of the pterodactyls. These were old volcanic vents, and for some reason excited the greatest interest in Lord John. What attracted Challenger, on the other hand, was a bubbling, gurgling mud geyser, where some strange gas formed great bursting bubbles upon the surface. He thrust a hollow reed into it and cried out with delight like a schoolboy then he was able, on touching it with a lighted match, to cause a sharp explosion and a blue flame at the far end of the tube. Still more pleased was he when, inverting a leathern pouch over the end of the reed, and so filling it with the gas, he was able to send it soaring up into the air.
"An inflammable gas, and one markedly lighter than the atmosphere. I should say beyond doubt that it contained a considerable proportion of free hydrogen. The resources of G.E.C. are not yet exhausted, my young friend. I may yet show you how a great mind moulds all Nature to its use." He swelled with some secret purpose, but would say no more.
There was nothing which we could see upon the shore which seemed to me so wonderful as the great sheet of water before us. Our numbers and our noise had frightened all living creatures away, and save for a few pterodactyls, which soared round high above our heads while they waited for the carrion, all was still around the camp. But it was different out upon the rose-tinted waters of the central lake. It boiled and heaved with strange
