William Swartzell says JS "intends" to translate papyri in 1838.
William Swartzell, Journal, 26 July 1838; rep. Mormonism Exposed, Being a Journal of a Residence in Missouri from the 28th of May to the 20th of August, 1838 (Pittsburgh, PA: The Author, 1840), 25
26th. Doing nothing to-day, except looking at the hands employed in getting out logs for brother Joseph Smith's house, in which he intends translating the heiroglyphics of the Egyptian mummies.