His maturer years witnessed the overthrow of the last Stuart and the reign of the Dutchman, William of Orange.

In his old age he saw the first of the Hanoverians mount the throne of England.
Within a decade of his death such scientific path-finders as Cavendish, Black, and Priestley were born--men who lived on to the close of the eighteenth century.

In a full sense, then, the age of Newton bridges the gap from that early time of scientific awakening under Kepler and Galileo to the time which we of the twentieth century think of as essentially modern.
THE COMPOSITION OF WHITE LIGHT In December, 1672, Newton was elected a Fellow of the Royal Society, and at this meeting a paper describing his invention of the refracting telescope was read.

A few days later he wrote to the secretary, making some inquiries as to the weekly meetings of the society, and intimating that he had an account of an interesting discovery that he wished to lay before the society.

When this communication was made public, it proved to be an explanation of the discovery of the composition of white light.
We have seen that the question as to the nature of color had commanded the attention of such investigators as Huygens, but that no very satisfactory solution of the question had been attained.