KRAVETS, TORICHAN PAVLOVICH

(b. Volkovo, Tula guberniia [now oblast], Russia, 22 March 1876; d. Leningrad, U.S.S.R., 21 May 1955)

physics.

Kravets’ parents, Pavel Naumovich Kravets and Felicitiana Karpovna Shagina, were physicians. In 1894 he graduated with a medal from the Tula gymnasium, where he received an excellent education that included both ancient and Western languages. (The knowledge of Latin was of great benefit for his future work in history of science.) In 1897 Kravets entered the mathematics section of the Faculty of Mathematics and physics at Moscow University; he graduated in 1989 with a first-class diploma. While Kravets was at the university. the Moscow school of physics headed by P. N. Lebedev was at its height. In 1907 he married Ekaterina Mikhailovna Svechina; they had no children.

Kravets’scientific activity was conducted in Moscow (1898–1914), Kharkov (1914–1923), Irkutsk (1923–1926), and Leningrad (1926–1955). In Lebedev’s Moscow laboratory. Kravets began work on the spectroscopy of colored solutions. The results were summed up in his M. Sc. thesis, “Absorbtsiia sveta v rastvorakh okrashennikh veshchestv” (Absorption of light in solutions of colored substances), defended at st. Petersburg in 1913. This work was both of purely scientific importance(the analysis of interaction of electromagnetic waves in a medium within a broad range of wavelengths) and of applied interest, for it made clear the possibility of chemical analysis of substances by means of absorption of electromagnetic waves. The “Kravets absorption integral,” introduced in this work (and since then included in modern physics dictionaries), enables one to determine the charge and mass of an equivalent oscillator corresponding to the given line or band of absorption from the analysis of absorption spectra. This work has become especially important with the appearance of dye lasers.

During his three years in Irkutsk, Kravets worked on problems in geophysics, investigating seiches of Lake Baikal. At approximately the same time these problems interested I.V. Kurchatov, who studied seiches in the Azov and Black seas). Theseiches are free oscillations of the water level in closed (natural or artificial)basins that may influence seismographic readings. Kravets was commissioned to set the work of the Irkutsk seismic station in motion.

In the course of doing so, he developed a model of the free oscillations of the basin that agreed to within i percent with the actual process. These investigations were continued at Leningrad in the late 1920’s, this time for the Baltic.

The main area of Kravets’ physical research in Leningrad was the physics of photographic images. To this end Kravets established a special department of scientific photography at the Vavilov State Optical Institute. he was first of all interested in the problem of latent photographic images, which had attracted the attention of D.F.J. Arago, Kravets also studied absorption of light by haloid silver salts. His interest in Lebedev’s laboratory. In the course of research on the physics of latent images, a group of kravets’ pupils and colleagues was formed; this group carried out investigations on applied photography and photographic sensitometry (photographic metrology). Based on results of this research, standards for photographic materials were established in the in the Soviet Union.

Kravets devoted much attention to the history of science. this interest was stimulated by his contacts with lebedev. beginning in 1912 and continuing almost until his death, Kravets studied Lebedev’s school, which has produced many outstanding physicists (N. N.Andreev, V, K. Arkadiev, S. I. Vavilov, P. P. Lazarev, P. S. Epstein, and others). In 1949 he edited (and commented on) Dokumenti po istorii izobretenia fotografii (Documents in the history of the investion of photography). The classics of natural philosophy had always interested Kravets. and many volumes of scientific papers by Newton, Lomonosov, Lenz, H. A. Lorenz, Mendeleev, Monge, and Faraday were published in the soviet union with kravets (and Vavilov )as editor and commentator. kravets also wrote reminiscences of P. N. Lebedev, S. I. Vavilov, and D. S. Rozhdestvenskii among others.

Kravets was a brilliant lecturer. His academic career had begun in 1898, in the department of physics of the Moscow higher Technical School, which was headed by A.A Eichenwald. Before the revolution he also taught at Moscow University and the moscow Pedagogical institute. In 1914 he was named professor at Kharkov university and worked there until 1923, when he was appointed professor at lrkutsk University. From 1930 Kravets taught in leningrad higher schools, and from 1938 he was the head of the department of general physics at Leningrad University.

Kravets’ hobbies were literature, poetry, history. Here he was able to use his talents as lecturer and as storyteller. His work in the history of science was related to this vocational writing.

.Kravets was elected a corresponding member of the Academy of Sciences of the U. S. S. R. in 1943. He received the State Prize of the U. S. S. R. in 1946.

BIBLIOGRAPHY

I. Original Works. Trudi po fizike (works on physics; Moscow, 1959) contains papers by Kravets, including the following: “Absorbtsiia sveta v rastvorakh okrashennikh veshchesty” (Absorption of light in solutions of colored substances; 1912), 33–145; “Predvaritelnaia zametka o prilivakh Baikala” (On tides of Lake Baikal: 1926), 267-–270; “Prakticheskoe i teoreticheskoe znachenie sensi tometry” (The practical and theoretical sense of sensitometry; 1939), 245–252; and’ Nekotoriie noviie danniie o pogloshchenii sveta v rastvorash i adsorbirovannikh sloiskh” (some new data on light adsorption in solutions and in adsorbed [surface] layers; 1950), 191–206. Kravets wrote the introduction to and edited Dokumenti po istorii izobretenia fotografii (Documents in the history of the invention of photography; moscow and leningrad, 1949). See also his ot N’iutona do Vavilova (From Newton to vavilov; Leningrad. 1967).

II. Secondary Literature. G. P. Fuerman, “Torichan Pavlovich Kravets” (obituary), in Uspekhi fizicheskikh nauk, 58 , no. 2 (1956), 183–192; Iu N.Gorokhovskii et al., “K 75-letiiu so dnia rozhdeniia T. P. kravetsa’ (On the seventy-fifth birthday of T.P Kravets), ibid., 44 , no 2 (1951), 301–310; M. Rodovskii, “K semidesiati letiiu T. P. Kravetsa” (T. P. Kravets-on his seventiedth birth day), ibid,. 29 no. I (1946). 212–213; and’ Torichan Pavlovich Kravets (K 75-letiiu so dnia rozhdeniia” (T. P. Kravets [on his seventy-fifth birthday]). In zhurnal tekhnicheskoi fiziki, 21 , no. 4 (1951), 385–388. Papers on Kravets’ and v. Iu Roginskii, Torichan pavlovich kravets (Moscow, 1979.

V. J. Frenkel