so use
the moon to give us a fresh start. But for the fact that it would be
best for us to reach the moon before it has waned to any large extent we
might have delayed our start for many days, and, whilst considerably
shortening our journey, still arrived at Mars on the date we have
fixed."

Our chronometer was housed in a substantial non-magnetic cubicle, with a
very thick glass window, in order to protect it from the magnetism and
electricity which pervaded our vessel. On looking at the chronometer I
found the time was nearly eleven o'clock. We had, therefore, been nearly
two hours on our journey and had travelled some three hundred miles,
mostly in an upward direction from the earth; so if there were any of
the earth's atmosphere around our vessel it must be of the most extreme
tenuity, and we might safely increase our speed.

I accordingly gave M'Allister the order to switch on the power
gradually, up to our full speed, and it was not long before we were
rushing through space at the rate of over eighty-three thousand miles an
hour. At this rate, as I told them, we might expect to reach the moon in
a little over sixteen hours, allowing for loss in slackening down at the
latter part of the journey.

"It so happens," I said, "that the moon's present distance from the
earth is rather less than 226,000 miles, being its nearest approach to
the earth during this month."

John at once asked, "How it happened that, if the moon were only this
comparatively short distance away from us, I reckoned it would require
over sixteen hours to reach it at the tremendous speed we were now
moving"; and added, "I thought we should be there in about three hours."

"Ah, John," I replied, "you have forgotten that the earth is rushing
along and carrying the moon with it nearly as fast as we are travelling,
and you are reckoning as though they were standing still all the time.
As a matter of fact we are only gaining on the moon by a little over
fifteen thousand miles an hour, and we must allow for slackening speed
long before we reach the moon, so we cannot expect to cover the distance
in less than sixteen hours. You will see that if we did not travel
faster than the moon is moving away from us we should never catch it up
at all!"

"That explains it all, Professor," said John, "and I must confess I felt
rather puzzled at the length of time required to reach the moon, so was
altogether out in my calculations."

After we had been procee