F i S 
The number of Fiflies with whofe names and 
figures we are in fome meafure acquainted, fome- 
what exceeds four hundred. Thus, to appearance 
indeed, the hiftory of this clafs of nature is tole- 
rably copious; but when we come to a more mi- 
nute enquiry, it will be found, that of the greateft 
part of the(e v/e knov/ but few qualities. Moft 
Fifhes prefent the fame external form, fharp at 
cither end, and fwelling in the middle ; which fi- 
gure enables them with greater celerity and eafe 
to traverfe the fluid they are deftined to inhabit. 
That peculiar fhape v/hich nature has given to 
moft Fiflies, human art has endeavoured to imi- 
tate in fuch veflels as are defigned to fail with the 
greateft fwiftnefs; but the progrefs of fuch ma- 
chines is infignificant when compared to the rapi- 
dity of thefe animals. Any of the larger kind of 
Fiflies overtake a fliip in full fail with great eafe, 
play round it v/ithout effort, and outftrip it at 
pleafure. All parts of their bodies feem adapted 
to accelerate their motion; their fins, their tails, 
and the undulation of their back-bones, affifc pro- 
greffion ; and it is to that flexibility of body which 
art can never give, that Fifties owe their fuperior 
velocity. 
The fins are the chief inftruments of motion in 
thefe animals; and tliofe in fome of them are more 
numerous than in others. A Fifti, compleatly 
equipped for lailing, is furniftied with two pairs, 
and three fingle fins, two above and one below. 
Thus qualified, it moves with the utmoft rapidity, 
and undertakes voyages of a ihoufand leagues in 
a feafon. Thofe Fiflies, hov/ever, that have the 
greateft number of fins, are not always the fwifteft: 
the ftiark is efteemed one of the inoft aftive fwim- 
mers, yet it wants the ventral, or belly-fins ; and 
the haddock, which it always outftrips, is com- 
pleatly fitted for motion. 
Befides affifting the Fifn in it's progreflion, the 
fins are neceffaiy in rifing or finking, in turning, or 
even leaping out of the water. The perioral fins, 
like oars, ferve to pufli the creature forward : thefe 
are placed at fome diftance behind the opening of 
the gills; and are generally large and ftrong, an- 
fwering the fame purpofes to a Fifli in the water, 
that wings do to a bird in the air. By the conti- 
nued miotlon of thefe fins, the Flying-Fifli fome- 
times rifes cat of the water, and fiies above an hun- 
dred yards, till, wearied with it's exertions, it drops 
' again into it's native element. The peftoral fins 
ferve aifo to balance the liead of the Fiih, when 
too large for the body, and to keep it from falling 
prone to the bottom; as is the cafe with large- 
iieaded Ftfli, when the peftorai fins are removed. 
The ventral fins are placed under the belly, to- 
wards the lower part of the body; and, whatever 
may be tlie fiiuation of the Fifli, thefe are always 
feen flat on the water, and rather to raife or de- 
prefs the animal than to forward it's progreffive 
motion. The dorfal fin is fituated along; the rid":e 
of the back; and not only keeps the Fifti in equi- 
iibrio, but alfo afiifts it's velocity. Many Fiflies, 
indeed, are deftitute of this appendage; but it is 
very large in all fiat Fifti, the perioral fins of which 
lire proportionably fmaller. The anal fin occu- 
pies that part of the creature which lies between 
the anus and the tail, and this fervcs to keep the 
Fifli in it's upright or vertical fituation. But the 
tail, v/hich in fome Fiflies is horizontal, and in 
others perpendicular, feemis to be the grand inftru- 
ment of m-otion ; the fins being all fubfervient to 
it_, and only giving diredion to it's powerful im- 
FIS 
petus, by which the Fifii feems to dart forwards 
with fo great velocity. 
If any Fifii is put into a large vefl^el filled with 
water, thefe pofitions will be eafily illuftratedi 
The animal, in a ftate of repofr, fpreads all it's 
fins, and feems to reft on it's pe6loral and ventral 
fins near the bottom. If the Fifli folds up either 
of it's perioral fins, (a faculty which it pofl^effes) 
it immediately inclines to the fame fide; when ic 
is defirous of a retrograde motion, ftriking with 
the peftoral fins in a contrary direcftion effeftually 
produces it; and when it defires to turn, a blow 
from the tail fends it about; but if the tail ftrikes 
both ways, then the motion is progreffive. In 
purfuance of thefe obfervations, if the dorfal and 
ventral fins be cut off^, the Fifli reels to the right 
and left, and endeavours to fupply it's lofs by 
keeping the reft of it's fins in unceafing aftion. 
If the right peftoral fin be amputated, the animal 
inclines to that fi.de; if the ventral fin on the fame 
fide be removed, then it lofes it's equilibrium en- 
tirely; but when the tail is cut off\, the Fifli lofes 
all motion, and yields itfelf to the impulle of the 
water. 
Flence it appears, that each of thofe inftruments 
has a peculiar ufe affigned it; but, at the fame 
time, that they all confpire to aflift each other's 
motions. It is certain, however, that the number, 
the fize, and the fituation of the fins, feem rather 
to correfpond with the animal's figure, than en- 
tirely to an Twer the purpofes of promoting it's 
fpeed. If the head of the Fifli is large and heavy, 
the peftoral fins are alfo large, and placed for- 
wards, to preveat it's overfetting; but if the head 
is fmall, fliarp-pointed, and not too heavy for the 
tail, the peftoral fins are likewife fmall, and the 
Fifli is totally deftitute of the ventral. 
As terraqueous animals are generally furniflied 
with coverings to keep off' the injuries of the wea- 
ther, fo the inhabitants of the water are covered 
with a flimy glutinous matter, Vvhich, like a flieath, 
defends their bodies from the immediate contaft 
of the furrounding fluid, and alllfts them in their 
eafy progrefs through the water. Beneath this, 
in many kinds, is found a ftrong covering of 
fcales, which, like a coat of mail, proves a moft pow- 
erful defence; and under that, before we com.e to 
the mufcular parts of the body, an oily fubftance is 
lodged, which fupplies the requifite warmth and 
vigour. 
Thus protected, and fitted for motion in it's 
native element, the Fifli feems as well furniflied 
with the means of happinefs as quadrupeds or 
birds; but if v/e more accurately infpcd: it's facul- 
ties, we fliall find it much their inferior. The 
fenfe of touching, which birds and bcaft"s in fome 
degree enjoy, can be but very imperfectly felt by 
the Fiili, wrapped up in it's own coat of mail. 
The fenfe of fmelling, indeed, fo exquifite among 
beafts, and a little known among birds, is imparted 
to Fifties but in a very limited degree. It is true, 
that all Fillies have one or more noftrils ; and even 
thofe which have not the apertures perceptible 
without, have notwithftanding the propei- olfa£lory 
nerves within. But as air is the only known me- 
dium for the diftribution of odours, it cannot be 
fuppofed that thefe animals, refiding in water, can 
poftels any power of being aftefted by them. If 
they have any perception of fmells, it muft be in 
the fame manner in v/hich the human fpecies diftin- 
guifti by their taftes; and it is probable that the 
olfaftory membrane in Fiflies fupplies the place of 
a difcriminating 
