Having explained to us about the Three Witnesses that will be raised up in the latter days, Moroni now goes back to the history of the Jaredites. He has already told us about Mahonri seeing the finger of God and then being allowed to see the prophetic history of the world.
It is interesting that the brother of Jared surmised without being actually told that if God would touched each of the sixteen transparent stones they would provide illumination for each of the eight large barges. Scientifically speaking, we have many details concerning these barges which we have not yet been able to figure out. For example, this is particularly true with reference to the amount of food and fresh water which would be needed to meet the needs of the animals as well as the people being transported on these barges.