Umov became the head of the Physics department of Moscow State University (MSU) after Aleksandr Stoletov died in 1896.

In 1911, along with a group of leading professors, he left Moscow University in protest of reactionary actions of the government.

The authoritative Encyklopädie der mathematischen Wissenschaften states: N. Umov in 1874 had already solved a problem of the movement of energy in liquid and elastic media in completely generalized view.

However, the intense attention to this view has been attracted only after Poynting had presented a stream of electromagnetic energy based on Maxwell equations [ten years later than Umov's publications].He was the first scientist to indicate interrelation between mass and energy proposing the formula E = kmc2 with 0,5 ≤ k ≤ 1 as early as in 1873.

[1] In 1875, Umov solved a general problem of distribution of electric currents in conducting surfaces of any kind.