William Thomson Lord Kelvin told about Petr Lebedev’s scientific merits in a laconic and aphoristic way: “For the whole of my life, I had been fighting against Maxwell disclaiming his light pressure, while Lebedev’s experiments made me surrender.” The encyclopedia describes the same even more laconically: In 1899, Petr Lebedev, by way of virtuosic, though performed by modest means tests confirmed Maxwell’s theory of light pressure on solids, and in 1907 on gases as well. This research was an important landmark in electromagnetic phenomena science. The professor of Moscow University was famous for not only his experiments but foundation of scholar school as well. He could boast of remarkable wittiness too. One of his jokes once scared his mother to death. The future professor’s mother received a strange letter from him saying: “I have a newborn: she is crying, rioting, and acknowledging no authorities. Professor Kundt was her godfather. He was a little bit excited when I brought the newborn to him…” It was only at the end of long letter that Petr Lebedev explained to his mother that under the term newborn he meant some idea with regard to electricity.