154 HISTORY OF FISH. 



to appearance, the hiftory of fifh is tolerably copious; 

 but when we come to examine, it will be found that 

 of the greateft part of thefe we know very little. 

 Thofe qualities, Angularities, or advantages, that 

 render animals worth naming, ftill remain to be dif- 

 covered. 



Moft fifh offer us the fame external form ; iharp at 

 either end, and fwelling in the middle; by which 

 they are enabled to traverfe the fluid which they in- 

 inhabit with greater celerity and eafe. That pecu- 

 liar lhape which nature hath granted moft fifhes, we 

 endeavour to imitate in fuch veffels as are defigned 

 to fail with the greateft fwiftnefs ; however, the pro- 

 grefs of a machine moved forward in the water by 

 human contrivance, is nothing to the rapidity of an 

 animal defigned by nature to refide there. Any of 

 the large fifh overtake a fhip in full fail with great 

 eafe, play round it without effort, and outflrip it 

 with pleafure. Every part of the body feems ex- 

 erted in this difpatch ; the fins, the tail, and the 

 motion of the whole back-bone, affift progreffion ; 

 and it is to that flexibility of body, at which art can- 

 not arrive, that fifhes owe their great velocity. 



The chief inftruments in. a fifh's motion, are the 

 fins 5 which, in fome fifh, are much more numerous 

 than in others, A fifh completely fitted for failing, 

 is furnifhed with, at the leaft, two pair ; alfo three 

 fingle fins, two above and one below. Thus equipped, 

 it migrates with the utmoft rapidity, and takes voy- 

 ages of 1000 leagues in a feafon. But it does not 

 always happen that' fuch fifh as have the greateft 

 number of fins have the fwifteft motion ; the fhark is 

 thought to be one of the fwifteft fwimmers, yet it 

 wants the ventral or belly fins ; the haddock does 

 not move fo fwift, yet is completely fitted for 

 motion. 



But the fins ferve not only to affift the animal in 

 frogreffion, but in rifmg or finking, in turning, or 

 even leaping out of the water. To anfwer thefe 



purpofcsj 



