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 proceeding at this rate for nearly two hours, M'Allister came hurrying into our compartment in a state of great excitement.
"Professor," he exclaimed with a gasp, "something's gone wrong altogether, and I don't know what to do!"