A lengthy and confidential Autograph Letter Signed [to Leone Levi, the statistician], seeking Levi’s views on the British Government’s position on the establishment of the Committee of weights and measures led by Jacobi, and clarifying various issues concerning the metric system. In French. 3 pp. 10 x 8 inches, two clean tears neatly repaired, slight toning but generally good. Paris, 27 May 1867. Moritz Hermann (Boris Semyonovich) von Jacobi (1801 – 1874), Russo-German engineer and physicist born in Potsdam. Jacobi worked mainly in Russia. He furthered progress in galvanoplastics, electric motors, and wire telegraphy. He developed the maximum power theorem known as Jacobi’s Law. In 1838, he discovered galvanoplastics, or electrotyping, a method of making printing plates by electroplating. The stereotype was an impression taken from a form of movable lead type and used for printing instead of the original type. This technique is used in relief printing. He also worked on the development of the electric telegraph. In 1842-1845 he built a telegraph line between Saint Petersburg and Tsarskoe Selo using an underground cable. In 1867 he was a Russian delegate to the Commission on measurement units at the Paris World’s Fair. He was a strong proponent of the metric system.