RAPIDITY OF FLIGHT. 71 



ings of their wings, which, acting upon the water above, helps 

 to keep them down. 



Before we proceed to speak of migration, or that instinct which 

 induces birds to visit and retire from certain countries at par- 

 ticular times of the year, it is necessary to say a little on the 

 speed with which they can pass through the air, and their capa- 

 city for continuing on the wing without being fatigued. Pew 

 people, we believe, are aware of the very great rapidity of a 

 bird's flight, and many will doubtless be surprised when they 

 are informed, that even our slower birds can most of them 

 make their way at the rate of thirty miles an hour without 

 any extraordinary effort; but that, if pressed, they can con- 

 siderably exceed that speed. There is an easy way of ascer- 

 taining with tolerable accuracy the rate of a bird's flight, which 

 from experience we can recommend as equally amusing and 

 interesting. It is this : — 



Suppose any bird, a Partridge, for instance, rises in the 

 middle of a stubble, and flies in a straight line over a hedge ; 

 all the observer has to do is to note by the seconds hand of a 

 watch (and those who have not seconds-hand watches may 

 easily learn, at least sufficiently for practical purposes, to count 

 them) the number of seconds between the moment of the bird's 

 rising and that of its topping the hedge ; and then ascertain 

 the distance between the point from whence it rose and the 

 hedge by stepping and counting the number of paces ; when, 

 supposing each pace to be a yard, we have a common Rule of 

 Three sum. Thus, if a Partridge, in three seconds, flies one 

 hundred yards, how many yards will it fly in 3600 seconds, or 



seconds yards seconds 



one hour? or as 3 : 100 : : 3600 : the number of yards 

 required, which will be 36o ° x I0 ° or 120,000 yards, which will 

 amount to (as there are 1760 yards in a mile) about sixty 

 miles an hour. 



Again, suppose some Starlings are seen feeding in a field at 

 a, at no great distance from a church tower, b c, in which they 

 are building ; or a Crow flies from a certain spot to the top of 

 a tree ; we may proceed in the same manner : for the height 

 of the tower or tree will, in most cases, be too inconsiderable 



