One visitor, Henry Caswall, an Episcopalian preacher from a St. Louis college, armed himself with an ancient manuscript psalter written in Greek and, pretending to be ignorant of its contents, offered it to Joseph for his scrutiny. Under the prophet's questioning he finally admitted that he believed the language to be Greek, but this Joseph contradicted. Caswall, exaggerating the imperfections of Joseph's grammar, later related the story as follows:

"No, it ain't Greek at all," Joseph said, "except perhaps a few words. What ain't Greek is Egyptian; and what ain't Egyptian is Greek. This book is very valuable. It is a dictionary of Egyptian hieroglyphics." Pointing to the capital letters at the commencement of each verse, he went on: "Them figures is Egyptian hieroglyphics, written in reformed Egyptian. Them characters is like the letters that was engraved on the golden plates."

When the prophet left the room, Caswall turned triumphantly to the men present and exposed the trick. "They appeared confounded for a while," he wrote, "but at length the Mormon doctor said: 'Sometimes Mr. Smith speaks as a prophet, and sometimes as a mere man. If he gave a wrong opinion respecting the book, he spoke as a mere man.'"