2?0 A HISTORY OF 



ity. It must displease him to see the language of a science increas- 

 ing, while the science itself has nothing to repay the increasing tax 

 laid upon his memory. 



Most fish offer us the same external form, sharp at either end, and 

 swelling in the midd.e ; by which they are enabled to traverse the 

 *luid which they inhabit, with greater celeritv and ease. That pecu 

 'iar shape which Nature has granted to most fishes, we endeavour to 

 imitate in such vessels as are designed to sail with the greatest swift- 

 ness ; however, the progress of a machine moved forward in the water 

 by human contrivance, is nothing to the rapidity of an animal destined 

 by Nature to reside there. Any of the large fish overtake a ship in 

 full sail with great ease, play round it without effort, and outstrip it at 

 pleasure. Every part of the body seems exerted in this despatch ; the 

 fins, the tail, and the motion of the whole back-bone, assist progres- 

 sion ; and it is to that flexibility of body at which art cannot arrive, 

 that fishes owe thair great velocity. 



The chief instruments in a fish's motion, are the fins ; which, in 

 some fish, are much more numerous than in others. A fish com- 

 pletely fitted for sailing, is furnished with no less than two pair ; also 

 three single fins, two above and one below. Thus equipped, it mi- 

 grates with the utmost rapidity, and takes voyages of a thousand 

 leagues in a season. But it does not always happen that such fish as 

 have the greatest number of fins have the swiftest motion : the shark 

 is thought to be one of the swiftest swimmers, yet it wants the ventral 

 or belly fins ; the haddock does not move so swift, yet it is completely 

 litied for motion. 



But the fins serve not only to assist the animal in progression, but 

 in rising or sinking ; in turning, or even leaping out of the vvatei 

 To answer these purposes, the pectoral fins serve, like oars, to pusn 

 the animal forward; they are placed at some little distance behind 

 the opening of tue gills ; they are generally large and strong, and 

 answer the same purposes to the fish in the water, as wings do to a 

 bird in the air. With the help of these, and by their continued mo- 

 tion, the flying-fioh is sometimes seen to rise out of the water, and to 

 fly above a hundred yards; till, fatigued with its exertions, it is 

 obliged to sink down again. These also serve to balance the fish's 

 head, when it is too large for the body, and keep it from tumbling 

 prone to the bottom, as is seen in large-headed fishes, when the pec- 

 toral fins are cut off. Next these are seen the ventral fins, placed 

 towards the lower part of the body, under the belly ; these are always 

 seen to lie flat on the water, in whatever situation the fish may be ; 

 and they serve rather to depress the fish in its element, than to assist 

 progressive motion. The dorsal fin is situated along the ridge of the 

 back and serves to keep it in equilibrio, as also to assist its progres- 

 sive motion. In many fishes this is wanting ; but in all flat fishes it 

 is very large, as the pectoral fins are proportionably small. The anal 

 r m occupies that part of he fish which lies between the anus and the 

 tail ; and this serves to keep the fish in its upright or vertical situa- 

 tion. Lastly the tail, which in some fishes is flat, and upright in 

 other?, seems the grand instrument of motion : the fins are but all 

 subservient to it, and give direction to its great impetus, by which 

 t'ie ash seems to dart forward with so much velocity. To explain all 



