Suddenly, above the ringing in his ears, came a sound from his gate alarm. Its deep hollow tone was strangely resonant in all that blanket of smoke. He darted back, where lay his bombs and the short fuse laid to the cannon. The smudge had, unfortunately, fallen like a pall, concealing all the trail. It lifted slightly, however, as a fog may lift over waters, revealing one half-seen form upon the ledge. Then, in the second that Grenville laid his fire to the powder, his second alarm, from the frame of bamboo buckets, hung behind him on the wall, rattled out its xylophonic warning. The head-hunting demons, front and rear, were practically upon him! He fired the gun. Its orange flame shot out through the smoke in ragged spears, mingling the fume of imperfect powder with all that reek from the jungle. A gap was apparently torn in the rolling cloud, to be filled with a denser substance. Nothing could possibly be discerned where the charge must have splattered on the wall. There were cries in the air, but whether from pain, or the Dyaks' exultation, Grenville could never have told. Aware that the demons were capable of sacrificing some of their number to the gun, to beget its discharge, and thus clear the way for concerted attack by greater numbers, Grenville promptly lighted the fuse of a bomb and hurled it from him down the trail. It burst in the smoke, its red blot of fire a lurid illumination in the black and gray billows from the smudge. Again a cry succeeded, this one unquestionably voicing some wretch's mortal agony in the all-concealing fume. Without for a moment pausing, Grenville plunged swiftly through the drifting envelope, to gain the brink at the rear. He caught up a rock as he stumbled half blindly onward, and blew on the fire of his brand. A thicker shroud of the reek revolved about him, halting him there to gasp for breath, which he stooped in the hope of finding. He dropped the stone as a useless burden. Once more he staggered onward--and blundered against a Dyak, more blinded than himself! The creature had scaled the wall despite the bamboo framework and its cups, or wooden bells! He and Sidney were instantly locked in a fierce and deadly embrace! A battle as silent as it was swift and ferocious was curtained there in the smoke. That the edge was near was a knowledge equally shared, as each man wrestled in desperate violence to overcome his antagonist and hurl him down to the sea. More by instinct than design, Grenville had paused to grip his firebrand hotly between his teeth. He had seen that the head-hunter held a knife, which was instantly turned, as the boatman writhed in Sidney's arms, in an effort to sink it to the hilt.