ISINGLASS. 
but the sounds of all fresh water fish yield, 
more or less, fine isinglass, particularly the 
smaller sorts, found in prodigious quantities 
in the Caspian sea, and several Jiundred 
miles beyond Astracan, in the Wolga, Yaik, 
Don, and even as far as Siberia, where it is 
called kle or kla by the natives, which im- 
plies a glutinous matter; it is the basis of the 
Russian glue, which is preferred to all other 
kinds for its strength. The sounds, which 
yield the finer isinglass, consist of parallel 
fibres, and are easily rent longitudinally ; 
but the ordinary sorts are found composed 
of double membranes, whose fibres cross 
each other obliquely, resembling the coats 
of a bladder ; hence the former are more 
readily pervaded and divided with subacid 
liquors ; but the latter, through a peculiar 
kind of interwoven texture, are with great 
difficulty torn asunder, and long resist the 
power of the same menstruum ; yet, when 
duly resolved, are found to act with equal 
energy in clarifying liquors. 
Isinglass receives its dilferent shapes in 
the following manner. The parts of which 
it is composed, particularly the sounds, are 
taken from tlie fish while sweet and fresh, 
slit open, washed from their slimy sordes, 
divested of every thin membrane which 
envelopes the sound, and then exposed to 
s,tifren a little in the air. In this state, they 
are formed into rolls about the thickness ot 
a finger, and in length according to the in- 
tended size of the staple : a thin membrane 
is generally selected lor the centre of the 
roll, round which the rest are folded alter- 
nately, and about half an inch of each ex- 
tremity of the roll is turned inwards. The 
due dimensions being thus obtained, the 
two ends of what is called short staple are 
pinned together with a small wooden peg ; 
the middle of the roll is then pressed a little 
downwards, which gives it the resemblance 
of a heart-shape, and thus it is laid on 
boards, or hung up in the air to dry. 
The sounds, which compose the long- 
staple, are longer than the former ; but the 
operator lengthens this sort at pleasure, by 
interfolding the ends of one or more pieces 
of the sound with each other, The extre- 
mities are fastened with a peg, like the for- 
mer ; but the middle part of the roll is bent 
more considerably downwards, and, in 'orr 
der to preserve the shape of the three ob- 
tuse angles thus formed, a piece of round 
stick, about a quarter of an inch diameter, 
is fastened in each angle with small wooden 
pegs, in the same manner as the ends. In 
this state, it is permitted to diy long enough 
to retain its form, when the pegs and sticks 
are taken out, and the drying completed ; 
lastly, the pieces of isinglass are colligated 
in rows, by running pack-thread through 
the peg-holes, for convenience of package 
and exportation. That called cake-isin- 
glass is formed of the bits and fragments of 
the staple-sorts, put into a flat metalline 
pan, with a veiy little water, and heated 
just enough to make the parts cohere like a 
pancake when it is dried ; but frequently it 
is overheated, and such pieces, as before 
observed, are useless in the business of 
fining. Experieitce has taught the con- 
sumers to reject them. 
Isinglass is best made in the summer, as 
frost gives it a disagreeable colour, de- 
prives it of weight, and impairs its gelatinous 
principles ; its fashionable forms are unne- 
cessary, and frequently injurious to its na- 
tive qualities. It is common to find oily 
putrid matter, and exuvim of insects, be- 
tween the implicated membranes, which, 
through the inattention of the ceiiarman, 
often contaminate wines and malt liquors in 
the act of clarification. 
These peculiar shapes might probably be 
introduced originally with a view to conceal 
and disguise the' real substance of isinglass, 
and preserve the monopoly ; but, as the 
mask is now taken off, it cannot be doubted 
to answer every purpose more effectually 
in its native state, without any subsequent 
manufacture whatever, especially to the 
principal consumers, who hence will be 
enabled to procure sufficient supply from 
the British colonies. Until tins laudable 
end can be fully accomplished, and as a 
species of isinglass, more easily produceable 
from the marine fisheries, may probably bo 
more immediately encouraged, it may be 
manufactured as follows. The sounds of 
cod and ling bear great analogy with those 
of the accipenser genus of Linnasus and 
Artedi ; and are in general so well known 
as to require no particular description. The 
Newfoundland and Iceland fishermen split 
open the fish as soon as taken, and throw the 
back bones with the sounds annexed, in a 
heap ; but previously to incipient putrefac- 
tion, the sounds are cut out, washed from 
their slimes, and salted for use. In cutting 
out the sounds, the intercostal parts are left 
behind, which are much the best; the Ice- 
land fishermen are so sensible of this, that 
they beat the bone upon a block with a 
thick stick, till the pockets, as they term 
them, come out easily, and thus preserve 
the sound entire. If the sounds have been 
