“Easily answered, Ned; because they are not hot.”
“But they seem to be burning like the flame in a lamp, only of course very small.”
“Seem, Ned, but they are not burning. It’s light without heat, the same as you see on decaying fish; and as we shall find in some of the great mushrooms in the jungle. It is one of the puzzles scientific men have not quite settled yet. We have it, you see, in our own glow-worms. I have often seen it in a kind of centipede at home, which to me seems to be covered with a kind of luminous oil, some of which it leaves behind it on a gravel path or the trunk of a tree.”
“Yes; I’ve seen that,” said Ned thoughtfully.
“Then, again, you have it on the sea-shore, where in calm, hot weather the luminosity looks like pale golden-green oil, so thick that you can skim it from a harbour.”
“But what can it all be for?”
“Ah, there you pose me, Ned. What is everything for? What are we for?”
“To go up the river, and make all sorts of discoveries.”
“A good answer. Then let’s roll ourselves in our blankets and go to sleep. Hamet says that we shall start again before it is light, and they are going to sleep now.”
“All right. Shall I make the beds?”