IRON. 



Tt blackers before the b'.ovv-pipe, and imparts an olive- 

 ^ecn colosr to borax. 



It is but rarely met with, and appears to be, in fome in- 

 ftances, of pfeudo-voicanic 'origin. Its occurrence with por- 

 celain jafper, and other minerals which are evidently of that 

 crafs, L'ives conlidcrable colour to the idea ; but there are 

 cafes, as the one obferved by Reufs in Bohemia, where it 

 appeared in tie centre of a mountain of clay-flate, that are 

 equ?.lly oppoiite in their evidence. 



It is found in the ifleof Arran, at Sobrufan, Hofchnitz, 

 Delau, and near Prohn, in Bohemia ; at Dutvveiler, in Saar- 

 ■briicken ; and Amberg, in the Upper Palatinate. 



It yields too fmall a proportion of metal, even where the 

 mineral is fufRcitntly abundant, to be at all worked as an ore 

 of iron. 



Subfp. 3 . I^enliailar Clay Ironjlone. — Colour brownifh-red, 

 varying to reddi;!! and yellowilh-brown, and greyidi-black. 

 Occurs maiTive. Interaally it is (Irongly glimmering, feme- 

 times g'liftening, and al.vays femi-metallic. Frafture fine 

 earthy, and fometimes flaty. Fragments indeterminate, 

 blunt-edged. Occurs in dillinft concretions, which are fre- 

 quently lenticu'ar, but fometimes granular. The ftreak 

 varies with the colour of the fpecimen : generally lighter. 

 It is ufually foft, fometimes very foft, and femi-hard. Sedlile, 

 inclining to brittle ; very eafily frangible, and heavy. 



Its compofition, according to Lampadius, is 

 Of oxyd of iron 64. 



Alamine - 23. 



Silex - - 7.5 



Water - - 5. 



Lofs 



The black varieties, which occur only in th? canton of 

 ■Berne, are faid to yield go per cent, of iron. The red ore, 

 which is found very abundantly in Bohemia, affords 60 per 

 rtnt. 



It is diftributed in tranfition and fletz mountains, and 

 generally unmixed with other minerals. 



Befides the fituations already noticed, it is met with in 

 Suabia, the Netherlands, Bavaria, Franconia, and France. 



It is fmelted as an ore of iron, and the brown varieties of 

 It, which contain from 30 to ^^ per cent, of metal, are much 

 valued on account of the excellent quahty of the metal that 

 is produced from them. 



Subfp. 4. Jafpery Clay Iron-Jlone. — Colour brownifh-red . 

 Occurs maflive. Internal luftre dul, bordering on glim- 

 mering. Frafture flat concboidal ; fometimes even. Frag- 

 ments rhomboidal, alfo cubic and trapezoidal. Lighter in 

 the ftreak. Soft, brittle, eafily frangible, and heavy. 



It has, hitherto, been only met with in a bed which be- 

 longs to the fecondary or fletz formation, between Vienna 

 and Hungary. 



Sublp.r. Common Clay Ironjlone. — Colourlight yellowilh- 

 grey, inclining to alh-grey, and pafling into blueilh and 

 ueel-grey, yellowilh, reddifh, and clove-brown, brick-red, 

 and brownifh-red. Thefe colours, particularly the lighter 

 ones, undergo a change on cxpofure to the air, generally 

 becoming darker. Occurs maftive, and in a variety of ex- 

 traneous forms, efpecially of (hells and vegetables. In- 

 ternally it is dull. Frafture earthy, fometimes conchoidal 

 and flaty. Fragments indeterminate, blunt-edged ; foft ; 

 rather brittle ; adheres a little to the tongue; is more or lefs 

 eafily frangible ; meagre to the touch, and heavy. Sp. gr. 

 from 2.936 to 3.471. 



Expoleti alone before the blow-pipe it-blackens, but does 



not melt. With borax it enters into a fort of ebullitioH, 

 and produces a glafs of a blackifh olive-green colour. It 

 varies confiderably in the proportion of its ingredients. 

 Some fpecimens of the mineral yield as much as 40 per cent. 

 of oxyd oi iron, whiHl others do not afford more than 20 

 pir cent., and many even lefs than that. Th?! following, 

 which will contribute to fliew this, are the refults cf fome 

 analyfcs by Richter and I^ampadius, 



Oxyd of iron 20.1 339 39. 42. J 



Oxyd of manganefe 1. 1. 1 3. 



Silex - - 19.9 23.9 5. 13.8 



Aluiiiine - 30.2 13. 40. I J. 6 



Magne.'ia - " 6. " 



Carbonic acid - 28.8 28.1 27.1 



Water - 9. 



Sulphur - ,. 



This fubfpecies is a very abundant ojje, and occurs in bcd« 

 in the fecondary cr fletz formation. 



It is found very plentifully in difFerent parts of England 

 and Scotland ; and is alfo met wjth in Weftphalia, Bohemia, 

 Silefia, the Upper Palatinate, Poland, RufTia, Siberia, 

 Ita'y, and Norway. 



Subfp. 6. Ren'tfarm Iron ore. — Colour yellowifh-brown, 

 varying in intenfity in the fame fpecimen. The centre is the 

 lighteft, and not unfrequently includes a fmall kernel of an 

 oclirc-yellow-tint. Occurs in mafTes from the fize of a wal- 

 nut to that of a man's head, which are moll commonly im- 

 bedded in clay or fhale. Fraftured towards the furface, 

 even ; in the interior fine earthy. Fragments indeter- 

 minate, rather Iharp-edged, Internal luftre dill ; externally 

 glimmering, femi-metallic. It is compofed of concentric, 

 lairellar, didintt concretions, inclofing a nodule, which is 

 often loofe. Surface rough ; external layers foft ; thofe of 

 the centre very foft ; brittle ; eafiiy frangible ; adheres to 

 the tongue ; is meagre to the touch, and moderately heavy. 

 Sp gr. 2.574. 



It does not melt before the blow-pipe, when heated alone ; 

 but enters into fufion with borax, and communicates to it a 

 dirty yellow colour. 



Occurs in the newefl fletz rock.-;, imbedded in the argil- 

 laceoiis ftrata that are incumbent on coal. 



It is found abundantly in Derbyfhire, and fome of the 

 neighbouring counties ; in Scotland, Norway, Denmark, 

 Bohemia, Silefia, Tranfylvania, France, and Siberia. 



The greateil proportion of the iron raanufafturcd in the 

 midland dillricls of England, as well as in many parts of 

 Scotland, is obtained from the two foregoing fubfpecies. 

 The metal v.-hich they afford, too, is, generally fpeaking, 

 of the belt quality. This is principally referable to the 

 liberal fupply of earthy matter in their compofition ; for, 

 without 3 fufficient production of fcoria, or cinder, in the 

 blall-furnace, the highly carbonized, and confequently 

 tnoft valuable, varieties of iron cannot be formed. Thefe 

 fubjefts will be more fully difcuffed in a fucceeding feftion 

 of the article. 



Subfp. 7. Pijifcrm iron-Jlone. — Colour yellowifh-brown, 

 of different fhades, pafTing fometimes to black;(h-browri. 

 This is its internal appearance. Externally, it varies ac- 

 cording to the nature of the ftratum in which it is im- 

 bedded, being reddidi, yellowifh, and liver-brown, and 

 even yellrnvifh-grey. Occurs in fmall fpherical grains. 

 Centre of the grain dull ; luftre incrcafing towards the fur- 

 face to gliftening. Internal frafture fine earthy ; exter- 

 nally, even. Fragments indeterminate, fomc«hat (liarp- 

 ; I 2 edged. 



