In 1665 the great plague broke in England and Cambridge was closed — Newton had to return home for eighteen months. It was the most important period in his life when he made his three great discoveries— those of the differential calculuses, of the nature of white light and of the law of gravitation. He advanced an idea that light consisted of small particles — corpuscles (today the scientists call them photons). Later on he, however, came to the conclusion that light had a dual nature, namely, it was a combination of the corpuscles and the ethereal waves. Newton was also interested in the problem of what was the cause of the motion of the planets. He came to the conclusion that the force that kept the planets in the orbits round the Sun was the same force that caused objects to fall onto the ground, namely, the force of gravity. A popular legend says that he made this discovery while observing the fall of an apple from a tree in his garden. But only in 1684 Newton published his famous book the “Principia” in which he explained the movement of the planets and laid down the law of universal gravitation. This book made a great contribution to Physics and Mathematics: the publication of the “Principia” was compared to a sunrise, but Newton himself was always modest.

Newton was not only theorist but a great inventor, too: he invented a mirror telescope. The demonstration of the mirror telescope made a great impression on the contemporaries and in 1672 Newton was elected a member of the Royal Scientific Society. In 1695 Newton was appointed an inspector at the Royal Mint; there he was in charge of coining new English money. In 1703 Newton was elected a President of the Royal Scientific Society. For the last time he attended its meeting in February, 1727. On March 20, the same year he died and was buried in Westminster Abbey. There is a monument to Newton in Trinity College at Cambridge with the inscription: “Newton Who Surpassed All Men of Science”.