 81399. A mark on the back of the carriage to the left reads: A1216. A metal tag attached to the base reads: DONATED BY (/) BENHAM ENGINEERING COMPANY (/) CONSULTING ENGINEERS (/) OKLAHOMA CITY, OKLAHOMA (/) USED BY FOUNDER (/) COL. WEBSTER L. BENHAM (/) PAST NATIONAL DIRECTOR, ASCE

A layer of felt separates the machine and its wooden base. The base is not rectangular, but curved to follow the profile of the machine It has 3 rubber feet and fits inside a leather-covered, velvet-lined box.

This calculating machine was used by consulting engineer Webster Lance Benham (1882–1952), a veteran of the U.S. Army Corps of Engineers, in his work at Benham Engineering Company in Oklahoma City, Oklahoma. He founded that firm in 1909. The date of the machine is deduced from the serial number.

Compare to the Marchant Model A Pony (MA.311952), which only will calculate 13-digit products.

References:

J. H. McCarthy, The American Digest of Business Machines, Chicago: American Exchange Service, 1924, p. 549.

Accession file.

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