Weber, Ernst Heinrich (ĕrnst hĪnˈrĭkh vāˈbər) [key], 1795–1878, German physiologist. He was a professor at the Univ. of Leipzig (1821–71) and is known for his work on touch and for the formulation of Weber's law—that the increase in stimulus necessary to produce an increase in sensation is not fixed but depends on the strength of the preceding stimulus. With his brother Eduard Friedrich Weber, 1806–71, he discovered the inhibitory power of the vagus nerve (1845). With another brother, W. E. Weber, he made studies of acoustics and wave motion.