^4 THE PHILOSOPHY 



of form. None of the other clafles have more legs than four. 

 But mofl infeds have fix ; and many of them have eight, ten, 

 fourteen, fixteen, eighteen, and even a hundred, legs. Befide 

 the number of legs, infeds are furnifhed v?ith antennae or feelers. 

 Thefe feelers, by which infedts grope and examine the fubftances 

 they meet with, are compofed of a great number of articulations or 

 joints. Linnaeus, and other Naturalifts, maintain, tiiat the ufes 

 of thefe feelers are totally unknown. But the flighteft attention 

 to the manner in which fome infeds employ their feelers will 

 fatisfy us of at leaft one uie they derive from thefe organs. When 

 a winglefs infe£t is placed at the end of a twig, or in any fituation 

 where it meets with a vacuity, it moves the feelers backward and 

 forward, elevates, deprefles, and bends them from fide to fide, and 

 will not advance farther, left it fhould fall. Place a ftick, or any 

 other fubftance, within reach of the feelers; the animal immediate- 

 ly applies them to this new objed, examines whether it is fufficient 

 to fupport the weight of its body, and inftantly proceeds in its jour- 

 ney. Though moft infeds are provided with eyes, yet the lenfes of 

 •which they confift are fo fmall and convex, that they can fee di- 

 ftindly but at fmall diftances, and, of courfe, muft be very incom- 

 petent judges of the vicinity or remotenefs of objeds. To remedy 

 this defed, infeds are provided with feelers, which are perpetually 

 in motion while the animals walk. By the fame inftruments, they 

 are enabled to walk with fafeiy in the dark. 



No other animals but the infed tribes have more than two eyes. 

 Some of them have four, as the phalangium ; others, as the fpider 

 and fcorpion, have eight eyes. In a few infeds, the eyes are fmooth; 

 in all the others, they are hemifpherical, and confift of many thou- 

 fand diftind lenfes. The eyes are abfolutely immoveable : But this 

 defed is fupplied by the vaft number of lenfes, which, from the di- 

 verfity of their pofitions, are capable of viewing objeds in every di- 



redion. 



