1SI 



ISI 



It beat's a great resemblance to iron 

 sand in colour, but in specific gravity it 

 differs, as also in its being 1 very slightly 

 attractable by a powerful magnet. It is 

 found on high mountains in Germany. 



1SERT1A, in botany, a genus of the 

 Hexandria Monogynia class and order. 

 Essential character : calyx coloured, four 

 or six-toothed ; corolla six-cleft, funnel 

 form ; pome sub -globular, six celled, many 

 seeded. There is but one species, viz. I. 

 coccinea, a tree with a trunk ten ortwelve 

 feet in height, and about eight inches in 

 diameter ; the bark is wrinkled, and of a 

 russet colour ; the wood light, and of a 

 loose texture ; branches quadrangular, 

 straight, with opposite branchlets, chan- 

 nelled and covered with a russet down ; 

 each branchlet has three flowers, of which 

 that in the middle is sessile ; calyx pur- 

 plish ; tube of the corolla two inches long 

 of a bright red; border yellow, covered 

 on the inside with hairs of the same 

 colour; fruit a succulent red berry or 

 pome, the size of a cherry, sweet and good 

 to eat. The wood is bitter ; a decoction 

 of leaves is used by the Creoles in fomen- 

 tations. It is common in the island of 

 Cayenne, and on the continent of Guia- 

 na, flowering and bearing fruit a great 

 part of the year. 



ISINGLASS, used in medicine and do- 

 mestic economy, is a preparation formerly 

 made only from a fish named huso, a spe- 

 cies of the Accipenser genus. We have, in 

 the sixty-third volume of the transactions 

 of the Royal Society, a full account of the 

 mode of preparing this substance, of 

 which we shall give an extract. 



The sounds, or air-bladders, of fresh 

 water fish in general, are preferred for 

 this purpose, as being the most transpa- 

 rent, flexible, delicate substances. These 

 constitute the finest sorts of isinglass ; 

 those called book and ordinary staple are 

 made of the intestines, and probably of 

 the peritoneum of the fish. The belluga 

 yields the greatest quantity, as being the 

 largest and most plentiful fish in the Mus- 

 covy rivers ; but the sounds of all fresh 

 water fish yield, more or less, fine isin- 

 glass, particularly the smaller sorts, found 

 in prodigious quantities in the Caspian 

 sea, and several hundred miles beyond 

 Astracan, in the Wolga, Yaik, Don, and 

 even ar far as Siberia, where it is called 

 kle or kla by the natives, which implies 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 re^ longitu- 

 dinally ; but the ordinary sorts are found 



composed of double membranes, whose 

 fibres cross each other obliquely, resem- 

 bling 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 inter- 

 woven 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 differentshapes in 

 the following manner. The parts of whick 

 it is composed, particularly the sounds, 

 are taken from the fish while sweet and 

 fresh, slit open, washed from their slimy 

 sordes, divested of every thin membrane 

 which envelops the sound, and then ex- 

 posed to stifte'n a little in the air. In this 

 state, they are formed into rolls about 

 the thickness of a finger, and in length 

 according to the intended size of the 

 staple : a thin membrane is generally se- 

 lected for the centre of the roll, round 

 which the rest are folded alternately, and 

 about half an inch of each extremity of 

 the roll is turned inwards. The due di- 

 mensions 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 press- 

 ed 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 plea- 

 sure, by interfolding the ends of one or 

 more pieces of the sound with each other. 

 The extremities are fastened with a peg 1 , 

 like the former ; but the middle part of 

 the roll is bent more considerably down- 

 wards, and, in order to preserve the shape 

 of the three obtuse angles thus formed, a 

 piece of round stick, about a quarter of 

 an inch diameter, is fastened in each an- 

 gle with small wooden pegs, in the same 

 manner as the ends. In this state, it is 

 permitted to dry 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-isinglass, 

 is formed ^fthe bits and fragments of the 

 staple-sorts, put into a flat metalline pan, 

 with a very 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 be- 

 fore observed, are useless in the business 



