In personal appearance Mr. Colburn was decidedly pleasing. His height was five feet ten, and his figure was well proportioned. His face was one not to be forgotten; it indicated sweetness of disposition, benevolence, intelligence, and refinement. His mental operations were not rapid, and it was only by great patience and long continued thought that he achieved his objects. He was not fluent in conversation; his hesitancy of speech, however, was not so great when with friends as with strangers. The tendency of his mind was toward the practical in knowledge; his study was to simplify science, and to make it accessible to common minds. Mr. Colburn will live in educational history as the author of "Warren Colburn's First Lessons," one of the very best books ever written, and which, for a quarter of a century, was in almost universal use as a text-book in the best common schools, not only in the primary and intermediate grades, but also in the grammar school classes. In accordance with the method of this famous book, the pupils were taught in a natural way, a knowledge of the fundamental principles of arithmetic. By its use they developed the ability to solve mentally and with great facility all of the simple questions likely to occur in the every day business of common life. Undoubtedly Pestalozzi first conceived the idea of the true "inductive method" of teaching numbers; but it was Mr. Colburn who adapted it to the needs of the children of the common elementary schools. It has wrought a great change in teaching, and placed Warren Colburn on the roll as one of the educational benefactors of his age. He died at Lowell, Mass., Sept. 13, 1883, at the age of 90 years.--_Journal of Education_. * * * * * THURY'S DYNAMO-ELECTRIC MACHINE. Thury's dynamo-electric machine, which presents some peculiarities, has never to our knowledge been employed outside of Sweden and a few neighboring regions; but this is doubtless due to some personal motive or other of its constructors, since it has, it would seem, given excellent results in every application that has been made of it. It is represented in perspective in Fig. 1, and in longitudinal section and elevation in Figs. 2 and 3. As may be seen, it is a multipolar (6-pole) machine in which an attempt has been made to utilize magnetically, as far as possible, all the iron used in the frame. For this reason the system has been given the form of a hexagonal prism, whose faces are formed of flat electro-magnets, A, A, xxx, constituting the inductors. The internal angles of this prism are filled by polar expansions, P, P, xxx, alternately north and south, that thus form in the interior of the apparatus an inscribed cylinder designed to receive the armature. This latter belongs to the kinds that are wound upon a cylinder in which the wire is external thereto.