Curious and manifold as are the trees associated with the great names of their planters, or those who have sojourned in their shade, the Tree which, by the falling of its fruit, suggested to Newton the idea of Gravity, is of paramount interest. It appears that, in the autumn of 1665, Newton left his college at Cambridge for his paternal home at Woolsthorpe. “When sitting alone in the garden,” says Sir David Brewster, “and speculating on the power of gravity, it occurred to him, that as the same power by which the apple fell to the ground was not sensibly diminished at the greatest distance from the centre of the earth to which we can reach, neither at the summits of the loftiest spires, nor on the tops of the highest mountains, it might extend to the moon and retain her in her orbit, in the same manner as it bends into a curve a stone or a cannon-ball when projected in a straight line from the surface of the earth.”--_Life of Newton_, vol. i. p. 26. Sir David Brewster notes, that neither Pemberton nor Whiston, who received from Newton himself his first ideas of gravity, records this story of the falling apple. It was mentioned, however, to Voltaire by Catherine Barton, Newton’s niece; and to Mr. Green by Martin Folkes, President of the Royal Society. Sir David Brewster saw the reputed apple-tree in 1814, and brought away a portion of one of its roots. The tree was so much decayed that it was cut down in 1820, and the wood of it carefully preserved by Mr. Turnor, of Stoke Rocheford.
De Morgan (in _Notes and Queries_, 2d series, No. 139, p. 169) questions whether the fruit was an apple, and maintains that the anecdote rests upon very slight authority; more especially as the idea had for many years been floating before the minds of physical inquirers; although Newton cleared away the confusions and difficulties which prevented very able men from proceeding beyond conjecture, and by this means established _universal_ gravitation.
“It may be justly said,” observes Halley, “that so many and so valuable philosophical truths as are herein discovered and put past dispute were never yet owing to the capacity and industry of any one man.” “The importance and generality of the discoveries,” says Laplace, “and the immense number of original and profound views, which have been the germ of the most brilliant theories of the philosophers of this (18th) century, and all presented with much elegance, will ensure to the work on the _Mathematical Principles of Natural Philosophy_ a preëminence above all the other productions of human genius.”