NATURALISTS CABINET. 



Rapid motion of fish. 



and swelling in the middle, by which configuration 

 they are enabled to traverse the watery element 

 with greater ease and swiftness. From their 

 shape jueu have taken the idea of those .vessels 

 which are intended to sail with the greatest 

 speed; but the progress of the swiftest sailing 

 ship, with the advantage of a favourable wind, 

 is far inferior to ihut of fish. Ten or twelve 

 miles an hour is no small degree of rapidity in 

 the sailing of a ship; yet any of the larger spe- 

 cies of the watery tribe would soon overtake her, 

 play round as if she did not move, and even ad- 

 vance, considerably before her. 



The motion of fish being different from that 

 of fowls or quadrupeds, they require neither an- 

 terior nor posterior extremities, but are provided 

 with machines, consisting of a number of elastic 

 beams, connected by firm, membranes, and with 

 a tail of the same texture. Their tails are so 

 framed as to contract to a narrow space when 

 dravrn together to either side, and to expand 

 when drawn to a straight line with their bodies: 

 thus, by the assistance of this broad tail, and I lie 

 fins on their sides, they make their progression 

 much in the same way as a boat with oars on its 

 sides, and a rudder at its stein. 



The fins of fish are denominated from their 

 situations. The pectoral fins are placed at a lit- 

 tle distance behind the opening of the gills, and 

 are large and strong, and serve as well to balance 

 the body as to assist the motion of the fish. The 



