SHORT-PERIOD VARIABLE STARS.—The recent spectroscopic oobservations of δ Cephei by Belopolsky (NATURE, vol. li. p. 282), and of β Lyræ by Pickering. Lockyer, and others, have shown that we have still a great deal to learn as to the cause of the light-changes in variables of short period other than those of the Algol type. In these inquiries, it has become clear that a study of the light-curves must go hand-in-hand with that of the spectroscopic changes, and we therefore welcome the publication, by Dr. Schur, of new light-curves of δ Cephei, η Aquilæ, and β Lyræ (Ast. Nach. 3282-83). The observations were made at Strassburg in the years 1877-85 by Argelander's method, an opera-glass providing the requisite optical aid.