"Well, wherever we are going, we are bound for the pole, there's some grim satisfaction in that," remarked Frank.
On and on through the cold they drove. The snow had stopped now and suddenly Billy called attention to a strange phenomenon in the southern sky.
It became lit with prismatic colors like a huge curtain, gorgeously illuminated in its ample folds by the rays of myriad colored searchlights.
"Whatever is it?" 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. A nameless dread oppressed all.
Suddenly Frank, after a prolonged scrutiny of the compass, voiced what was becoming a general fear.
"What if we are being drawn by magnetic force toward the pole?"