Grant Grasshopper Calculating Machine

This is the form of calculating machine exhibited by George B. Grant at the Columbian Exposition held in Chicago in 1893. It is a lever-set non-printing manually operated connection pawl machine. The form is called Grant’s grasshopper model because of its appearance.

The machine has an open iron frame painted black, with steel and brass parts and paper labels. Five sliding pins at the front of the machine are used to set numbers on racks beneath. Next to each pin is a thin strip of paper with the digits from 0 to 9 printed on it. The digits increase as one goes toward the back of the machine. Each strip also has complementary digits in smaller type, for use in subtraction and division. Moving back a pin drives back a toothed rack.

Behind the racks is a movable carriage with 11 gears on it. A paper strip with digits on it is next to each gear. Turning a crank at the front right of the machine moves the racks back to engage the gears, turning each one of them in proportion to the number set. When the adding frame reaches the end of its backward movement, a cam set on the crank shaft at the front raises all the register gears a little so that the gears are disengaged from the racks and not moved in the return motion. One tooth on each gear extends so that when the gear has made a complete rotation, it engages one of the carry teeth arranged on a spiral shaft above the carriage. As the adding racks return to position, the shaft revolves and the carry tooth pushes the next gear up by one, resulting in a carry. The result appears o the paper strips between the gears on the carriage.

Releasing the carriage and turning it one revolution zeros the result shaft.

A slip of paper to the right of the number levers reads: GEORGE B. GRANT, (/) LEXINGTON, MASS. It also reads: 1.95. Y.

This machine was given to the museum by George B. Grant’s half-brother, Edwin A. Bayley.

Compare MA.310647 and MA.335633. MA.310647 has a metal plate at the back not found on MA.335633.

Currently not on view