This we proceeded to do but did not get very far with it before the Doctor suddenly had qualms of conscience. Trees that could talk could, one would suppose, also _feel_. The thought was dreadful. We hadn’t even the courage to ask the trees about it—yet. So we fell back upon gathering fallen twigs and small branches. This made the work heavier still, because, of course, we needed a great deal of fuel to have fires big enough to see and smell for any distance. After a good deal of discussion we decided that this was a thing which couldn’t be hurried. A great deal depended on its success. It was a nuisance, truly, but we had just got to be patient. So we went back into the jungle-lands and set to work on getting out various samples of woods to try. It took a longish time, for the Doctor and myself were the only ones who could do this work. Chee-Chee tried to help by gathering twigs; but the material we most needed was wood large enough to last a fair time. [Illustration: “_Mostly they were on bare knolls_”] Well, we harvested several different kinds. Some wouldn’t burn at all when we tried them. Others, we found, were pretty fair burners, but not smoky enough. With about the fifth kind of wood, I think it was that we tested out, we nearly had a serious accident. Fire seemed to be (outside of the traces we had found of the smoke signal apparatus) a thing quite unusual in the Moon. There were no traces of forest burnings anywhere, so far as we had explored. It was therefore with a good deal of fear and caution that we struck matches to test out our fuel. About dusk one evening the Doctor set a match to a sort of fern wood (something like a bamboo) and he narrowly escaped a bad burning. The stuff flared up like gunpowder. We took him off, Chee-Chee and I, and examined him. We found he had suffered no serious injuries, though he had had a very close shave. His hands were somewhat blistered and he told us what to get out of the little black bag to relieve the inflammation. We had all noticed that as the wood flared up it sent off dense masses of white smoke. And for hours after the explosion clouds of heavy fumes were still rolling round the hills near us. When we had the Doctor patched up he told us he was sure that we had stumbled by accident on the fuel that had been used for making the smoke signals we had seen from Puddleby. “But my goodness, Doctor,” said I, “what an immense bonfire it must have been to be visible all that distance!—Thousands of tons of the stuff, surely, must have been piled together to make a smudge which could be seen that far.” “And who could have made it?” put in Chee-Chee. For a moment there was silence. Then Polynesia spoke the thought that was in my mind—and I imagine in the Doctor’s too. “The man who made those torches,” said she quietly, “could move an awful lot of timber in one day, I’ll warrant.”