Half past eleven
gasped Billy in an awed tone as the mystic lights glowed and danced in almost blinding radiance and cast strange colored lights about the laboring aeroplane . `` The Aurora Australis , '' said the professor in an almost equally subdued voice , `` the most beautiful of all the polar sky displays . '' `` The Aurora Australis , '' cried Frank , `` then we are near the pole indeed . '' Half past eleven . The lights in the sky began to dim and soon the aeroplane was driving on through solid blackness . The suspense was cruel . Not one of the adventurers had any idea of the conditions they were going to meet .