We keep rushing upwards and in half an hour we know that we must be about fifty miles from the earth, as we have been traveling at the rate of one hundred miles per hour. The air at this height is so rare that we could not possibly live in it. It is a good thing that we are in an enclosed cabin, and have plenty of fresh air in liquid form, which gives off ordinary air just at the rate we require it.
We know that in about an hour and a half we should be clear of the atmosphere altogether, and that we may travel thereafter at the speed of light, which means about eleven million miles per minute.
One little girl says she is feeling very sleepy, and as she was too excited to sleep much last night, I advise her to lie down and have a sleep now; we shall waken her when we arrive at the moon.
Imagine then that we have arrived at the moon. It looks like our own world, "the earth," only there is nothing growing on it; it seems to be all bare rocks. But the mountains look very high; some of them are really higher than the highest mountains on the earth.
Most of the children in our cabin say that they thought the moon was quite smooth, and had a sort of polished surface. When they were told that the moon did not send out light, but merely reflected the light of the sun, they pictured some sort of mirror-like surface.
We are startled by a sudden cry of surprise behind us; the little girl who was sleeping has wakened up, and looking out of the window behind us, she calls: "Oh! look how huge the moon has grown! It is far, far bigger than the sun!"
Looking out at her window, we see what does look like a giant moon. But our little friend is very much surprised when I tell her that that is old Mother Earth, and that the rocky mountains close to us are part of the moon. But how can the earth shine like the moon? In exactly the same way as the moon shines; both merely reflect the light sent out by the sun.
We can scarcely believe that this "huge half-moon", standing out so clearly against a jet-black sky, is really the earth which we left a few hours ago in broad daylight. But the people on the part of it which we speak of as shining like the moon are still in broad daylight. Those people living on the half of the great globe which appears dark to us are in darkness except for the light which is reaching them from this moon up here where we are at present.
One boy says that some of the astronomers on the earth may be looking at us through their telescopes, and he starts making Boy Scout signals with his arms. He is disappointed when I tell him that the very best telescope on earth would not enable the astronomers to see our flying machine even as a speck on the face of the moon. If our machine had been as big as one of our largest buildings, it could then have been seen as a tiny dot.
But we cannot help staring at that great ball on which we live, and which we left so recently. This distant view gives us a good idea of how much bigger the earth is than the moon. Of course if you look down at the moon at present you can get no idea of its size; you can see only a small part of it, just as you could see only a small part of the earth until you made this imaginary voyage skywards. But you can remember what the moon looked like when you saw it from the earth.