Note 107 — Chapter IX · UNIVERSAL GRAVITATION.
Reading edition
It is commonly stated that Newton’s value of the motion of the moon’s apses was only about half the true value. In a scholium of the Principia to prop. 35 of the third book, given in the first edition but afterwards omitted, he estimated the annual motion at 40°, the observed value being about 41°. In one of his unpublished papers, contained in the Portsmouth collection, he arrived at 39° by a process which he evidently regarded as not altogether satisfactory.