Hugues and Edmond Beaucourt
On 18 February, 1881, Hugues Beaucourt (1845-1919), a son of the famous organ-builder from Lyon—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. 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 at least one more patent (for device for sounding motor-car).
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 lower photo).
Le Recta calculating machine of Beaucourt
It was a 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 lower 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).
Le Recta calculating machine (patent drawing)