Moritz Hermann von Jacobi

Photo: Collections of the University of Tartu Library

Physicist, Electrical Engineer and Architect Moritz Hermann von Jacobi

21 September 1801, Potsdam – 10 March 1874, St. Petersburg

Jacobi was born into a rich Jewish family. His father was a personal banker of King Frederick William III of Prussia. Moritz Hermann studied engineering at Berlin and Göttingen universities. In 1834, he moved to Königsberg where his brother Carl was a professor of mathematics. There Jacobi invented his first originally designed electric motor.

In 1835–1840, he was the Professor of Engineering at the University of Tartu and in 1835–1837 also the university architect. In the cityscape of Tartu, he could be remembered by Angel's Bridge, which got its present design in 1836 according to Jacob's project. In 1837, he invented electroplating, a technology widely used to coat objects with a thin (precious) metal layer.

Jacobi left Tartu for St. Petersburg, where he became an academician in 1839. Together with Emil Lenz from the University of Tartu, they studied electromagnetism and launched the theory of electromagnetic machines. On 13 September 1838, an electric motor-driven boat designed by Jacobi was tested on the Neva River, capable of carrying 14 passengers upstream for 7.5 km (about 5 km per hour). This was the first time that an electric motor did useful work. The power source used was a voltaic pile invented by Georges Frédéric Parrot.

In 1842–1845, Jacobi built an electric telegraph line between St. Petersburg and Tsarskoye Selo. He designed several different telegraphs, including one that printed letters. Some of his inventions were widely used in the military e.g., the self-exploding mines invented by Jacobi were used to protect Kronstadt in the Crimean War (1853–1856). In addition, he initiated electrical engineering education in Russian army.

Acknowledgments

1847 Full Member of the Saint Petersburg Academy of Sciences

1853 Member of the Lincean Academy in Rome

1859 Corresponding Member of the Royal Prussian Academy of Sciences

1864 Corresponding Member of the Göttingen Academy of Sciences