﻿M. H. Wild on the Absorption of Light by the Air. 293 



of the Tyrolese singer ; but I believe it can be due to no other 

 cause than the close apposition of the arytenoid cartilages through 

 the action of a special muscle, the arytsenoideus proprius ; and 

 this would account for the formation of harmonics. The vocal 

 cord may be regarded as fixed to these two cartilages poste- 

 riorly, which in some measure act as parts of the cords ; so that 

 these two bodies, by pressing against each other, will reduce the 

 length of the cords, very much in the same way as when a finger 

 is applied lightly to a vibrating violoncello-cord. The skill of 

 the singer who wishes to pass very quickly from a chest to a 

 head-note, and to strike the right clear sharp falsetto sound, will 

 be an acquired dexterity of regulating the motion of the arytenoid 

 cartilages so as to cause the air from the chest to act on the length 

 of the cords required for one of their harmonics. If he should 

 in any way miss the exact spot, a cracked sound will be emitted. 

 This will account for the present mode of singing requiring a 

 great deal of practice to be done in perfection. The fact that 

 the cricoid and thyroid cartilages remain nearly motionless, on 

 passing from a chest- to its corresponding falsetto note, would 

 appear to show that falsetto-singing is not due to increased ten- 

 sion of the cords*. 



1 have observed that the mere swelling of the vocal cord may 

 produce a harsh head-note ; this appears to me to be due to the 

 lessened vibrating-property of the cords, the vibrations being 

 prevented from reaching the whole of their breadth. I believe 

 this is not an unfrequent cause of cracked voice from inflamma- 

 tion of the larynx, and that it is not an affection difficult to cure. 



XL. On the Absorption of Light by the Air. 

 By H. WiLDf. 



ATMOSPHERIC air, like other ponderable bodies, is not to 

 be considered a perfectly transparent substance, but, espe- 

 cially in strata of some thickness, exerts an appreciable absorp- 

 tion on transmitted light. Daily experience teaches that this 

 absorption is very different at different times. Distant objects 

 sometimes appear indistinct and hazy in their outlines, as ii they 

 were covered with a veil ; sometimes their details are seen so 

 clearly defined that we are unavoidably led to regard them as 

 brought nearer to us. The first phenomenon is generally ob- 



* It is not impossible, however, that a combined action of the arytsenoi- 

 deus proprius and posterior crico-arytsenoid muscles should add to the ten- 

 sion of the vocal cords in falsetto singing. 



t Translated from Poggendorff's Annalen, No. 8, 1868, having been read 

 before the Naturforschende Gesellschaft of Bern. 



