The weather, which, up to this time had been fair, took a sudden turn for the worse about the fourth day after Mark’s little night expedition. One evening the sun sank in a mass of dull lead-colored clouds and a sharp wind sprang up.
“We’re going to have a storm,” said Mr. Henderson. “It’s liable to be a bad one, too, from the way the barometer is falling.”
He looked at the glass, and scanned the various instruments that told how high up the Mermaid was and how fast she was traveling.
“We’re pretty high up in the air,” he said, “and scooting along at about fifty miles an hour. We are going against the wind, too, but fortunately it is not blowing hard.”
At that moment there sounded from without a peculiar howling sound, as if a siren whistle was being blown.
“'Pears like there’s goin’ t’ be a tumultuous demonstration of sub-maxiliary contortions in th’ empherial regions contiguous t’ th’ upper atmosphere!” exclaimed Washington, entering from the engine room into the conning tower.
“What’s the trouble?” asked Mr. Henderson.
“Terrible big black cloud chasin’ us from behind!” exclaimed the colored man.
Noting the alarm in Washington’s voice the professor glanced from the rear window. What he saw caused him to exclaim:
“It’s a cyclone! We must drop down to avoid it!”