"I know you are," grinned the other, "that's just why I said it. But, as I was telling you, it sure was a man's job to fight through that stuff yard by yard, and the salt water was just about level with my lips, so that when I wanted a breath I had to give a little jump and breathe before I came down. And those beasts on the buckboard were simply howling with laughter. "'Look at the human jumping-jack!' I heard one of them say, imitating the voice and manner of a sideshow barker, 'The only original half-man, half-frog, in the world. See him hop! One hop is worth the money!' I tell you what," added Roberts, laughing in unison with the rest, at the picture he had conjured up, "I was just about hot enough under the collar to have ducked every one of those grinning oafs." "But did you really think you were going to be drowned, Mr. Roberts?" asked Roger. "I suppose if I had stopped to think, my boy," was the immediate response, "I would have known that the other chaps would have got hold of me long before that, but I felt more than half-way drowned as it was, hardly able to advance a step nearer safety, and only succeeding in getting breath by jumping up and down as if I was on a skipping rope. But when I thought I would have to give out, paying no attention to the jocose suggestions of the fellows, such as 'Get a balloon!' 'Talk about a grasshopper!' 'Look who's here, there's spring-heeled Jack on the trail!' and so forth, and when my strength was nearly at an end, it seemed to me either that I had reached a little hillock or that the water was receding. I stood still, and found that by throwing my head back I could just breathe without making any wild gymnastics, and I thought it a good time to take a breathing space. In a few moments I saw that the water really was receding and half an hour later I made my way to the buckboard, where all the boys had gathered and were sitting smoking, watching my frantic efforts. "'You're a precious lot,' I said to them, as I clambered up out of the wet, 'to let a fellow half drown without coming to help him. I might have gone under out there for all you cared.' Oh, I was mighty sore about it, and I didn't care if they knew it. [Illustration: DENSE SOUTHERN PALM GROVE. Through this lines must be cut to establish Survey points, showing wide range of territory with which a topographer must be familiar. _Photograph by U.S.G.S._] "But the chief, who had been laughing as heartily as any, said: 'Roberts, you know perfectly well that we would have come after you if there had been any danger. But I looked at my watch and saw that it was full time for the tide to turn, so that you really stood in no such awful peril as you seemed to think.' "'That's all very well,' I answered, 'but how was I to know it?'