splashed out
from under the sphere, licked back up its sides, and seemed literally
to shove the great ball up towards the hole in the ceiling.

Its ascent was very slow. As it gained height it looked--save for its
speed--like a fantastic meteor flaming through the night, for the
orange plumage that streamed from beneath lit the ball with dazzling
color. A glowing sphere, it staggered midway between floor and
ceiling, creeping jerkily upwards.

"He's not going to hit the hole!" shouted Guinness.

The borer had not risen in a perfectly straight line; it jarred
against the rim of the hole, and wavered uncertainly. Every second the
roar of its rockets, swollen by echoes, rose in a savage crescendo;
the faces of the three who watched were painted orange in the glow.

The sphere was blind. The man inside could judge his course only by
the feel. As the three who were deserted watched, hoping ardently that
Quade would not be able to find the opening, the left side-rockets
spouted lances of fire, and they knew he had discovered the way to
maneuver the borer laterally. The new flames welded with the exhaust
of the main tubes into a great fan-shaped tail, so brilliant and shot
through with other colors that their eyes could not stand the sight,
except in winks. The borer jerked to the right, but still it could not
find the hole. Then the flames lessened for a moment, and the borer
sank down, to rise again a moment later. Its ascent was so labored
that Phil shouted to Professor Guinness:

"Why so slow?"

And the inventor told him that which he had not seen for the
intolerable light.

"Only half his rockets are on!"

* * * * *

This time the sphere was correctly aimed, however, and it roared
straight into the hole. Immediately the fierce sound of the exhaust
was muffled, and in a few seconds only the fiery plumage, shooting
down from the ceiling, showed where the machine was. Then this
disappeared, and the noise alone was left.

Phil leaped forward, intending to stare up, but Guinness's yell halted
him.

"Not yet! He might still use the disintegrators!"

For many minutes they waited, till the muffled exhaust had died to a
drone. There was a puzzled expression on the professor's face as the
three at last walked over and dared peer up into the hole. Far above,
the splash of orange lit the walls of the tunnel.

"That's funny!" the old man muttered. "He's only using half the
rockets--abou