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191 



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, tinues for the space of a fortnight. On that occasion, 

 ludjoe. a u t [je tradesmen in the city are obliged to shift their 

 *""" ~"" * shops, and to erect booths In the t'nir, resembling 

 those of England, which are regularly arranged like 

 streets and thus afford a full view of the merchandise 

 of the place. There are caps from Trieste. Leghorn, 

 and Genoa; knives, sword-blades, gun-barrels, glass, 

 and paper from Venice ; some coffee and sugar from 

 Trieste; gold and silver thread from Vienna. But the 

 chief articles of importation are French and German 

 cloths from Lcipsic, which are purchased by all the 

 richer Greeks and Turks of the neighbouring countries 

 for winter robes and pelisse". English cloth is the 

 moat esteemed, but is seldom met with, on account of 

 it* high price ; and the best of what is sold at the fair 

 of Joannina, is not equal to the worst of English fabric. 

 The article* of exportation are oil, wool, corn, and to- 

 bacco for Naples, and the ports of the Adriatic ; spun 

 cottons for the plains of Triccola ; stocks of guns and 

 pistols, embroidered velvet*, stuffs, and cloths, for the 

 inland consumption of Albania and Romelia. Large 

 nocks of sheep and goats, and drove* of cattle and 

 horses, from the hiUs of Albania, are collected also at 

 this fair, and told for the Ionian Islands. The balance 

 of trade is in favour of Joannina, and is paid in Vene- 

 tian sequins. See Hobbouse's Tour in Albania, and 

 Holland's Travels in Greece, (y) 



IODINE. This word is of Greek etymology, and 

 Mgnifiei a tit>iet colour. It ha* been recently intro- 

 duced into the French and English language*, for 

 the purpose of being applied a* a name for a chemical 

 recently discovered. The description of that 

 its properties will now hold a prorr.i- 

 ; place in all system* of chemistry ; but it ie one 

 i which the science has been enriched since our ar- 

 ticle Chemistry was published. What applications it 

 may admit of in the useful arts we do not as yet know ; 

 but those propertiei which it has been found to pos- 

 ses* render it ulneaiilj interesting to chemistry a* m 

 v affording scope for experimental iimstig*) 

 .j ;_.: : and it so happens that it 



give* an additional importance, by it* curious analogic*, 

 to some of those dmtiine* which nave been in modern 

 time* most keenly contested, and in which the contend, 

 ing parties, with all the advantage* of pebent iiijiiiiiasajl 

 end consuuMnate acumen, aideflby the seal which a cer- 

 tain degree of opposition of opinion rxcrtw, have scarce- 

 ly been able to devise experiments of a decisive kind. 



The discoverer of iodine we* M. Courtois, a manu- 

 facturer of nitre in Paris, whose attention was direct- 

 ed to the subject, in consequence of a corrosion to 

 which the metallic vessel* employed in the process for 

 procuring soda from the ashes of sea- weeds were liable, 

 tne cause ot wnscn he investigated, and in the mvceti- 

 getion discovered Ibis svbstsnce- The leading investi- 

 gator* of Ha chemical propenie* have been M. Gay- Los- 

 sac and Sir Humphry Davy ; both of whom have ming- 

 led their experimental inquiries with their view* of the 

 more recondite laws of chemical change. In the pre- 

 sent article, it is our intenti.m to give a plain and per- 

 spicuous account of the- (ceding facta, without omit- 

 tmg to notice the most important and least intricate of 

 the argument* connected with them. 



M. Courtoi* discovered iodine in the year 1811 ; and 

 the discovery was announced to the Institute by M. 

 ( lemcat about two years after, vis on the 29th of No- 

 vember 1819. The chief reason of this long delay 

 term* to have been, that these two gentlemen had 

 wihed_to ascertain previously the qualities of this 'new 

 Mbttance, but had been prevented by the attention 



which their other pursuits demanded, from executing 

 their design so speedily or so extensively as they hoped. 



This substance is procured from kelp in the follow- 

 ing manner. The kelp is treated with hot water till all obuining it. 

 its soluble parts are dissolved. The solution is then 

 evaporated, and from the dry salt the substance in 

 question is separated by sulphuric acid. The salt is put 

 in a tubulated retort, deep, but not large. The beak of 

 the retort, which ought to be short, is introduced into 

 a large globular glass receiver, which has an opening 

 to allow the air to escape. Concentrated sulphuric acid 

 is poured on the salt, through the opening, which is then 

 closed with a stopper. An active effervescence ensue*, 

 and a violet-coloured gas is driven off, which crystallizes 

 on the inside of the receiver. This is the iodine. When 

 raised to its vaporific point of temperature, it is a violet- 

 coloured gas. Below that point, it has the form of 

 brownish black shining plates. 



It was at first erroneously reported that the io- 

 dine waa obtained from the insoluble parts of kelp. It 

 cannot be obtained from pounded kelp. The solution 

 and crystallization seem to be indispensable pre-requi- 

 sites to the operation. 



The following method, recommended by Dr. Wollas- 

 ton, yields it more abundantly. After concentrating the 

 aqueous solution of the soluble parts of kelp, and sepa- 

 rating from it all the crystals that can be obtained, the 

 remaining liquid is to be poured into a clean vessel, and 

 mixed with an exceas of sulphuric acid. This is boiled 

 for tome time, during which process sulphur is precipi- 

 tated, and muriatic acid is driven off. The clear liquid 

 i* then decanted off, and strained through wool. It is 

 next put into a small flask, with a quantity of black oxide 

 of inangmeeil. equal to that of the sulphuric acid first 

 employed. A giaa* tube, closed at one end, is fixed to 

 the top of the ruuk, and heat applied to the bottom. 

 The iodine is sublimed and crystallized within the tulu . 

 Soaper** black ashes yield it in large quantity. 



This substance has all the interest of a newly disco- 

 vered gas, and derive* a further interest from being 

 the second coloured gas known in chemistry ; colour 

 being a ptutietty po*ae**ed by none previously known, 

 excepting the oxvmuriatic or chlorine gas. A volume 

 of it of considerable diameter exhibit* a beautiful and 

 rich violet appearance. 



In the wild state, it ha* the form of flat octahedral nncrip- 

 crjrstala, the axe* of which are in the proportion of two, tion | |U 

 three, and four. The form which most frequently ap- cr 

 pear* in a aection parallel to the plane of the greatest 

 end fsnalleat axis, is a rhombic plate, bevelled at each 

 of its edge* by two narrow planes, inclined to one 

 another at an angle of about 1 20. 



According to the experiment* of Dr. Brewster, io- 

 dine peaesaaes the property of polarizing, in two op- 

 posite plane*, the light which it reflects, a property 

 which ii peculiar to metallic bodies. 



Its fusing temperature, when pure, is 225, and it is GtncnJ 

 volatilised at 347 or 356; though it may be distilled propertiis. 

 over with water at 12*. Its odour resembles that of 

 oxymuriatic gas, though weaker. It is soft and friable, 

 and may be rubbed into a fine powder. Its taste i 

 acrid, and it* action on the stomach poisonous. ' It 

 gives a deep brown stain to the skin, which, however, 

 is toon removed. Like the oxymuriatic acid, it de- 

 stroys vegetable colour*, though with less energy. It 

 i* soluble hi 4000 time* it* weight of water, and com- 

 municates to it an orange-yellow colour. Its specific 

 gravity at 2J is 4.9 W. 



Iodine is not combustible, and c-inrot he made to 

 combine, by any direct method, with oxygen. 



