2 best's art of angling. 



The centre of gravity is placed in die fittest 

 part of tiie body for swimming, and their shape 

 most commodious for making way through the 

 \vater, and most a^q;ieeable to geometrical rules. 



They liave several parts peculiar to them- 

 selves; as fins, to balance and keep them up- 

 right ; an air bladder, or swim, to enable them 

 to rise or sink to any height or depth of water, 

 at pleasure; gills, or branchiae, whereby they 

 respire, as land animals do by lungs ; the tail, an 

 instrument of progressive motion, which serves 

 to row them forward; eyes peculiarly formed to 

 enable them to correspond to all the convergen- 

 cies and divergencies of rays, which the varia- 

 tions of the watery medium, and the refractions 

 thereof may occasion ; in which respect they 

 bear a near resemblance to birds. 



In most fish, beside the great fin tail, we and 

 two pair of fins upon the sides, two single fins 

 on the back, and one upon the belly, or rather 

 between the bellv and the tail. The halancinc^ 

 use of these organs is proved in this manner : Of 

 the large headed fishes, if you cut off the pecto- 

 tal fins, i. e. the pair which lie close behind the 

 gills, the liead falls prone to the bottom : if the 

 right pectoral fin only be cut ofi", the fish leans 

 to that side ; if the ventral fin on the same side 

 be cut aw^ay, then it loses its equilibrium en- 

 tirely : if the dorsal and ventral fins be cut off, the 

 fish reels to the right and left. When the fish 

 dies, that is, when the fins cease to play, the belly 

 turns upwards. The use of the same parts for 

 motion is seen from the following observation 

 upon them when put in action. The pectoral 

 and more particularly the ventral fins, serve to 

 raise and depress the fish : when the fish desires 

 to have a retrograde motion, a stroke forward 



