lthy to interfere with him.

"I'll just let him go, and tell Mr. Jenks about him when he comes
to-night. But I must warn Rad never to let him in here again. He might
damage the airship."

Calling to the colored man, Tom pointed to the stranger, who was almost
out of sight down the road, and said earnestly:

"Rad, do you see that fellow?"

"I sho do, Massa Tom, but I sorter has t' strain my eyes t' do it. He's
goin' laik my mule Boomerang does when he's comm' home t' dinnah."

"That's right, Rad. Well, never let that man set foot inside our fence
again! If he comes, and I'm home, call me. If I'm away, call dad or Mr.
Jackson, and if you're here alone, drive him away, somehow."

"I will, Massa Tom!" exclaimed the colored man, earnestly, "an' if I
can't do it alone, I'll get Boomerang t' help. Once let dat ar' mule
git his heels on a pusson, an' dat pusson ain't goin' t' come bodderin'
around any mo'--that is, not right away."

"I believe you, Rad. Well, keep a lookout for him, and don't let him
in," and with that Tom entered the house to think over matters. They
were beginning to assume an aspect he did not altogether like. Not that
Tom was afraid of danger, but he preferred to meet it in the open, and
the warning, or threat, of the mysterious man disquieted him.

When Mr. Swift came home, a little later, his son told him of the
midnight interview with Mr. Jenks, for, up to this time, the aged
inventor was unaware of it, and Tom also gave an account of the
diamonds, speaking of their value.

"And do you propose to go to Phantom Mountain, in search of the makers
of these gems, Tom?" asked Mr. Swift.

"I had about decided to do so, dad."

"And you're going in the Red Cloud?'

"Yes."

"Who are going with you?"

"Well, Mr. Jenks will go, of course, and I've no doubt but that if I
mention the prospective trip to Mr. Damon, that he'll bless his skating
cap, or something like that, and come along."

"I suppose so, Tom, and I'd like to have you take him. But I think
you'll need some one else."

"Because, from what you have told me, you are going out to a dangerous
part of the country, and you may have to deal with unscrupulous men.
Three of you are hardly enough to cope with them. You ought to have at
least another member of your party. If I was not busy on my invention of
a new wireless motor I would go along, but I can't leave. You might take
Mr. Jackson."

"No, you need him here to help you, dad."

"How