Marci Von Kronland, Johannes Marcus

(J. M. Marci z Kronlandu). Born June 13, 1595, in Lanskroun, Bohemia; died Dec. 30, 1667, in Prague. Czech scientist.

Marci studied philosophy and theology at the University of Olomouc and medicine at the University of Prague. In 1632 he became a professor at the University of Prague, and in 1662, rector of that institution. For his scientific works he received a title of nobility and the position of imperial physician-in-ordinary. He analyzed the collision of solid spheres and was the first to state the difference between elastic and inelastic collisions. Marci’s works in optics were his most significant: he gave an explanation of the rainbow and of the coloring of thin films, established the relation between the refraction and chromaticity of a ray, examined the phenomenon of diffraction, and actually applied the principle that was discovered later by C. Huygens and named after him. Marci’s works were largely unknown for a long time.