varying movements of the sun upon the walls of the buildings, and by
means of fixed pins he marked out the hourly and half-hourly
subdivisions.

At the age of fifteen his mother took him from school, and sent him to
manage the farm and country business at Woolsthorpe, but farming and
marketing did not interest him, and he showed such a passion for study
that eventually he was sent back to school to prepare for Cambridge.

In the year 1660 Newton was admitted into Trinity College, Cambridge.
His attention was first turned to the study of mathematics by a desire
to inquire into the truth of judicial astrology, and he is said to have
discovered the folly of that study by erecting a figure with the aid of
one or two of the problems in Euclid. The propositions contained in
Euclid he regarded as self-evident; and, without any preliminary study,
he made himself master of Descartes' "Geometry" by his genius and
patient application. Dr. Wallis's "Arithmetic of Infinites," Sanderson's
"Logic," and the "Optics" of Kepler, were among the books which he
studied with care; and he is reported to have found himself more deeply
versed in some branches of knowledge than the tutor who directed his
studies.

In 1665 Newton took his Bachelor of Arts degree, and in 1666, in
consequence of the breaking out of the plague, he retired to
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 whi