"There is nothing regular or exact in nature; even our earth is not a perfect sphere.

Nature is never mathematically correct.
You must always allow for variations.

In some parts of the earth its heated core, or whatever it is, must be very, very far down." At this moment a happy thought struck Margaret.
"How easy it would be, Roland, for you to examine this great hole! I can do it; anybody can do it.

It's perfectly amazing when you think of it.

All you have to do is to take your Artesian, ray machine into that building and set it over the hole; then you can light the whole interior, all the way down to the bottom, and with a telescope you can see everything that is in it." "Yes," said he; "but I think I can do it better than that.