An hour after midnight
Andy Sudds refused to lie down again , although Jack and Mark continued to operate the flying machine . The old hunter sat with a rifle in his hand for the rest of the night . But the professor went to bed . An hour after midnight a cloud from the west completely masked the moon and the whole heavens became misty . This cloud brought both wind and rain , and low upon its edge the lightning played fitfully . `` There will be a heavy tempest about dawn , '' Andy promised the boys . `` I have seen a thunderstorm gather like this before . ''