PROF. HOBATIO SCOTT CARSLAW, whose approaching retirement from the chair of mathematics, pure and applied, at the University of Sydney has just been announced, was appointed to that post some thirty-two years ago. Born in 1870, he is a son of the late Rev. W. H. Carslaw, D.D., of Helensburgh, a well-known writer on the martyrology of the Scottish Reformation and of the Covenants. After graduating at Glasgow, Carslaw proceeded to Cambridge, where, among other distinctions, he gained a Smith's prize and was elected to a fellowship at Emmanuel College. Prof. Carslaw has always taken advantage of the sabbatical years granted periodically by the University of Sydney to renew his connexion with his old college. On the last of these occasions Emmanuel College showed its appreciation of his eminence as a mathematician by re-electing him to a fellowship. The University of Glasgow, in which, before going to Australia, he served for five years as senior lecturer in mathematics, also took this opportunity of conferring on him the honorary degree of LL.D. Prof. Carslaw has been a prolific writer of mathematical papers and textbooks. His “Fourier's Series and Integrals”, published in 1906, is regarded as a standard work. In later and amplified editions, this book has been divided, the part dealing with applications to the “Conduction of Heat” appearing as a separate treatise. In 1912 Carslaw published a translation of Bonola's “Non-Euclidean Geometry”, and in 1916 he produced a textbook of his own on the same subject. Other writings include “An Introduction to the Infinitesimal Calculus” and a “Plane Trigonometry”. To Prof. Carslaw increased leisure means opportunity for further researches; the fruits of these activities are awaited with interest by his many friends.