  In a recent paper a mathematical model for quantum measurement was presented.
The phenomenon of wave particle duality, which is introduced in every beginning
course of quantum theory, can be explained using this model. Although it is a
special case of the general theory it has historic interest and involves the
use of a continuous spectrum which was treated only casually in the original
article. The treatment here is self contained except for the proof of a
mathematical theorem appearing in the first paper.
