  There is a section in Chandrashekar's ''Newton's Principia for the Common
Reader '', (Clarendon Press, Oxford, 1995) in which he claims to find a small
error in the Principia. . However we believe that there is a mistake of
interpretation underlying Chandra's claim and that the Principia is correct as
it stands. This short paper describes Chandra's misinterpretation of a
geometric construction of Newton and gives an outline of Newton's demonstration
by following the standard English version of the Principia line by line and
converting it into modern mathematical notation in the spirit of Chandra's
book.
