1911 Encyclopædia Britannica/MacCullagh, James

MACCULLAGH, JAMES (1809–1847), Irish mathematician and physicist, was born in 1809, near Strabane, Ireland. After a brilliant career at Trinity College, Dublin, he was elected fellow in 1832. From 1832 to 1843 he held the chair of mathematics; and during his tenure of this post he improved in a most marked manner the position of his university as a mathematical centre. In 1843 he was transferred to the chair of natural philosophy. Overwork, mainly on subjects beyond the natural range of his powers, induced mental disease; and he died by his own hand in October 1847.

His Works were published in 1880. Their distinguishing feature is the geometry—which has rarely been applied either to pure space problems or to known physical questions such as the rotation of a rigid solid or the properties of Fresnel’s wave-surface with such singular elegance; in this respect his work takes rank with that of Louis Poinsot. One specially remarkable geometrical discovery of MacCullagh’s is that of the “modular generation of surfaces of the second degree”; and a noteworthy contribution to physical optics is his “theorem of the polar plane.” But his methods, which, in less known subjects, were almost entirely tentative, were altogether inadequate to the solution of the more profound physical problems to which his attention was mainly devoted, such as the theory of double refraction, &c. See G. G. Stokes’s “Report on Double Refraction” (B. A. Report, 1862).