W. B. Taylor— Becent Researches in Sound. 95 



upon a post 4 feet high ; which while materially increasing the 

 range of the sound — even in the direction of the slight wind, in 

 all other directions doubled the range. This is explained by 

 Professor Reynolds, by the continual waste and destruction of 

 the sound waves which pass along the rough surface of the 

 ground or grass, causing the waves immediately above to 

 diverge continually downward, to be in like manner absorbed ; 

 the effect of which is. to gradually weaken the sound more and 

 more, as the waves proceed; so that even "when there is no 

 wind, the distant sounds which pass above us are more intense 

 than those we hear." (p. 68.) 



[4.] Whatever therefore tends to gradually bend downward 

 tbe sound rays will increase their sensible range. Professor 

 Reynolds found by observations with the anemometer that the 

 velocity of the wind increased from the ground upward ; (pp. 

 63, 64) and hence it must give greater rapidity to the upper i)or- 

 tion of the sound waves in the direction in which it is blowing 

 and cause their impulses to continually tip downward. " This 

 was observed to be the case on all occasions. In the direction of 

 the wind when it was strong, the sound could be heard as well 

 with the head on the ground as when raised, even when in a 

 hollow with the bell hidden from view by the slope of the 

 ground ; and no advantage whatever was gained either by 

 ascending to an elevation, or raising the bell." (p. 68.) 



[5.] " Elevation was found to affect the range of sound 

 against the v/ind in a much more marked manner than at right- 

 angles. Over the grass no sound could be heard with the head 

 on the ground at 20 yanls from the bell, and at 30 yards it was 

 lost with the head 3 feet from the ground, and its full intensity 

 was lost when standing erect at 30 yards. At 70 yards when 

 standing erect the sound was lost' at long intervals, and was 

 only fainily heard even then ; but it became continuous again 

 when the ear was raised 9 feet from the ground, and it reached 

 its full intensity at an elevation of 12 feet." (p. 69.) The 

 same results were obtained with snow on the ground, excepting 

 tbat the sound was heard somewhat lower, being less dissipated 

 or absorbed by the surface contact. At 160 yards the bell was 

 inaudible— even at an elevation of 25 feet, and the sound was 

 supposed to be hopelessly lost ; but at a further elevation of 33 

 feet from the ground, it was again heard ; while at 5 feet lower it 

 was lost. At the proper elevation the sound appeared to be as 

 well heard against the wind as with it, at the same distance. 

 These last two observations very strikingly correspond with 

 and confirm the observations of Henrv [3], and [4J. 



[6.] " The least raising of the bell was followed by a con- 

 siderable intensifying of the sound ;" and while it could be 

 heard only 70 yards when resting on the ground, (i. e., one foot 



