No doubt, there are many celebrities, mentioned in our humble site as inventors of calculating devices, let’s make mention only Leonardo Da Vinci, Blaise Pascal, Gottfried Leibniz, and other not-so illustrious men. It’s time now to tell the story of Karl Wilhelm Otto Lilienthal, the famous German pioneer of aviation, known as the Glider King, as he was the first person to make well-documented, repeated, successful flights with gliders.
Otto Lilienthal (1848-1896) was a holder of more than 25 patents in Germany, the USA, Austria, and Britain. Interestingly, only four of them relate to his passion—the flying machines (actually some refer to inventions by Otto’s brother Gustav, but are patented in Otto’s name). The rest being given (the first patent was from 1875 for calorimotorishe maschine) for, among other things, games, mining machine, boilers, steam engines, and a calculating device (rechenapparat).
Otto Lilienthal was a mechanical engineer by trade, who in 1883 established his own mechanical engineering company for boilers and steam engines in Berlin. The patent for the calculating device (Patent №44632, 08.04.1888) was probably driven by the needs of his workshop and can be used primarily for multiplying numbers.
The simple calculating device of Otto Lilienthal (see the nearby patent drawings) is of the type Multiplizierscheibe (Multiplier Disc) and consists of two rotatable discs E and F, between the cover plate C and the bottom-plate D. The upper disc E contains a number of windows (openings) with the adjacent multiplicands, which are visible through the window L of the cover plate C. The lower disc F contains the multiplicands situated in such a way that, when a multiplier is visible through one of the holes of the disk E, the corresponding product appears just below the window K, provided in the upper part of the common cover plane C. There is a disk H for the insulation of the two discs against each other.