Date: Apr 28, 2011 2:53 PM
Author: cdn
Subject: Harmonic set of points internal/external division NEED HELP

In the James Smart text 'Modern Geometries' on page 214 fig 5.4 A Harmonic set of points is defined as follows:
"In Euclidean Geometry, a harmonic set of points (or harmonic range) is defined to be a set of four collinear points such that the segment determined by two of them is divided internally and externally in the same ratio."

To me this is not plain English. What does it mean to say: "the segment determined by two of them?" And mainly I don't understand this concept of dividing a segment externally.