So Nellie and her mother were put aboard the warship, after bidding farewell to the captain and crew of the submarine. Mr. Henderson and the boys promised to write to them as soon as they got back from their voyage to the south pole, and, amid a chorus of good-byes the Porpoise resumed her journey.
For several days the submarine forged to the south, and the weather became noticeably cooler. Some of the nights were chilly, and those on watch were glad of the heavy coats they had brought along.
One morning, after a week of travel, when no interruptions had occurred by reason of accidents, old Andy came up on deck, and sniffing the air, said:
"We'll sight ice before night, or I'm a Dutchman."
"What makes you think so?" asked Jack.
"I can smell it," replied the hunter, whereat Jack, and Mark who had joined him, laughed.
"That is no joke," put in Professor Henderson, who, coming up the companionway heard what was said. "Old sea captains will tell you they can smell an iceberg long before they can see it."
"I don't claim to be a sea captain," said Andy, "but I once was on a whaling voyage and I learned to sniff ice in the air. I saved the ship from collision with a berg once."
"Let me see," began the inventor as the adventurers sat about the supper table after the meal was finished, "who have the watches on deck to-night?"
"Washington first and Bill second," replied Jack looking at the chart.