Conseil had not finished the sentence before I saw what he was driving at.

"I understand," said I; "but that calculation, though simple enough, can give but a very uncertain result."

"Never mind," said Ned Land urgently.

"Here it is, then," said I. "In one hour each man consumes the oxygen contained in twenty gallons of air; and in twenty-four, that contained in 480 gallons. We must, therefore find how many times 480 gallons of air the Nautilus contains."

"Just so," said Conseil.

"Or," I continued, "the size of the Nautilus being 1,500 tons; and one ton holding 200 gallons, it contains 300,000 gallons of air, which, divided by 480, gives a quotient of 625. Which means to say, strictly speaking, that the air contained in the Nautilus would suffice for 625 men for twenty-four hours."

"Six hundred and twenty-five!" repeated Ned.

"But remember that all of us, passengers, sailors, and officers included, would not form a tenth part of that number."

"Still too many for three men," murmured Conseil.