^98 NATURAL HISTORY 



shop's Walthamy in this county, where many 

 sand-martins nestle and breed in the scaf- 

 fold holes of the back-wall of William of 

 Wykeham^ stables : but then this wall 

 stands in a very sequestered and retired 

 enclosure, and faces upon a large and 

 beautiful lake. And indeed this species 

 seems so to delight in large waters, that 

 no instance occurs" of their abounding, but 

 near vast pools or rivers : and in particular 

 it has been remarked that they swarm in 

 the banks of the Thames in some places 

 below London-bridge, 



It is curious to observe with what dif- 

 ferent degrees of architectonic skill Provi- 

 dence has endowed birds of the same genus, 

 and so nearly correspondent in their general 

 mode of life ! for while the swallow and 

 the house-martin discover the greatest ad- 

 dress in raising and securely fixing crusts 

 or shells of loam as cunabula for their 

 young, the bank-martin terebrates a round 

 and regular hole in the sand or earth, which 

 is serpentine, horizontal, and about two feet 

 deep. At the inner end of this burrow 



