176 
IvIATURAL HISTORY 
retired enclofure, and faces upon a large and beautiful lake. And 
indeed this fpecies feems fo to delight in large waters, that no in- 
flance occurs of their abounding, but near vafl pools or rivers : 
and in particular it has been remarked that they fwarm in the banks 
of the "Thames in fome places below London-bridge. 
It is curious to obferve with what different degrees of architec- 
tonic fkill Providence has endowed birds of the fame genus, and 
fo nearly correfpondent in their general mode of life ! for while 
the fwallow and the houfe-martin difcover the greateft addrefs in 
railing and fecurely fixing crufts or fhells of loam as cunabvila for 
their young, the bank-martin terebrates a round and regular hole 
in the fand or earth, which is ferpentine, horizontal, and about 
two feet deep. At the inner end of this burrow does this bird de- 
pofit, in a good degree of fafety, her rude neft, confifcing of fine 
gralTes and feathers, ufually goofe-feathers, very inartificially 
laid together. 
Perfeverance will accomplifli any thing : though at firft one 
would be difinclined to believe that this weak bird, with her foft 
and tender bill and claws, fliould ever be able to bore theftubborn 
fand-bank without entirely difabling herfelf : yet with thefe feeble 
inftruments have I feen a pair of them make great difpatch : and 
could remark how much they had fcooped that day by the freHi 
fand which ran down the bank, and was of a different colour from 
that which lay loofe and bleached in the fun. 
In what fpace of time thefe little artifts are able to mine and 
finifh thefe cavities 1 have never been able to difcover, for reafons 
given above but it would be a matter worthy of oblervation, 
where it falls in the way of any naturalift to make his remarks. 
This I have often taken notice of, that feveral holes of different 
depths are left unfinilhed at the end -of fummer. To imagine that 
thefe 
