NATURAL THEOLOGY. 



359 



mal itself be heavier than air, the thread which it 

 spins from its bowels is specifically lighter. This 

 is its balloon. The spider, left to itself, would 

 drop to the ground ; but being tied to its thread, 

 both are supported. \v . have here a very pecu- 

 liar provision; and to a contemplative eye it is a 

 gratifying spectacle to see this insect wafted on 

 her thread, sustained by a levity not her own, and 

 traversing regions which, if we examined only the 

 body of the animal, miglit seem to have been for- 

 bidden to its nature.'"" 



I must now crave the reader's permission to 

 introduce into this place, for want of a better, an 

 observation or two upon the tribe of animals, 

 whether belonging to land or water, which are 

 covered by shells. 



/-feiix o5juersa of Mailer, — common garden snail; but the cut 

 represents what is called a left- handed -shell, and a rarity. 



*•* It was at one time supposed that the spider could project its 

 iiatead through the air at will in any direction, and thus attaching 



