Marin Mersenne (8.09.1588-1.09.1648) was a French scientist. He was born in Oizé (now the department of Maine). He was educated at a Jesuit school and later joined the order of the Minims. He taught philosophy and theology in the order's monasteries.
His physical research was devoted to acoustics, the motion of liquids and the laws of the oscillation of a pendulum. He determined the speed of sound in air (1636). He studied the vibrations of strings and resonance. He established the dependence of the pitch of a sound on the frequency of vibration. He gave a quantitative description of W. Gilbert's observations in the field of electricity and magnetism. In 1636 he proposed the design of a reflecting telescope.
He played an important part in spreading the new scientific knowledge: he kept others informed of the work of other scientists, retelling and commenting on it, and published a good many of their works. In particular, in 1634 he translated Galileo's “Mechanics”, in 1637 he published Descartes's “Dioptrics”, and in 1645 he acquainted French scientists with Torricelli's experiment, which proves the existence of atmospheric pressure; he also promoted Galileo's teaching in France. He corresponded with the well-known scientists of the time R. Descartes, C. Huygens, B. Pascal, E. Torricelli and P. Fermat. From the circle of scientists that gathered around Mersenne the Paris Academy of Sciences was formed in 1666.