372 NATURAL HISTORY 



martins of this district, might be found there, in dif- 

 ferent secret dormitories ; and that, so far from with- 

 drawing into warmer climes, it would appear that they 

 never depart three hundred yards from the village. 



LETTER LVI. 



TO THE SAME. 



THEY who write on natural history cannot too fre- 

 quently advert to instinct, that wonderful limited 

 faculty, which, in some instances, raises the brute 

 creation as it were above reason, and in others leaves 

 them so far below it. Philosophers have defined in- 

 stinct to be that secret influence by which every species 

 is impelled naturally to pursue, at all times, the same 

 way or track, without any teaching or example ; 

 whereas reason, without instruction, would often vary 

 and do that by many methods which instinct effects by 

 one alone. Now this maxim must be taken in a qua- 

 lified sense; for there are instances in which instinct 

 does vary and conform to the circumstances of place 

 and convenience. 



It has been remarked that every species of bird has 

 a mode of nidification peculiar to itself; so that a 

 schoolboy would at once pronounce on the sort of nest 

 before him. This is the case among fields and woods 

 and wilds ; but in the villages round London, where 

 mosses and gossamer, and cotton from vegetables, are 

 hardly to be found, the nest of the chaffinch has not 

 that elegant, finished appearance, nor is it so beautifully 

 studded with lichens, as in a more rural district ; and 

 the wren is obliged to construct its house with straws 

 and dry grasses, which do not give it that rotundity 

 and compactness so remarkable in the edifices of that 



