It is much better to learn the elements of geology, of botany, or ornithology and astronomy by word of mouth from a companion than dully from a book.

There are still many unsolved problems about bird life, among which are the age that birds attain, the exact time at which some birds acquire their adult dress, and the changes which occur in this with years. Little, too, is known about the laws and routes of bird migration, and much less about the final disposition of the untold thousands which are annually produced.