Boris Semenovich Iakobi

(also, Moritz Hermann von Jacobi). Born Sept. 21, 1801, in Potsdam; died Mar. 11, 1874, in St. Petersburg. Russian physicist and inventor in the field of electrical engineering. Academician of the St. Petersburg Academy of Sciences (1847; corresponding member, 1838).

Iakobi studied at the universities of Berlin and Göttingen. He received an architectural degree in 1829; he then worked as an architect before moving in 1834 to Königsberg, where he turned his attention to electrical engineering. He studied electromagnetism and constructed an electric motor with a commutator of original design.

In 1837, Iakobi became a Russian citizen and moved to St. Petersburg, where he continued working on the practical applications of electricity, chiefly for military purposes, as well as in transportation. He designed several electric motors, one of which operated on a primary cell battery and was installed on a ship that navigated the Neva River in 1838. In 1850 he published the article “On the Theory of Electromagnetic Machines,” which proved to be the first attempt to analyze scientifically the operation of an electric motor. He worked together with H. F. E. Lenz in research on electromagnets and proposed a method of designing them (1838–44).

Iakobi conducted research in telegraphy. He designed about ten types of telegraphs, including the first letter-printing telegraph (1850), the Iakobi telegraph. He directed the laying of the first telegraph lines in St. Petersburg and between St. Petersburg and Tsarskoe Selo (1841–43). He also studied the development of primary cell batteries and designed new types of mine weapons, including self-igniting electrocontact mines and mines detonated by an induction mechanism; he helped organize “galvanic teams” in sapper units of the Russian Army. One of Iakobi’s most important contributions was the study of processes of electroplating technology, which he first reported to the St. Petersburg Academy of Sciences in 1838; Iakobi published a complete description of these processes in 1840.

Iakobi carried.out important research in electrical measurements. He proposed a number of original designs of rheostats and several new electrical measuring instruments and developed, together with Lenz, the ballistic method of electrical measurements. His work contributed to the more rapid solution of many problems in metrology, for example, to the establishment of the metric system, development of standards, and selection of units of measurement.