“Matter? No! Why do you ask?”

“Because you weren’t thinking of what you were saying, that’s all. I can always tell. Do you see anything?”

“To be perfectly frank, Mary, I do. I see a cloud of smoke over there in the direction of Shopton, and when I see smoke I think of fire. As we recently had a little blaze at one of the shops, I am a bit anxious to see if this is another. Of course it will be as well fought with me away as with me there. But still——”

“Oh, Tom, I see it, too!” cried the girl, as a little puff of smoke made itself visible near a wooded part of the country. “Perhaps you’d better head back that way.”

“I think I will,” decided the pilot.

He moved the steering wheel slightly, banked the plane a bit, and was off in another direction, heading directly for the haze of smoke which by this time had considerably increased in volume.

At the time when Tom first saw the smoke menace he was several miles from it, though the clear air made the fire seem nearer than it was. But the Hummer was a speedy craft, and she quickly covered the distance.

As Tom Swift and Mary Nestor approached the blaze—for blaze it was, since they could now notice a redness that betokened flames—they could see it more plainly, and a sense of relief came to the young man when he noted that it was in a spot remote from his shops.

“Guess it’s a forest fire, Mary,” Tom observed. “I thought one would break out soon, it’s been so dry.”

“I’ve never seen a forest fire,” she responded. “It must be very thrilling.”