Alexander Ivanovich Sadovsky (6.12.1859-26.12.1921)-a Russian physicist. Born in Vitebsk. He graduated from St Petersburg University (1881). He taught at institutions of higher education in St Petersburg, and from 1894 was professor at Yuryev University.
In 1898 he was the first to give a theoretical foundation for the rotating action of light waves falling on crystals (the Sadovsky effect), calculated the torques, and proved the possibility of the direct conversion of light energy into mechanical energy. However, these ideas were first appreciated only in 1911, by P. Ehrenfest, and won worldwide recognition. He also developed a spectral method of determining temperature.