By William Reed Pages: 283 1906 Much in demand by students of the theory that the earth is hollow and those interested in caves and flying saucers. Contents: Flattening of the Earth at the Poles; Length of Polar Nights; Working of the Compass, Around the Curve; Mysteries of the Polar Regions; The Water-Sky; What It Is; The Aurora, Its Wonderful Variations; Meteors of Volcanic Disturbances; Finding of Rock In and On Ice; Dust in the Arctic; Open Water At the Point Farthest North and South; Why It Is Warmer Near the Poles; The Tidal Wave; The Center of Gravity; What Is In the Interior of the Earth?