On 18 February 1881, Hugues Beaucourt (1845-1919), a son of the famous organ-builder from Lyon, France—Hippolyte-César Beaucourt (1822-1888), patented (French patent 141208) appareil pour calculer, an interesting adding device with rotatable (similar to telephone number dial) input mechanism. Later in the same 1881 he got a Spanish patent (Pat. Nr. ES1709A1 for aparato para calcular) for the device.
Hugues Beaucourt succeeded his father’s trade of organ making (from 1869 until 1914 he was in charge for the family business), but obviously had an inventive mind, because he was a holder of quite a few patents in different countries for various devices like: device for sounding motor-car, automatic adder for the demonstration of arithmetic principles, etc.
The original adding device of Hugues Beaucourt never went into production, but it was re-patented some 30 years later by his son Edmond Beaucourt (b. 1878) (Swiss patent CH62168 from 1912 for Machine à calculer portative, and Great Britain patent GB191217401 from 1913 for Improved Adding and Subtracting Apparatus) and was manufactured and sold under the name Le Recta in 1910s (see the nearby photo).
Le Recta is a RECTAngular metal column adder with dimensions (LxWxH): 12.5 x 8.5 x 1.5 cm, and weight: 524 g.
The construction of the device (see the nearby patent drawing) is simple and reliable, although the intriguing dialing input mechanism must had been rather slow (but also not prone to the common problem of the exceeding momentum, that could be given in an adding action).
The device can be used for adding and subtracting and comprises of a primary disk or wheel and one or more secondary numerical disks (in the patent application there three disks in the result mechanism), one of which will be turned through a predetermined angle at each revolution of the primary disk and will on completing each revolution turn the next secondary disk, thereby indicating the figures units, tens, hundreds, etc., appearing through orifices in the casing which is in the form of a small box.