The punt, checked by the resistance of O'Hara's palms in the water, swung sideways. As it did so Denbigh gathered up the slack of the severed lead-line that still remained on board. Retaining the ends he threw the bight across one of the black objects, at the same time lying at full length on the bottom of the boat. With a jerk that wellnigh capsized the crank craft the punt's way was checked. "Your hippos are barrels, old man!" he exclaimed. "Mines, perhaps," suggested Armstrong. "Be careful, for goodness sake." "Not mines," declared Denbigh. "They wouldn't be floating on the surface. But it's some infernal contrivance. Haul closer and we'll investigate." Warding off the gunwale from the plunging barrel Denbigh dipped his arm into the water. His hand came in contact with a heavy chain eighteen inches beneath the surface. "A boom!" he announced. "By Jove! If we had a slab of gun-cotton handy." "Hist!" exclaimed O'Hara warningly. "I can hear voices." "It's time for us to go," whispered Armstrong. Denbigh cast off. The barrel appeared to leap away from them, as the punt was swept down-stream. "Not much use attempting to land at this point," said Armstrong. "I don't know so much about that," rejoined Denbigh. "Personally I'm rather anxious to see what these fellows are doing ashore. Keep her going, Pat. We'll strike the bank in less than half a mile." Paddling in silence the men pursued their tedious course athwart the current until a dull roar was borne to their ears. "The bore!" exclaimed Armstrong. "It will be quite ten minutes before it reaches us," replied Denbigh. "Stick to it, lads!" The amphibians, with the keen instinct that nature bestowed upon them, also were aware of the approach of the foaming mass of water, for the centre of the river was literally alive with hippopotami and saurians that had not gone ashore for a nocturnal ramble. The crocodiles on the mud-flats were either making for deep water or else crawling higher up the banks out of the rush of the irresistible bore. "Aground!" exclaimed Denbigh as the punt's bows touched the mud. "Check her from swinging round." Armstrong promptly jumped overboard, to sink above his knees in the soft mud. Only by holding on to the gunwale was he able to keep himself from sinking still deeper. "We can't land here," he announced. "We'll be in up to our necks." "Must," declared Denbigh laconically, raising his voice to enable it to be heard above the now loud roar of the approaching bore. Seizing the lead-line and bending one end round his waist Denbigh leapt overboard, threw himself at full length upon the mud, and working with his hands drew himself laboriously over the slimy surface. It was horribly exhausting work, but to his intense satisfaction he found himself making visible progress without sinking beyond a few inches in the ooze. Ahead he could discern the dark outlines of the mangrove forest. It seemed an interminable distance away.