i6 THE MIGRATIONS OF BIRDS 



Somewhat more startling is a theory of migration 

 elaborated in an anonymous treatise published in 

 London in 1703, "By a Person of Learning and 

 Piety," entitled in part An Essay I'owards the Prob- 

 able Solution of this Question: Whence come the Stork 

 and the T!urtle^ the Crane and the Swallow^ when they 

 know and Observe the appointed time of their Coming. 

 This author in a wordy statement announces his 

 belief that migratory birds, on leaving England, go 

 direct to the moon, where they pass the winter sea- 

 son — truly an outstanding expression of faith in 

 the power of flight of dehcate creatures which, ac- 

 cording to others, are not able to span the moderate 

 expanse of one of the seas ! To continue, this tract 

 sets forth that the journey may require sixty days, 

 during which the voyagers may have no need of food 

 in the rarefied ether through which they pass, or may 

 subsist on their stored-up body supplies of fat as 

 "bears are said to live upon their summer fat all the 

 winter long in Greenland." The matter of restful 

 sleep is easily arranged since, as they fly "where 

 they have no objects to divert them, [they] may 

 shut their eyes, and so swing on fast asleep." The 

 tract continues that as the moon is not a stationary 

 body, if birds leave at the time of full moon they 

 may fly directly in a straight line upward, and at the 

 end of the allotted sixty days the moon will again be 

 full and at the proper location in the heavens to 



