"The light," I said as we stood examining one of these objects, "is certainly phosphorescent. But what is that fluid in the glass?" "I can't tell you, Bill. It may be some vegetable juice. There is, by the way, a Brazilian plant, called _Euphorbia phosphorea_, the juice of which is luminous. This may be something similar. Who knows?"[9] [Footnote 9: "One dark night, about the beginning of December, while passing along the streets of the Villa de Natividada, I observed some boys amusing themselves with some luminous object, which I at first supposed to be a kind of large fire-fly; but on making inquiry, I found it to be a beautiful phosphorescent Fungus, belonging to the genus Agaricus.... The whole plant gives out at night a bright phosphorescent light, of a pale greenish hue, similar to that emitted by the larger fire-flies, or by those curious soft-bodied marine animals, the Pyrosomae. From this circumstance, and from growing on a palm, it is called by the inhabitants 'Flor de Coco.' The light given out by a few of these Fungi in a dark room was sufficient to read by."--George Gardner.] Each of the Dromans took up his or her knapsack, and we were under way again. It was the right branch of the tunnel into which the route led us. That fact Rhodes put down in his notebook. I could see no necessity for such a record, for surely we could not forget the fact, even if we tried. "We'll record it," said Milton, "certitude to the contrary notwithstanding. And we'll keep adding to the record as we go down, too. There's no telling, remember. It may not be so easy to find the way out of this place as it seems." "You said," I reminded him, "that we may never want to return." "And I say it again. But I say this too: we may be mighty glad indeed to get out!" To which I added the quite supererogatory remark that it was clearly within the realm of possibility that we should. Soon the slope of the passage was no longer gentle. An hour or so, and the descent was so steep and difficult that we had to exercise every caution and care in going down it. "Noon" found us still toiling down that steep and tortuous way. We then halted for luncheon. The Dromans ate and drank very sparingly, though this work gives one a most remarkable appetite. Rhodes and I endeavored to emulate their example. I am afraid, however, that it was not with any remarkable success. As it was, the lunch left me as hungry as a cormorant. As we sat there resting, the Dromans held a low and earnest colloquy. The two girls, though, had but very little to say. The subject of the dialogue was an utter mystery to us. Only one thing could we tell, and that was that the matter which they were revolving was one of some gravity. Once and only once did we hear the word Drome.