• Wilson, J. M.: The Masterpieces of the Centennial International Exhibition, Vol. III: History, Mechanics, Science. Philadelphia (1876) S. 27 - 31
• The American Journal of Science and Arts, 8, 1871, S. 113 - 117 (vom Erfinder selbst)

Besonderheiten....:
Varianten.........:
Konstrukteur*.....: George Barnard Grant (1849-1917), s. a.  http://history-computer.com/Babbage/NextDifferentialEngines/Grant.html
Eine Übersicht zu seinen Maschinen gibt
Annual Record of Science and Industry for 1876. New York 1877, S. 43 / 44:
"CALCULATING MACHINES. Mr. George B. Grant, while a student of the Lawrence Scientific School, invented a new and simple form of calculating machine, which is now on exhibition in Machinery Hall, Philadelphia. Two styles are now made, the first being for special use, while the second is intended for use in counting houses, insurance offices, etc.

The Difference Engine. This is a large machine built for the University of Pennsylvania, and designed for the construction of large mathematical tables, such as tables of logarithms, sines, tangents, reciprocals, square and cube roots, etc. It computes the terms of any such table, and prepares a mould of them stamped in wax, from which an electrotyped plate is made, ready for the press. It stands five feet in height by eight in length, weighs 2000 lbs., contains, when in full working order, some 15,000 pieces, and is worth about $10,000.

The Calculating Machine is a smaller instrument for common operations in multiplication, division, etc. It is a foot in length by half as much in height and width, weighs twenty pounds, and contains less than 400 pieces, less than 75 of which are working parts. It takes numbers up to nine decimal places. Its mechanism is simple, strong, and durable; its manipulation is easy."

Designer..........: