On the Migration of Birds. 175 



of nature as does the regulator of a steam-engine, at one time 

 accelerating, at another retarding*. 



By migration this labour is transferred from one zone to 

 the other ; it is indispensable and can only be performed by 

 birds, whose bodily structure corresponds in many respects 

 to peculiar tools. 



A full insight into the nature of the work done by birds 

 will give us a correct notion of their usefulness or injurious- 

 ness to man and lead us to rational action for their protection. 



Some notion of the masses of birds in question may 

 be gathered from an inspection of the hecatombs of winged 

 creatures which year by year during migration shatter their 

 heads through contact with lighthouses. 



I thank you, Gentlemen, for the patience and indulgence 

 with which you have listened to my remarks. 



