John Ballou's Adding Machine
On March 13, 1860, a certain John Ballou of Cincinnati, Ohio, took out a US patent №27418, for a calculator. It seems the device never went into production and only the patent model survived to the present, kept in National Museum of American History, Washington (see the lower image).
The inventor of this small and curious calculator was a remarkable man—John Ballou Newbrough (1828–1891), who during 1840s and 1850s studied and lived in Cincinnati. John Ballou (see biography of John Ballou Newbrough) was called by some people America's Greatest Prophet. It was claimed that, he could paint in total darkness with both hands at once; that by closing his eyes, he could read printed pages of any book in any library; that he could bring back recollections of astral travels (or astral projections); that under control he could lift enormous weight, even a ton, without apparent effort. It must had been as easy as winking for such a powerful mind to devise this rather curious calculating instrument in the late 1850s (actually, there are two other US patents (№21621 from 1858 and №24481 from 1859) for simple calculators, granted to John B. Newbrough of St. Louis.)
The Ballou's Calculator (© National Museum of American History, Washington)
The calculator of Ballou was a small metal and wood adding machine, with measurements: 10 cm x 11.5 cm x 13.9 cm. It was somewhat similar to the Jabez Burns' addometer, patented at the same time.
The lever-set adding device has a metal casing, painted black and a wooden bottom. The curved front of the machine has slots for six movable wheels, the right-hand wheel operated for units, the next for tens, etc. The part of the case to the right of each ring is marked with the digits from 0 at the bottom of the curve to 9 at the top. A crosswise shaft in the machine carries a series of six toothed metal rings that fit between the openings in the case and serve as finger wheels, ratchets, and registers. The digits are inscribed around their edges of the rings, next to the teeth. One digit of each wheel is visible at the top of the machine, showing the result when numbers are entered by turning rings forward.
A tens carry mechanism is also provided—the left side of each ring has a pin (a shifter) every ten places, which drives the adjacent wheel when carrying is required.