The simplest method of friction is that of the plow, which requires only a fire-board with a gutter in it and a rubbing-stick to push up and down the gutter (Fig. 24). Captain Belmore Browne of Mt. McKinley fame made a fire by this last method when his matches were soaked with water. It is, however, more difficult to produce the fire this way than with the thong and bow. It is still used in the Malay Islands; the natives place the fire-board on a stump or stone, straddle it and with a pointed drill plow the board back and forth until they produce fire. Time: Forty seconds.

Of course it is unnecessary to tell anyone that he can start a fire with a sunglass (Fig. 25) or with the lens of a camera, or with the lens made from two old-fashioned watch crystals held together. But as the sun is not always visible, as lenses are not supposed to grow in the wild woods and were not to be found in the camps and log cabins of the pioneers, and as watch crystals have short lives in the woods, we will pass this method of fire making without matches as one which properly belongs in the classroom.