Their final departure from their island camp was caused by an accident. They had decided to row to the southern end of the lake, and engage a team to meet them the following week, and to carry them to Glenn's Falls, where they intended to ship the boat on board a canal-boat bound for New York, and to return home by rail. To avoid the heat of the sun, they started down the lake immediately after breakfast, and forgot to put out the fire before they left the island.
After they had rowed at least a mile, Tom, who sat facing the stern, noticed a light wreath of smoke rising from the island, and remarked, "Our fire is burning yet; we ought not to have gone and left it."
Harry looked back, and saw that the cloud of smoke was rapidly increasing.
"It's not the fire that's making all that smoke," he exclaimed.
"What is it, then?" asked Tom.
"Perhaps it's water," said Joe. "I always thought that where there was smoke there must be fire; but Harry says it isn't fire."
"I mean," continued Harry, "that we didn't leave fire enough to make so much smoke. It must have spread and caught something."
"Caught the tent, most likely," said Tom. "Let's row back right away and put it out."
"What's the use?" interrupted Jim. "That tent is as dry as tinder, and will burn up before we can get half way there."
"We must get back as soon as we can," cried Harry. "All our things are in the tent. Row your best, boys, and we may save them yet."