where mosses and gossamer, and cotton from vege- 

 tables, are hardly to be found, the nest of the chaf- 

 finch 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 remark- 

 able in the edifices of that little architect. Again, 

 the regular nest of the house-martin is hemispheric ; 

 but where a rafter, or a joist, or a cornice, may hap- 

 pen to stand in the way, the nest is so contrived as 

 to conform to the obstruction, and becomes fiat or- 

 oval, or compressed. 



In the following instances instinct is perfectly 

 uniform and consistent. There are three creatures, 

 the squirrel, the field-mouse, and the bird called the 

 nut-hatch {Sitta Europcsa), which live much on hazel- 

 nuts ; and yet they open them each in a different 

 way. The first, after rasping off the small end, splits 

 the shell in two with his long fore-teeth, as a man 

 does with his knife ; the second nibbles a hole with 

 his teeth, as regular as if drilled with a wimble, and 

 yet so small that one would wonder how the kernel 

 can be extracted through it ; while the last picks an 

 irregular ragged hole with its bill : but as this artist 

 has no paws to hold the nut firm while he pierces it, 

 like an adroit workman, he fixes it, as it were in a 

 vice, in some cleft of a tree, or in some crevice : 

 when, standing over it, he perforates the stubborn 



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