THE WHALE. 121 



elevate in no inconsiderable degree, our concep- 

 tions of the Great Supreme. The mysticetus feeds 

 on the smallest insects; its capacious mouth, with 

 the vast fringes of whalebone, which is a most ad- 

 mirable filter, enables it to receive some tons of 

 water at a mouthful, and to separate every substance 

 from it, of the size of a pin's head and upwards. 

 The physalis feeds on herrings, mackarel and other 

 fishes of a similar kind; its whalebone therefore is 

 shorter, stronger, and less compact than that of the 

 mysticetus, and the filter formed by it less perfect. 



As the whale must rise to the surface of the sea 

 to breathe, its tail is placed horizontally, to enable 

 it to ascend and descend more quickly; and its nos- 

 trils, or blowholes, instead of being placed at the 

 snout, are generally on the most elevated part of 

 the head, that they may be readily lifted clear of 

 the water. 



When the whale descends to the depths of the 

 ocean, it becomes exposed to an enormous pressure 

 from the superincumbent water. This pressure is 

 sufficient to force the water through the pores of the 

 hardest wood; yet it is effectually resisted by the 

 skin of the whale, though it is remarkably soft and 

 flexible. To exclude the water from the lungs, 

 which would occasion suffocation if admitted, the 

 blowholes are defended by the peculiar valves that 

 have been already described. 



The variety discovered in the structure of whales, 

 is by no means one of the least interesting parts of 



Vol. III. 16 



