Edward Tullidge gives account of Joseph acquiring mummies and papyri, claims his source is John R. Riggs.
Edward Tullidge, "History of Provo," Tullidge's Quarterly Magazine 3, no. 3 (July 1884): 283
The doctor tells the following story relative to the translation of the Book of Abraham:
When Mr. Chandler arrived in Kirtland with his Egyptian mummies to exhibit, he put up at the hotel of Father Riggs, who, at the request of Chandler, sent his son to the Prophet's house to invite him and family to attend the exhibition that evening, but Joseph was engaged to attend a meeting and could not come. Young Riggs was again sent, with a note asking when Mr. Chandler could have an interview with the Prophet, who replied that he would come in the morning at 8 o'clock, which he did; and young Riggs was present when the Prophet first saw the papyrus from which is translated the Book of Abraham. Joseph was permitted to take the papyrus home with him, Father [Gideon] Riggs vouching for its return, and the morning following Joseph came with the leaves which he had translated, which Oliver Cowdery read, and Mr. Chandler then produced the translation of Professor Anthon as far as the professor could translate it. Dr. Riggs, who was present at the reading, says that the translation of the Prophet and the professor agreed so far, but "there was one language Professor Anthon could not translate which the Prophet did."