s, we owe the beginning and early stages to Rene
Descartes.

SUMMARY OF FACTS FOR LECTURES VII AND VIII

Otto Guericke 1602-1686
Hon. Robert Boyle 1626-1691
Huyghens 1629-1695
Christopher Wren 1632-1723
Robert Hooke 1635-1702
NEWTON 1642-1727
Edmund Halley 1656-1742
James Bradley 1692-1762

_Chronology of Newton's Life._

Isaac Newton was born at Woolsthorpe, near Grantham, Lincolnshire, on
Christmas Day, 1642. His father, a small freehold farmer, also named
Isaac, died before his birth. His mother, _nee_ Hannah Ayscough, in two
years married a Mr. Smith, rector of North Witham, but was again left a
widow in 1656. His uncle, W. Ayscough, was rector of a near parish and a
graduate of Trinity College, Cambridge. At the age of fifteen Isaac was
removed from school at Grantham to be made a farmer of, but as it seemed
he would not make a good one his uncle arranged for him to return to
school and thence to Cambridge, where he entered Trinity College as a
sub-sizar in 1661. Studied Descartes's geometry. Found out a method of
infinite series in 1665, and began the invention of Fluxions. In the
same year and the next he was driven from Cambridge by the plague. In
1666, at Woolsthorpe, the apple fell. In 1667 he was elected a fellow of
his college, and in 1669 was specially noted as possessing an
unparalleled genius by Dr. Barrow, first Lucasian Professor of
Mathematics. The same year Dr. Barrow retired from his chair in favour
of Newton, who was thus elected at the age of twenty-six. He lectured
first on optics with great success. Early in 1672 he was elected a
Fellow of the Royal Society, and communicated his researches in optics,
his reflecting telescope, and his discovery of the compound nature of
white light. Annoying controversies arose; but he nevertheless
contributed a good many other most important papers in optics, including
observations in diffraction, and colours of thin plates. He also
invented the modern sextant. In 1672 a letter from Paris was read at the
Royal Society concerning a new and accurate determination of the size of
the earth by Picard. When Newton heard of it he began the _Principia_,
working in silence. In 1684 arose a discussion between Wren, Hooke, and
Halley concerning the law of inverse square as applied to gravity and
the path it would cause the planets to describe. Hooke asserted that he