W.W. Phelps recounts that Harris declared that Joseph used silver spectacles to translate the BOM.

[H]e [Martin Harris] is honest, and sincerely declares upon his soul’s salvation that the book is true, and was interpreted by Joseph Smith, through a pair of silver spectacles, found with the plates. The places where they dug for the plates, in Manchester, are to be seen. When the plates were said to have been found, a copy of one or two lines of the characters, were taken by Mr. Harris to Utica, Albany and New York; at New York, they were shown to Dr. Mitchell, and he referred to professor Anthon who translated and declared them to be the ancient short-hand Egyptian. So much is true. The family of Smiths is poor, and generally ignorant in common learning.