BIRDS ftND NftTURE. 



ILLUSTRATED BY COLOR PHOTOGRAPHY. 



EARS. 



By W. E. Watt. 



QJ 



(^ HK air is an elastic fluid sur- 

 rounding- the earth. The 

 motions of things whether 

 alive or not, set it in a state 

 of vibration that rarely ceases. At all 

 times and in all places it is pulsing 

 responsively to all that is going on. 



Animals are interested in what is 

 moving about them. It may mean 

 life or death, pleasure or agony, and 

 most animals are keen to know which 

 is for them at any given period. They 

 are therefore equipped with organs 

 that respond to these waves of the air. 

 They are variously equipped, some 

 hearing certain sounds feebly where 

 others are acute to them and deeply 

 moved. Some sounds are full of 

 moment to one organism arousing it 

 to nervous activity while another 

 organism knows nothing of what is so 

 distinctly heard by the first. 



Can a Mule hear more than a 

 Mouse is a question which has agitated 

 many young people who have con- 

 sidered the length of the former's ear 

 and its versatility. A series of experi- 

 ments once conducted in youthful 

 sport by the writer, seemed to settle 

 the matter that each can hear sounds 

 which are unnoticed by the other, and 

 that the ear of the Mouse is much 

 better adapted in hearing powers to 

 the occupation of the Mouse than is 

 that of his long eared neighbor. Cer- 

 tain shrill sounds of whatever degree 



of loudness, cannot be heard by the 

 Mule even when oats might be secured 

 by attending to them, while distant 

 sounds of a heavy character seem to 

 fail to affect the ear of the Mouse. 



The same is noticeable in the hear- 

 ing of people. To some persons a note 

 one octave higher than the highest 

 note of a piano, cannot be heard. 

 Others can hear such a tone, and yet 

 others are made painfully nervous by 

 it without knowing quite what the 

 trouble is. To some the chirp of the 

 Sparrow is the upper limit of hearing, 

 others can hear the voice of the Bat, 

 yet others are able to hear the notes of 

 insects that range higher in pitch 

 than the voice of the Bat. Dr.WoUas- 

 ton says, " As there is nothing in the 

 nature of the atmosphere to prevent 

 the existence of vibrations incompar- 

 ably more frequent than any of which 

 we are conscious, we may imagine 

 that animals like the Grilli (Grass- 

 hoppers) whose powers appear to 

 commence nearly where ours term- 

 inate, may have the faculty of hearing 

 still sharper sounds which we do not 

 know to exist ; and that there may be 

 other insects, hearing nothing in 

 common with us, but endowed with a 

 power of exciting, and a sense which 

 perceives vibrations of the same nature, 

 indeed, as those which constitute our 

 ordinary sounds, but so remote that 

 the animals who perceive them may be 



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