nvented learned scientists predicted that the
limit of speed was thirty miles an hour, as the human body could not
stand a higher speed. To-day the human body stands a speed of three
hundred and sixty miles an hour without ill effects. At any rate, on my
first trip I intend to take no chances. We know that the body can stand
an acceleration of thirty-two feet per second without trouble. That is
the rate of acceleration due to gravity and is the rate at which a body
increases speed when it falls. This is the acceleration which I will
use.

"Remember that the space traveled by a falling body in a vacuum is equal
to one half the acceleration multiplied by the square of the elapsed
time. The moon, to which I intend to make my first trip, is only 280,000
miles, or 1,478,400,000 feet, from us. With an acceleration of
thirty-two feet per second, I would pass the moon two hours and forty
minutes after leaving the earth. If I later take another trip, say to
Mars, I will have to find a means of increasing my acceleration,
possibly by the use of the rocket principle. Then will be time enough to
worry about what my body will stand."

A short calculation verified the figures the Doctor had given me, and I
stood convinced.

"Are you really going?" I asked.

"Most decidedly. To repeat, I would have started yesterday, had you
arrived. As it is, I am ready to start at once. We will go back to the
house for a few minutes while I show you the location of an excellent
telescope through which you may watch my progress, and instruct you in
the use of an ultra-short-wave receiver which I am confident will pierce
the heaviest layer. With this I will keep in communication with you,
although I have made no arrangements for you to send messages to me on
this trip. I intend to go to the moon and land. I will take atmosphere
samples through an air port and, if there is an atmosphere which will
support life, I will step out on the surface. If there is not, I will
return to the earth."

* * * * *

A few minutes was enough for me to grasp the simple manipulations which
I would have to perform, and I followed him again to the space flier.

"How are you going to get it out?" I asked.

"Watch," he said.

He worked some levers and the roof of the barn folded back, leaving the
way clear for the departure of the huge projectile. I followed him
inside and he climbed the ladder.

"When I shut the door, go back to th