Acknowledgement to my correspondent Mr. Silvio Hénin, Milan, Italy, for his pioneering work on Guinigi’s calculating machine.
In the 1850s (or even earlier) Count Niccola Guinigi-Magrini, a nobleman from Lucca, Italy, designed and made a simple dial adder (which he called Manipolatore Aritmetico—Arithmetical Manipulator) with a unique design that summed eight-digit figures up to 99,999,999. Now the only surviving device is exposed in Arithmeum Museum, Bonn, Germany (see the lower images). Arithmeum recently uploaded a 3D animated video made by a student of Computer Science, showing the functionality of the machine in detail and also giving an impression of its operation and aesthetics (see the Arithmeum video)
On the lid of the device is attached an engraved brass plate with the inscription N. GUINIGI Invento ed Eseguı 1858 (N. Guinigi Invented and Built in 1858). Guinigi even asserted that he have used his Manipolatore for 19 years while performing the duty of some administration task in the town council of Capannori, near Lucca. So probably his device had been designed much earlier than 1858.
The calculating machine of Guinigi was presented in the newspaper Monitore Toscano, published in Florence on 10 February 1859. There is also a letter from Tito Gonnella (another Italian inventor of calculating machines), to Filippo Corridi, president of the Tuscan Academy of Arts and Manufacturing (Accademia Toscana di Arti e Manifatture), dated 26 February 1859, in which Gonnella complained that the academy had ignored two calculators he invented and built between 1857 and 1859, but acknowledged the arithmetical machine of Guinigi.
Together with the machine of Guinigi was preserved a seven-page manuscript, handwritten by the inventor himself, entitled Manipolatore Aritmetico, which describes the calculator in detail and explains how to use it, with practical examples. The manuscript states: The purpose of this small machine is to perform additions, driving them to an easy game for everybody, doing away with computing and carrying, always to a correct outcome. The user does not need more knowledge than just [reading] numbers. A quarter of an hour suffices to master the machine operation.
On 6 December 1858, Guinigi submitted the prototype of his calculator to the Accademia Toscana. The device was examined by a commission of two mathematicians, Antonio Ferrucci and Giovanni Novi, who wrote a report, which concludes: this [machine] is particularly worth mentioning for its simplicity and the solidity of its organs… with no essential fault… [but] presents some flaws in its construction…. The report was presented by Ferrucci during the Ordinary Meeting of the Academy on 16 January 1859 and recommended the inventor to introduce some improvements in the construction.
Guinigi’s adder is mounted in a wooden box (dimensions: 37 x 38 x 18 cm, weight: 9 kg) with a large circular dial on the top. Inside the large dial is a glass plate covering eight small, round windows showing eight digital wheels. The gears, levers, axles, and cams were made mostly of boxwood, but an internal brass slab that holds the accumulator and carries axles and other small elements (screws, pins, and springs) are made of brass or steel.
The large dial has 20 knobs on its circumference, featuring the numbers 1 to 20 inscribed on an internal circle. The dial can be rotated clockwise by the knobs until a stop is reached (just like a rotary telephone dial). On the front side, eight levers (numbered 1 to 8) stick out; each one can be pressed down, but an internal device prevents pressing more than one at a time.
The mode of operation of the machine described by Guinigi in his manuscript seems really easy: having a vertical list of numbers to sum, the addition is made by columns, starting on the right, like accountants do with pen and paper. The rightmost front lever is pressed and each digit of the units column is entered in succession by pressing the respective knob on the dial wheel and turning it clockwise until the stop is reached (zeros are ignored).
Tens carries are automatically added to the next decimal order. Then the rightmost lever is raised and the one to its left pressed; the tens column digits are entered as before. The procedure is then repeated for all the columns and the result can be read in the small windows under the glass cover.
Guinigi obviously realized that his machine is subject to jamming when a ripple-carry occurs (as was the case with most previous and coeval calculators) for example, when adding 1 to 99999. The two brass buttons on the front side are designated as anti-jamming devices, one for the lower four decimal orders, and another for the higher ones (the buttons are connected with two levers operating on the carry gears, giving them an extra hit in case of ripple-carry). The machine also lacks (again as most calculators of the time), a device of critical importance—for zeroing. To reset the counter wheels, the operator must add the complement to 10 to each accumulator, starting with the rightmost one.
The making of Guinigi’s adder is all in wood with small metal details (springs and screws), but the inventor wrote in his manuscript, that intended to make [the machine] again, in metal and more precise, but both for lack of will and for shortage of time… making it in metal with a new design remained, and I think will remain forever, just a wish. So obviously the above-mentioned device remained only as a prototype and was not developed further and popularized.
Biography of Niccola Guinigi
Count Niccola Guinigi-Magrini (also spelled Nicola or Nicolao) was born in 1818 in Lucca, a Bourbon-Parma duchy in Tuscany, Central Italy. He was one of the last descendants of two outstanding Lucchese families of wealthy and powerful merchants, Guinigi and Magrini, who formed the Guinigi-Magrini branch at the beginning of the 17th century. Guinigi’s most renowned ancestors were Francesco Guinigi (ar. 1320-1384), who orchestrated the purchase of Lucca’s independence in 1369 and was rewarded with the honorific Padre della Patria, and his youngest son Paolo Guinigi (1372-1432), who ruled Lucca (titled Capitano e Difensore del Popolo—Leader and Defender of People) from 1400 until 1430.
Niccola Guinigi was part of the local aristocracy, a man of liberal mind and progressive ideas, and an active partaker in the public life of Lucca. He was a member of the Organizing Committee of the fifth Meeting of Italian Scientists in 1843 and also a representative to the Paris Exposition Universelle of 1855 and the Dublin International Exhibition of 1865.
In May 1848, Guinigi fought in the battle of Curtatone against the Austrian imperial forces. In 1849, while serving in the Lucca’s Civil Guard (he was an officer and a head of the Civil Guard), was taken prisoner by rioters and sentenced to death, but eventually escaped the execution. Later on, Guinigi held public positions in Lucca, as chairman of the Royal Commission for the Conservation of Fine Arts and Encouragement of Arts and Manufactures and president of the Departmental Council.
Count Niccola Guinigi died on 25 January 1900, leaving no issue.
Literature: Silvio Hénin, Massimo Temporelli, An Original Italian Dial Adder Rediscovered, IEEE Annals of the History of Computing, 2012, vol. 34, n. 2