ICHTHYOLOGY. 
734 
at all depths, neither Impedes them by its rarity nor by 
its temperature. They penetrate its abyfs unfathomable 
by men; they ruffle its very furface; and they find their 
food almolt at every point between. 
Certain winds promote, retard, flop, or change the di¬ 
rection of, the journeys of birds.—Certain currents of wa¬ 
ter accelerate, diminifh, fufpend, or change, the varied 
courfe of the inhabitants of the leas. 
Thofe birds only, whofe ftrength of wing has gained 
them the name of great failors, but which might rather be 
called gfoat rovers, can refill the violent motions of the 
atmofphSre, brave the tempeft, and oppofe the unchained 
winds.—Thofe filhes only, whofe broad fins, large tail, 
and ftrong mufcles, entitle them to the name of fwimmers 
or rowers in particular,are able to refill the oppofing waves, 
brave the florm, and boldly purfue their courfe through 
thofe dreadful commotions which feem to harrow up the 
•yery depths of the ocean. 
Birds, weak and ill-provided for defence, tremble at 
the formidable bill and cruel claws of the tyrants of the 
air.—Fifhes of a fmall fize and unarmed, continually flee 
from the bloody teeth of the fhark and other rapacious 
animals which infeil the rivers and feas. 
From the furface of the earth, over which the bird has 
its airy, abode, the bird often receives death from the 
hand of the fportfman, or from fnares which its inftinft 
cannot always avoid.—In the midfl of his aquatic empire. 
She fifh periihes by the treacherous bait, or lingers a Ihort 
time in the fifherman’s net. 
The neceflity of feeking proper food, or of efcaping a 
dangerous enemy, occafions irregular journeys or migra¬ 
tions in birds.—The neceflity of avoiding the fight or 
fmell of the ferocious tyrants of the fea, or of appeafing 
hunger fifill more cruel, produces the irregular journeys 
of fifhes. 
When the winter feafon approaches in the temperate 
countries, and efpecially in thofe parts nearefl the polar 
circle, birds begin their regular or periodical migrations. 
They can no longer remain where the earth is covered 
with fnow; where the furface of the water is crufled with 
ace; where the infefts die, or conceal themfelves ; where 
the fields are flripped of grain, and the trees of fruit: they 
depart therefore; approaching the tropics, they feek a 
milder, a happier, dwelling; all-bountiful Providence di¬ 
rects their courfe. They follow the direflion of the me¬ 
ridians ; they traverfe cor.fequently large continents. They 
unite in numerous flocks ; males and females, young and 
old, collected without diftinftion of fex or age, fly from 
the empire of frofl to enjoy the fun’s rays in another 
country, till 1 'uCh time as the fame mild reign is reftored 
an their own. Then they return in the fame order and 
by the fame route.—The diverfity of feafons does not 
feem to produce fuch confiderable changes in the tempe¬ 
rature of the different parts of the ocean, as to force fifhes 
to a regular annual emigration ; but the defire of repro¬ 
duction, which is always performed near the fhores,. im- 
pe's them, at the return of fpring, to quit the main ocean, 
and repair to the banks and fhallows. They do not pro¬ 
ceed in the direction of the meridian; but, according to 
the pofition of continents in the midfl of the main ocean, 
they moftly endeavour to trace one of the parallels of the 
globe, to arrive more eafily and quickly at the lands whofe 
"borders are to receive their eggs or milt. The females 
arrive firlt, being more eager to get rid of their load which 
as greater; the males follow. Ivloll commonly they fol¬ 
low the fame parallels when they afcend the llreams and 
great rivers, and when they return; becaufe, with the ex¬ 
ception of the Mifliffippi, .of fome rivers in Terra Firma 
in America, of the Rhone, the Nile, the Bbryfthenes, the 
Don, the Volga, the Sindus, the Ava, the river of Cam- 
bogia, and fome others, rivers run from eaft to welt, or 
from welt to eaft. 
The birds which inhabit large continents are the mod- 
numerous; fo are the fifhes in thofe parts which contain 
a 
the mod extenfive banks. It Is not -forprifing, therefore, 
that there are more birds in the northern hemifphere than 
in the fouthern, on account of the greater quantity ofT 
land it contains; nor that we fliould find more fifh-in the-- 
fame northern hemifphere, becaufe, though the finny tribe 
have greater fpace in the fouthern half, on account of the 
vafl feas it contains, and the fmall number of continents 
and iflands, there are but few fhores where the fifhes can 
depofit their fpawn ; ' fpace is not wanting for the indivi¬ 
duals, but banks are wanting for the fpecies. 
If, with feveral naturalifts, we admit that the waters 
in former ages were higher than at prefent, and covered 
parts of the prefent continents, fo as to divide them into 
a great number of iflands, though without much dirifi- 
nifhing their total furface, we may alfo luppofe, from the 
preceding obfervations, that there were at that time much 
fewer birds than at prefent, and more fifh', becaufe every 
divifion made in the land by the fea neceffarily increafed 
the number of places convenient for the reproduction and 
multiplication of fifhes. 
Ichthyology has hitherto been but little fludied in 
England; the reafon of which is owing to our want of 
books on that fubjeft. Many fifhes well known in one 
country were perhaps never heard of in another; even 
thofe fpecies found in Saxony, Silefia, Pomerania, Pruflia, 
and Germany, are not all defcribed by the great Linnaeus; 
in Linnaeus alfo, the del'criptions are often fo fhort as to 
be by no means clear; and the accounts in Artedius- are 
often unfatisfaClory, becaufe he confounds the names, and 
becaufe his drawings are not faithful reprefentations of 1 
the fubjeCls he defcribes. 
In general it may be remarked, that the hiflory of fifhes 
has in our days been greatly neglected, while every other ■ 
part of natural hiflory has made a rapid progrefs; for, 
while books and authors have multiplied fo prodigioufly, 
how rarely do we met with any fatisfaftory treatife on the 
fubjeft of fifhes! Surpriling indeed is it to think that 
this branch of natural hiflory has been fo negleCted, 
Whole focieties have made the ftudy and management of 
bees their occupation ; and certainly fifh, which furnifh 
fuch abundant food, and have been at all times a confi¬ 
derable branch of commerce, deferve at lead as great a 
fliare of our attention. See the article Fishery, vol.-vii, 
p. 406. 
Bloch has enriched this branch of natural hiflory with 
accurate del’criptions and excellent coloured plates of a 
vafl number of new fpecies, and fome entirely new genera; 
and to his fplendid work we have been greatly indebted,. - 
as will be feen by a reference to our articles Cyfrinus, 
Gymnotus, See. As he confined his ftudies principally 
to this fubjeft, his accounts are far more accurate than 
thofe of any writer which preceded, even than the great - 
Linnaeus liimfelf, whofe vafl genius extended itfelf to fuch 
a multitude of objects. Bloch adhered to the Linnaean 
fyflem as much as poffible, introducing his own newly- 
difeovered fpecies and genera next to thofe they moft re- 
fembled. His deferiptions of the fifties of Germany, Pruf- 
fia, and Pomerania, are very valuable, as being made from 
the real fubiefls, and moftly on the fpot; and, having ah 
extenfive correfpondence in various parts of the world, 
he added many hitherto not at all known in Europe, and 
exceeding; in the brilliancy of their colours all that were 
known ; this was particularly the cafe with refpeft to the 
beautiful fpecimens tranfmitted to him by Mr. John-, mif- 
fionary at the Danifh fettlement at Traaquebar, on the 
Coromandel coaft. The difficulty of preferving and tranf- 
mitting fpecimens from thele regions is ftrikingly pour- 
irayed in a letter from that gentleman to Dr. Bloch, ex¬ 
tracts from which are inferted in the 10th part of his Ich- 
thy.ologie, as follows : “ Sir, A Danifh veflel brought me 
a iew days ago your letter, dated the 14th of November, 
1789. This veifel was leventeen months on her paflage. 
Being informed of the continuation of your work, I be¬ 
gan. to make collections for you upon a large fcale ; I 
employed : 
