A Treatise on Geometrical Optics

IN the preface to a recent book dealing with photo-graphic optics, Prof. S. P. Thompson expressed the view that Sir John Herschel's article, “On Light,” in the “Encyclopædia Metropolitana” of 1840 marks the culminating point of English writers on optics. Whether this is still the case or not perhaps need hardly be discussed; it may safely be said that Mr. Herman's book, which contains many novel points, constitutes a marked advance, and brings before English students a quantity of information which was not easily accessible to them before.A Treatise on Geometrical Optics.By R. A. Herman, Fellow of Trinity College, Cambridge. Pp. x + 344. (Cambridge: University Press, 1900.)