Woolsthorpe. In 1668 he took his Master of Arts degree, and was
appointed to a senior fellowship. And in 1669 he was made Lucasian
professor of mathematics.

During the years 1666-69, Newton was engaged in optical researches which
culminated in his invention of the first reflecting telescope. On
January 11, 1761, it was announced to the Royal Society that his
reflecting telescope had been shown to the king, and had been examined
by the president, Sir Robert Murray, Sir Paul Neale, and Sit Christopher
Wren.

In the course of his optical researches, Newton discovered the different
refrangibility of different rays of light, and in his professorial
lectures during the years 1669, 1670, and 1671 he announced his
discoveries; but not till 1672 did he communicate them to the Royal
Society. No sooner were these discoveries given to the world than they
were opposed with a degree of virulence and ignorance which have seldom
been combined in scientific controversy. The most distinguished of his
opponents were Robert Hooke and Huyghens. Both attacked his theory from
the standpoint of the undulatory theory of light which they upheld.


_II.--The Colours of Natural Bodies_


In examining the nature and origin of colours as the component parts of
white light, the attention of Newton was directed to the explanation of
the colours of natural bodies. His earliest researches on this subject
were communicated, in his "Discourse on Light and Colours," to the Royal
Society in 1675.