NATURAL HISTORY 
LETTER LVL 
TO THE SAME. 
They who write on natural hiftory cannot too frequently'^advert 
to inJlinB, that wonderful limited faculty, which, in fome inftances, 
raifes the brute creation as it were above reafon, and in others 
leaves them fo far below it. Philofophers have defined hipnB to 
be that fecret influence by which every fpecies is impelled naturally 
to purine, at all times, the fame way or track, without any teach- 
ing or example ; whereas reafon^ without inflruftion, would often 
vary and do that by many methods which inJiinH effects by one 
alone. Now this maxim muft be taken in a qualified fenfe; for 
there are inftances in which inJiinB does vary and conform to the 
circumftances of place and convenience. 
It has been remarked that every fpecies of bird has a mode of 
nidification peculiar to itfelf ; fo that a fchool-boy would at once 
pronounce on the fort of neft before him. This is the cafe among 
fields and woods, and wilds ; but, in the villages round London, 
where mofifes and goflamer, and cotton from vegetables, are hardly 
to be found, the neft of the chaffinch has not that elegant 
finilhed appearance, nor is it fo beautifully fludded with Uchens, 
as in a more rural diftrid: : and the 7vren is obliged to conftrud 
it's houfe with ftraws and dry graffes, which do not give it that 
rotundity and compaftnefs fo remarkable in the edifices of that 
little architect. Again, the regular nell of the houfe-martin is 
hemifpheric ; 
