DISPERSION

, in Dioptrics, is the divergency of refracted rays of light.

Point of Dispersion, is a point from which refracted rays begin to diverge, when their refraction renders them divergent.—It is called point of dispersion in opposition to the point of concourse, or point in which converging rays concur after refraction. But it is more usual to call the latter the focus, and the former the virtual focus.

Dispersion of Light, occasioned by the refrangibility of the rays, or the nature of the refracting medium. See Aberration, and Inflection.