We did, but nothing came of it. Indeed if I alone had seen the thing I should have distrusted my senses, should have thought my imagination was playing me false. But they had all seen it. "I shall come down here again with the rifle and watch for an hour or two a day," said Falkner. "Or how would it be to try bait for the beast, whatever it is--eh, Glanton?" "Well you might try to-morrow. Otherwise there isn't much time," I answered. "We trek on Wednesday, remember." Now all hands having grown tired of sitting there, on the watch for what didn't appear, a homeward move was suggested, and duly carried out. We had covered a good part of the distance when Miss Sewin made a discovery, and an unpleasant one. A gold coin which was wont to hang on her watch chain had disappeared. "I must go back," she said. "I wouldn't lose that coin for anything. You know, Mr Glanton, I have a superstition about it." She went on to explain that she had it at the time we had seen the disturbance in the waterhole so that it must have come off on the way down, even if not actually while we were on the rocks up there. Of course I offered to go back and find it for her, but she would not hear of it. She must go herself, and equally of course I couldn't let her go alone. Would I if I could? Well, my only fear was that Falkner would offer his escort. But he did not, only suggesting that as it was late it was not worth while bothering about the thing to-night. He would be sure to find it in the morning when he came up with a rifle to try and investigate the mystery of the pool. But she would not hear of this. She insisted on going back, and--I was jubilant. I knew the coin well by sight. It was of heavy unalloyed gold, thickly stamped with an inscription in Arabic characters. But, as we took our way along the bush path, expecting every moment to catch the gleam of it amid the dust and stones, nothing of the sort rewarded our search, and finally we came to the rocks at the head of the pool. "This is extraordinary and more than disappointing," she said, as a hurried glance around showed no sign of the missing coin. "I know I had it on here because I was fingering it while we were looking at the water. I wouldn't have lost it for anything. What can have become of it, Mr Glanton? Do you think it can have fallen into the water?" "That, of course, isn't impossible," I said. "But--let's have another search." I was bending down with a view to commencing this, when a cry from Aida arrested me. "Oh, there it is. Look." She was standing on the brink of the rocks where they were at their highest above water, peering over. Quickly I was at her side, and following her glance could make out something that glittered. It was in a crevice about five feet below, but as for being able to make it out for certain, why we could not. The crevice was narrow and dark. "I think I can get at that," I said, having taken in the potentialities of hand and foothold.