William Sayre reports to James Cobb that Joseph used the stone from Palmyra to translate the Book of Mormon.
William S. Sayre to James T. Cobb, 31 August 1878 in Dan Vogel, ed. Early Mormon Documents, 5 vols. (Salt Lake City: Signature Books, 2002), 4:145
He Said Smith was poor & was living in a house which had only one room <in which he could keep [for?]> & Smith had a sheet put up in one corner & went behind it from observation when he was writing the bible. He Said Smith kept the bible hid or covered up & put it in a hat & had the Stone which <he> found in Pal=mira & look[e]d through it Sc then wrote what he read in the bible. He Said <he> would not let him see the bible but let him feel of it when it was covered up. Smith read to him a good deal of the bible & he repeated to those in the Stage verse after verse of what Smith had read to him; & I afterwards remem^bered Some of the names <& language> when I read the Mormon bible.