STERN, Abraham Jakub
* 1769, Grubeschow, Poland
† 2. 2. 1842, Warsaw, Poland
inventor, mechanic
S. was the son of a poor Jewish family. He was trained to be a watchmaker in his hometown. There Stanisław →Staszic, who bought lands in Hrubieszów, noticed his talent and enabled him to move to Warsaw.
Many of his inventions and constructions were from the field of measurement and numbering. His first invention was a kind of distance meter with two target devices. It was used by engineers, as well as the army, and was to replace Marinoni's measurement board. In 1821, he also manufactured a vehicle that noted down the position and outline of the terrain, as well as its topography, while still preserving the scale. For the field of agriculture he manufactured models of a lather, saw and a corn mill, which exploited the power of horses. In 1835, he presented a device for preventing injuries to horses, people, and vehicles.
His most important inventions are various calculating machines. The first calculating machine, manufactured in 1812, performed four basic calculating functions. In 1817, he improved the calculating machine with two additional functions: exponentiation and root extraction. A year earlier, during the visit of Czar Alexander I in Warsaw, he was able to present his device.
S. published reports on his inventions in the chronicles of the Society of Friends of Science. By the order of the society, he also evaluated the projects and inventions invested in, and conducted tests on hardening metals. When the rabbinical school was founded in Warsaw in 1818, S. compiled the curriculum and became its first headmaster. He was also a writer and translator of Hebrew literature.
