2/6 THE SWALLOW. 



" But how now stands the wind ? 

 Into what corner peers my halcyon's bill ? " 



For brightness and beauty of plumage, the kingfisher 

 has no equal amongst our British birds, and so straight 

 and rapid withal is its line of flight, that when the sun- 

 light falls upon its bright blue back, it seems as if an 

 azure bolt from a crossbow had been suddenly shot across 

 our path. 



It is difficult to calculate or limit the speed which can 

 be produced by the effort of a wing's vibration. We may, 

 nevertheless, ascertain with tolerable accuracy the rate of 

 a bird's flight, as follows : If we note the number of 

 seconds which are occupied by a bird in passing between 

 two fixed points in its line of flight, and measure the 

 distance between these points, we resolve the question to 

 a simple " rule-of-three " sum ; inasmuch as, knowing the 

 number of yards flown in a certain number of seconds, we 

 can ascertain the distance traversed in 3,600 seconds, or an 

 hour, and thus obtain the rate of speed per hour ; sup- 

 posing, of course, the speed to be uniform. In this way 

 the flight of the common Swallow (Hirundo rustled) has 

 been computed at ninety miles, 



" As swift as swallow flies." 



Titus Andronicus, Act iv. Sc. 2 ; 



while that of the swift has been conjectured to be nearly 

 one hundred and eighty miles per hour. 



