William Burnett states that Joseph pretended that he was inspired to translate through either a stone in a hat or two flat smooth stones.
William Burnett, "Mormonism," New York Weekly Messenger and Young Men’s Advocate (April 29, 1835) from The Pioneer (Rock Springs, Illinois), 4, no. 41 (March 1835): 1
Smith pretended that he had found some golden or brass plates, like the leaves of a book, hid in a box in the earth, to which he was directed by an Angel, in 1827,--that the writing on them was in the "Reformed Egyptian language,"—that he was inspired to interpret the writing, or engraving, by putting a plate in his hat, putting two smooth flat stones, which he found in the box, in the hat, and putting his face therein--that he could not write, but as he translated, one Oliver Cowdery wrote it down.