The adding device of Kummer

Several people experimented with versions of simple mechanical calculators, that involved strips of metal with numbers marked on them mounted in a frame, where a stylus was used to slide these strips up and down. A few names that usually rise to the top of the pile in this regard are Claude Perrault, who invented the first form of this class of devices (see Abaque Rhabdologique) sometime around 1670, and the Frenchman Caze, who created his version—nouvelle machine arithmétique around 1720. One problem with Caze’s machine was that it wasn’t possible to perform carries from one column to another. This issue was solved around 1845 by the Izrael Abraham Staffel (see calculating machines of Staffel) and by the teacher of music in St. Peterburg, Russia—Kummer.

Kummers’s adding device from 1846

Kummer was a teacher of music in a high school in St. Peterburg. In 1846 he presented to the Russian Academy of Sciences in St. Petersburg his adding device.

The main principle of the construction Kummer borrowed from Slominski's adding device, which have already been presented to the Russian Academy of Sciences in St. Peterburg. However this device that went down in history of computer facilities as Kummer's Addiing Machine, appeared to be considerably more effective, than the device made by Slominski. The reviewer on this device was the famous mathematician Ostrogradsky. In his review he noticed, that the main idea was borrowed from Slominski, but the construction resulted was incomparably simpler and more convenient in use. One of the major of advantages of Kummer's adding machine compared with Slominski's device was portability. Ostrogradsky noted that to a sheet of paper folded eight times, would be as thick as this device, but the length and the width will be much more. With smaller sizes it would be inconvenient to deal with it.

The numbers are entered by means of stylus and laths, which can be moved along the troughs. At the side of the laths the numbers from 0 to 9 are marked. The carrying is done by means of teeth. Each lath has a tooth, which can touch the similar tooth on the adjacent lath and to move it 1 position upwards or downwards, if it is necessary.

The adding device of Kummer is first device of this type, manufactured in quantity. Kummer received on 29th of March, 1847, a patent for his device for 10 years. The device was produced by the firm Mechaniker und Optiker I. E. Milk in Moscow in significant quantity and later on was serially released (with various modifications) up to the 70s of the 20th century. Some other devices of this type are examined in the section Gadgets of this site.

There is some kind of mystery about the personality of Kummer. Almost nothing is known about Kummer, the russian misuc teacher. I'd like to mention however only two interesting facts: First—the name of the one of the biggest german mathematicians of the XIX century is Ernst Eduard Kummer (1810-1893). Second—in 1869, some Henry Kummer from New York, USA, patented a calculator, which is absolutely identical to the device of Kummer, the music teacher in St. Peterburg (see the figure below). It seems Kummers was a very big and communicative family, wasn't it :-)

Henry Kummer's calculator from 1869