Three Boys in the Wild North Land

"The author is a missionary in the wild parts of Northern Canada. The setting is the residence of a retired missionary, who invites three teenagers whom he had met during a visit to Britain, to come and stay with him and his wife, and then, using their home as a base, to sample the life style of the missionary in that part of the world.
The boys have to be taught to handle a canoe before they can go anywhere, and then how to handle a gun, with which they will be able to provide themselves with food. That done, they set off on their adventures, which involves many noble exploits, and many hair-raising situations, for instance when confronted by a bear.
The boys all do well, each in turn being the hero of some situation."