loomed up in the storm. When the craft was low enough down so that the superstructure would not scrape the top of the cave, Tom sent her ahead on the level. But he need have had no fears, for the hole was large enough to have admitted a craft twice the size of the Red Cloud.
A few minutes later the airship slid inside the great cavern, as easily as if coming to rest in the yard of Tom's house. The roof of the cave was high over their heads, and they were safe from the storm. The cessation from the deafening sound of the pelting hailstones seemed curious to them at first.
"Well, bless my shoelaces! if this isn't luck!" cried Mr. Damon, as he opened the door of the cabin, and looked about the cave in which they now found themselves. It was comparatively light, for the entrance was very large, though the rear of the cavern was in gloom.
"Yes, indeed, we got to it just in time," agreed Tom. "Now let's see what sort of a place it is. Well have to explore it."
"There may be a landslide, or the roof may come down on our heads," objected Mr. Parker.
"Oh, my dear Parker! please be a little more cheerful," begged Mr. Damon.
The adventurers followed Tom from the airship, and all but the young inventor gazed curi-
