222 GORILLAS AND CHIMPANZEES 



a great distance it would be difficult to discern the 

 exact quality ; but on one occasion, while stopping 

 over-night in a native town, I was aroused from sleep 

 by a gorilla screaming and beating within a few 

 hundred yards. I put on my boots, took my rifle, 

 and cautiously crossed the open ground between the 

 village and the forest. This brought me within 

 about two hundred yards of the animal. The moon 

 was faintly shining, but I could not see the beast, 

 and I had no desire to approach nearer at such a 

 time, but I heard distinctly every stroke. I believe 

 the sound was made by beating upon a log or piece 

 of dead wood. He was beating with both hands, the 

 strokes alternating with great rapidity, and not unlike 

 the manner in which the natives beat a drum, except 

 that the hand made the same number of strokes, 

 and the strokes were in a constant series, rising 

 and falling from very soft to very loud, and vice versa, 

 A number of these runs followed one another during 

 the time the voice continued. Between the first and 

 second strokes the interval was slightly longer than 

 that between the second and third, and so on through 

 the scale. As the beating increased in loudness the 

 interval shortened in an inverse degree, while in 

 descending the scale the intervals lengthened as the 

 beating softened, and the author of the sound was 

 conscious of this fact. I could trace no relation in 

 time or harmony between the sound of the voice and 

 the beating, except that they began at the same time 

 and ended at the same time. The same series of 

 vocal sounds was repeated each time, beginning on 



