as having supplied Newton with the accurate data required for
completing the theory.

The name of Edmund Halley, Second Astronomer Royal, must ever be held
in repute, not only for his own discoveries, but for the part he
played in urging Newton to commit to writing, and present to the Royal
Society, the results of his investigations. But for his friendly
insistence it is possible that the _Principia_ would never have
been written; and but for his generosity in supplying the means the
Royal Society could not have published the book.

[Illustration: DEATH MASK OF SIR ISAAC NEWTON.
Photographed specially for this work from the original, by kind
permission of the Royal Society, London.]

Sir Isaac Newton died in 1727, at the age of eighty-five. His body
lay in state in the Jerusalem Chamber, and was buried in Westminster
Abbey.


FOOTNOTES:

[1] The writer inherited from his father (Professor J. D. Forbes) a
small box containing a bit of wood and a slip of paper, which had been
presented to him by Sir David Brewster. On the paper Sir David had
written these words: "If there be any truth in the story that Newton
was led to the theory of gravitation by the fall of an apple, this bit
of wood is probably a piece of the apple tree from which Newton saw
the apple fall. When I was on a pilgrimage to the house in which
Newton was born, I cut it off an ancient apple tree growing in his