the i8th century Russian thought was still unable to state general laws and could only observe phenomena in part; but in course of time experiment produced a greater knowledge of scientific law, above all in the physical and chemical sciences studied at the Imperial Academy. Before Euler published his Dioptrics, Rihmann had already made some experiments in electricity in which Lomonosov had a certain share; this high-spirited Russian man of science wrote also on optics and formulated some fundamental propositions concerning the mechanical theory of heat. Somewhat later, in the first half of the nineteenth century, besides Lenz and Kupfer, Petrov, one of their Russian colleagues, acquired some renown in practical physics.
Theoretical physics were further elucidated by Umov and partly by Hvolson, famous as well for his actinometrical studies. At the same time the experimental spirit, further cultivated by Stolyetov and others, attained its highest point in the famous investigations of Lebedev on the pressure of light, and manifested itself in the valuable seismographic observations and inventions of Prince Golitsin.
In course of time the physical interpretation of natural phenomena was applied also to the study of weather: Kraft and Lomonosov had been aware of the importance of systematic meteorological observations, but these were not organized till much later, particularly after the foundation of the chief Physical Observatory (1849), by Kupfer and Wild; the materials collected under their direction, in different parts of the Empire, were studied by Veselovsky, Voyeikov, Klosovsky and others.
