Almost instantly it ignited and a thick smoke curled up. The bears sniffed uneasily. Any boy who has seen marsh land burned off in the spring knows how swiftly flames spread among dried grass and weeds. The herbage amidst which Tom had flung the blazing bit of wood proved no exception. Fanned by a brisk breeze it ran literally like wildfire among the dried grasses. Luckily the wind was from the side of the hut in which Tom was perched and blew toward the bears. As the flames swept down on them, they uttered loud snorts of terror and turned tail ingloriously.
The mother bear, with her frightened cub, was the first to depart, and she stood not on the order of her going, but galloped off at top speed. The huge male bear lingered but a few minutes longer, then he, too, fled before the fiery terror which Tom's clever strategem had kindled.
"Hooray, boys, they're on the run!" shouted Tom, unable to restrain his enthusiasm.
He swung down his arms and dragged up Jack without much difficulty. Then came Sandy's turn. They had just hauled the Scotch lad to the roof, however, when an alarming thing occurred. The covering of the Aleut hut had not been built to withstand any such strain as the weight of the three lads now perched upon it.
Without warning, save for a sharp crack, it suddenly sagged.
"Look out! It's caving in!" roared Tom.
"Cracky, so it is!" echoed Jack as he felt the sod roof begin to sink under them.
"Roll!" shouted Tom. "Roll down it!"
He seized Sandy, who appeared to be paralyzed from alarm, and gave him a shove. Down the roof rolled the Scotch lad, landing in a heap on the ground, shaken and bruised, but not otherwise injured. Close behind him came Tom and Jack. Behind them the roof fell in with a roar, leaving a big gaping cavity.