Gear's illustrated catalogue of wood and iron working machinery (1872)
A.S. Gear, Gear, A. S · Boston : Printed at A.S. Gear's printing office, 62 Sudbury Street · leaf 395
strength of construction never previously attained. The more important advantages of this system lay principally in the lengthened bridges, and their being shiftedaway from the edges of the case towards the middle of the sounding-board, whereby larger spaces between the stringswere obtained and… … of Figure C represents the original drawing in Steinway & Sons patent for the overstrung scale, and the dispositionthe strings in the form of a fan. Secured by letters patent No. 26532, dated December 20, 1859. Figure D,
