Oakley and I stood in horrified silence, literally unable to move, and the beast advanced a few steps--then stopped to emit that hideous roar--advanced again, and finally halted at a distance of some half-dozen yards from us. A crest of short hair on its forehead was twitching rapidly up and down, and its powerful fangs were bared, and glistening white in the sunshine. It was a repulsive and thrilling exhibition of stark animal brutality, and yet in some strange way it no longer filled me with fear. The attitude of the beast, menacing as it was, seemed to be too humanly blustering, too exaggerated, too "stagey." But when it began advancing again, a real panic seized me, I stepped swiftly back, pointed my revolver point blank at the animal's huge chest and cried a warning to Oakley. As my forefinger closed over the trigger of the automatic, it seemed to require every scrap of my strength to exert the necessary pressure. There was a sharp double crack as Oakley and I fired almost simultaneously, then two more in quick succession from my own revolver, and a deep groan which had something terribly human in it. The gorilla had fallen face forward on the grass, where it was twitching convulsively, and a minute later it was dead. If ever a man felt like a murderer I did. "By my godfather's . . ." breathed Oakley, "that was a thundering near thing. Why didn't you fire before?" "Why didn't _you_?" I gasped. "I couldn't!" "Neither could I. I had to be driven to it by sheer desperation and danger. I don't like the look of the brute; it's too human. Let's get away again, before its brothers and cousins arrive. We're out here to catch 'em, not kill 'em, and I don't want any more blood on my hands to-day." Oakley gave a short, high-strung laugh, and without further delay crossed over to the machine. After a quarter of an hour's examination he made some startling discovery which he tried to explain to me in the usual technical jargon. "What's the cause?" I asked, trying to sound intelligent. "Can't think--and, anyway, it's no use puzzling it out now. I've managed to put it right and so we'd better get away before another storm comes." He clambered into the pilot's seat. I swung the propeller, dashed after the slowly moving machine, ducked and dodged, tried to scramble aboard, failed--and fell. . . . When I had collected my senses again and stumbled to my feet, the machine was gracefully gliding into the air. Shouting and waving my arms, I tried to attract Oakley's attention, but without the least effect. Up and up went the machine, then it suddenly dipped from view, and I was alone with that dead and evil-looking gorilla and the great encircling jungle.