Unbreakable scholastic slate

摘要

777,893. Writing slates. JONES, F. G. April 3, 1956 [June 18, 1955], No. 17667/55. Drawings to Specification. Class 146(2). A writing slate is composed of a sheet of tin plate painted matt black enclosed in a wooden frame which has numbers, letters, colours and scales printed on paper pasted to the sides. Coloured beads on wires are fastened to the opposite sides of the frame.