resentment in his
voice. The suspicion that anything could be wrong with his shining
darlings was almost a personal offence to him. "But is anything the
matter, my Lord, if I might ask?"

"We're a long way off our course, and for the life of me I can't
understand it," replied Redgrave. "There's nothing about here to pull us
out of our line. Of course the stars--good Lord, I never thought of
that! Look here, Murgatroyd, not a word about this to her ladyship, and
stand by to raise the power by degrees, as I signal to you."

"Ay, my lord. I hope it's nothing bad!"

Redgrave went back to the conning-tower without replying. The only
possible solution of the mystery of the deviation had suddenly dawned
upon him, and a very serious solution it was. He remembered there were
such things as dead suns--the derelicts of the Ocean of Space--vast,
invisible orbs, lightless and lifeless, too distant from any living sun
to be illumined by its rays, and yet exercising the only force left to
them--the force of attraction. Might not one of these have wandered near
enough to the confines of the Solar System to exert this force, a force
of absolutely unknown magnitude, upon the _Astronef_?

He went to the desk beside the instrument-table and plunged into a maze
of mathematics, of masses and weights, angles and distances. Half an
hour later he stood looking at the last symbol on the last sheet of
paper with something like fear. It was the fatal _x_ which remained to
satisfy the last equation, the unknown quantity which represented the
unseen force that was dragging them into the outer wilderness of
insterstellar space, into far-off regions from which, with the remaining
force at his disposal, no return would be possible.

He signalled to Murgatroyd to increase the development of the R. Force
from a tenth to a fifth. Then he went to the lower saloon, where Zaidie
was busy with her usual morning tidy-up. Now that the mystery was
explained there was no reason to keep her in the dark. Indeed, he had
given her his word that he would conceal from her no danger, however
great, that might threaten them when he had once assured himself of its
existence.

She listened to him in silence and without a sign of fear beyond a
little lifting of the eyelids and a little fading of the colour in her
cheeks.

"And if we can't resist this force," she said, when he had finished, "it
will drag us millions--perhaps millions of millions--of miles away from