"Keep a tight hold!" shouted Mark, from out of the small window.

"That's th' truest thing yo' ever said!" exclaimed Washington. "You
bet I'm goin' to hold on, and I'm comin' up too," which he proceeded
to do, hand over hand, like a sailor.

The boys and the professor watched the colored man's upward progress.
The ship had hardly begun to settle as, in the excitement, not enough
gas had been let out. Closer and closer came Washington, until he was
able to grasp the edge of the opening, to which the steps were
fastened.

"I thought you weren't coming with us," observed the professor, when
he saw that his helper was safe.

"I changed my mind," said the colored man. "It's jest luck. Seems like
th' ship done wanted me t' go 'long, an' I'm goin'. I'll take my
chances on bein' buried alive. I ain't never seen th' centre of th'
earth, an' I want's to 'fore I die. I'm goin' 'long, Perfessor!"

CHAPTER IV

WHAT DID MARK SEE?

"WELL, I'm glad you've decided at last," the professor remarked. "Now
come inside and we'll see how the ship works."

Once over his fright, Washington made himself at home on the craft he
had helped build. He went from one room to another and observed the
engine.