CONCLUSION
Could they live to reach the surface? was the thought in the mind of every one. The heat was terrific. They were breathing in gasps. Professor Henderson went to the water tank, thinking to throw some of the fluid over himself and his companions, but he found it so warm that it almost burned his hand.
"Keep up your courage!" exclaimed the inventor. "We will soon be at the top!"
Almost as he spoke the Porpoise bounded from the waves, and fell back in a splash of foam on the surface of the billows. They were at the surface.
The professor rushed for the manhole and soon opened it. He crawled out on the deck, followed by the others. They breathed in deep breaths of the fresh air.
The submarine continued to sail on. Every minute the sea seemed to boil more violently, until at last the waves were covered with a cloud of steam, through which it was difficult to observe where they were going.
"Hadn't we better turn back," suggested Mark.
"Our only hope is to press on," replied Mr. Henderson. "We may cross this zone of boiling water soon."
He went into the conning tower to make an observation. He came on the deck the next minute, very much excited.
"What's the matter? Are we sinking?" asked Andy.