This book, an ambitious treatise on the dispersion of light, examines the intersection of dispersion with other branches of optics, particularly as it relates to the undulatory theory. The author acknowledges that the undulatory theory is not without its detractors, and that objections have been made which are "not to be set down to ignorance," but he nonetheless maintains the theory as "the only course...where it seems defective...to recur to and endeavour to remodel its first principles." The author claims not to engage in the "controversy" between proponents of emission and undulation theories, but instead to offer illustrated explanations of the wave theory, to explore its mathematical principles, and to test them against a wide range of experimental observations. Given the relatively recent adoption of the undulatory theory, the author acknowledges that the work is not and cannot be comprehensive, and that much remains to be done. Still, the author's ambition to compile "every thing that can be said" on the subject, thereby providing a text for the student and a sourcebook for the scholar, makes this volume a useful edition to the historical literature of the subject.