“Light the lanthorn.”
“Shall we take our loads with us, uncle?” I said.
“Certainly. If the way through is short we shall want them at the other side. If it is long we shall want some refreshments on the way.”
“But suppose—” I began, and then I stopped.
“Suppose what?” said my uncle.
“Suppose the river does not pass through the mountain, but comes from deep down somewhere.”
“The more interesting the discovery of its hidden source, my lad. But that is not likely. Look at the rock. What is it—granite or gneiss?”
“No,” I said; “limestone.”
“Well, you ought to know how limestone ridges are honeycombed with water-formed caverns. We have several examples at home. If this subterranean river came bubbling up from somewhere in the interior and the rock were granite, I should expect it to be hot.”
“And it’s quite cold, sir,” said Cross.