48 HUMBLE CREATURES. 



we shall here simply aUude to their presence ia the 

 members now imder consideration. But although we 

 pass thus rapidly over the anatomy of the wings, as 

 being of too scientific a character for tliis treatise, we 

 must not omit to refer to the remarkable effects that 

 they produce, and will dAvell for a moment upon their 

 wonderful operation. 



The rapidity of their vibrations is something in- 

 credible, and the number of these within a given 

 space of time has been approximately ascertaiaed by 

 the following experiment. When a spring is caused 

 to vibrate a certain number of times, it emits a par- 

 ticular tone, and, as the number of its vibrations is 

 increased or dimiaished, this note rises or falls in 

 pitch. Now, this vibration being analogous to that of 

 the wing of an insect, which also emits a musical sound, 

 an apparatus has been constructed wherein a multi- 

 plying-wheel, with a given number of cogs, against 

 which a spring strikes, is made to revolve rapidly. 

 A note being thus produced, varying in pitch accord- 

 ing to the rapidity of the revolutions, the velocity is 

 accelerated or retarded until this note is the same as 

 that proceeding from the wings of the insect, and by 

 an easy calculating process the number of vibrations 

 miay be thus ascertained. 



Messrs. Kirby and Spence inform us that "an 

 anonymous writer in Nicholson's Journal calculates 

 that in its ordinary flight the common House-fly 

 [M. domestica)Tiiak£s, with its wings about 600 strokes, 

 which carry it 5 feet, every second ; but if alarmed," 



