Kummer's ComputerCounting device
Designer: Ernst Eduard Kummer
Made in: Russian Empire (now Russia)
Dimensions: 85 × 5 × 125 mm
Weight: 600 g
Tags: russiamakes, polytech, рдс, россияделаетсама, политех
Registered in March 1847 as an "arithmetic device" by Heinrich Kummer, a music teacher from Saint-Petersburg. It consists of two metal 65 х 105 mm plates rigidly connected to each other at the edges. The numbers are entered by means of stylus and laths. They can be moved along the troughs. The device has two sides, one for addition and the other for subtraction.