WILLIAMS, W. New Mathematical Demonstrations of Euclid, rendered clear and familiar to the minds of youth, with no other mathematical instruments than the triangular pieces commonly called the Chinese Puzzle. London, 1817. Engraved folding plate, text illustrations and a Chinese Puzzle of 9 triangles in a pocket affixed to back enpaper. 8vo, contemporary morocco, defective; first few pages stained, and lower margin chipped.