The boys were then at a height of about 1,500 feet. The air was bitter chill and warm wraps and furs had been donned long before. Suddenly the aeroplane gave a sickening sidewise dip and seemed about to capsize. Frank caught and righted her just in time. The gyroscopic balance whizzed furiously.
A curious moaning sound became perceptible in the rigging and a wind, which they had not noticed before, lashed their faces with a stinging sensation. The recollection of the falling barometer flashed across Frank's mind. They were in for a storm.
The boy gazed at the compass beneath its binnacle light. As he did so he gave a gasp.
"We are way off our course," he cried, "the wind is out of the north and it is blowing us due south."
"Due south!" exclaimed Harry.
"That's it. And the worst of it is I can do nothing. With this load on board I don't dare try to buck the wind and it's freshening every minute."
"But if we are being blown due south from here, where on earth will we fetch up?" cried Billy, in dismayed tones.
They all looked blank as they awaited the reply. Frank glanced at his watch and then at the compass and made a rapid mental calculation.
"At the rate we are going we should be over the South Pole, roughly speaking, at about midnight," he said.