New on the website of the Interpreter Foundation:
Appendix E of Ronald E. Romig, Eighth Witness: The Biography of John Whitmer (Independence, MO: John Whitmer Books, 2014), 526-527, features the text of an interview conducted in April 1878 by P. Wilhelm Poulson with John Whitmer, one of the Eight Witnesses:
I — I am aware that your name is affixed to the testimony in the Book of Mormon that you saw the plates?
He — It is so, and that testimony is true.
I — Did you handle the plates with your hands?
He — I did so!
I — Then they were a material substance?
He — Yes, as material as anything can be.
I — Were they heavy to lift?
He — Yes, and as you know gold is a heavy metal; they were very heavy.
I — How big were the leaves?
He — So far as I recollect, 8 by 6 or seven inches.
I — Were the leaves thick?
He — Yes, just so thick, that characters could be en graven on both sides.
I — How were the leaves joined together?
He — In three rings, each one in the shape of a D with the straight line towards the center.
I — In what place did you see the plates?
He — In Joseph Smith’s house; he had them there.
I — Did you see them covered with a cloth?
He — No. He handed them uncovered into our hands, and we turned the leaves sufficient to satisfy us.
During the winter of 1830-1831, Oliver Cowdery, Peter Whitmer, Parley Pratt, and Ziba Peterson traveled from New York to Missouri and back on a mission to Lamanites on the western frontier. Of the four, two were among the Witnesses to the Book of Mormon. Oliver Cowdery was one of the Three Witnesses, whereas Peter Whitmer was one of the Eight. Lyman Wight, who was a member of Sidney Rigdon’s Campbellite congregation in the area of Kirtland, Ohio, recalled attending a meeting in early November 1830 in which “one [presumably Oliver Cowdery] testified that he had seen angels, and another [presumably Peter Whitmer Jr.] that he had seen the plates.” (Romig, Eighth Witness, 87)