IRON. 



Oxyd of iron 

 Oxyd of manganefe 



Carbonic acid 

 Water 



but it is liable to great variation in t!ic proportion of its 

 ingredients. In a recent examination by Collet-Dcfcotils, 

 the following refult was afforded : 



Fragments of quartz - 2o^ 



Red oxyd of iron - 4^-45 



Brown oxyd of manganefe i.So 



Lime - - .J 2 



Magnefia - - i.t.S 



Carbonic acid, water, and lofs 44.67 



a compaft fraftare, was femi-hard, approaching to hard, anA 

 of the fpccitic gra\'ity of 3 .6. It confiUcd of 



Peroxyd of manganefe - - 64 



Silex - - - - 13 



Volatile matter - - 14 



Lofs (occafioned by an accident ' 

 dryii.g fome carbonat of mano 

 Bcfe on the filler) 



!t inT 

 ^gu- ^ 



Annales de Chimie, t. 75. 



Confiderable difference is very likely to exift in the chff- 

 rv.icA contlitution of this mineral, and the total abfence of 

 iron, in tlie prefent cafe, may certainly be regarded as rather 

 an extraordinary circumftance. Indeed, Werner's judgment 

 is much too accurate to admit the fuppoiition, tliat the varie- 



■ ties which have come under his infpcftion were dcftitute of 



100. it; but from the very preat produce of manganefe in tlie- 



above analyfis, and the general cliErufter of tlie fpecies, in 



Annales de Chimie, t. jS. imparting a violetrblue colour to borax, there can be little 



The fpecific gravity of the fpecinien analyfed in this cafe doubt that this, if not both fub-fpecies of black iron-ltone. 



properly, ores of the former metal. 

 Subfp. 2. BL-ici Hematite. — Colour inclining more to fteel- 

 grcy than the preceding fub-fpecies. Occurs mafTive and 

 reniform. Internally it is glimmering ; luilre femi-metaUic. 

 Frafture delicately fibrous, paffmg into even. Fragments 

 wedgc-lliaped. Occurs in granular diilincl: concretions. In 

 other refpefts agrees with the preceding. 



Before the blow-pipe, both the members of this fpecies 

 melt with borax into a violet-blue coloured glafs. No exaft 

 analyfis has yet been made of the black hematite ; but its 

 chemical conilitution is in all probability very much fimilar 

 to that of the former fub-fpecies. 



Black iron-itone is found in primitive and fletz mountains, 

 accompanied with brown and fparry iron-!lone and quartz. 



It occurs at Naila, in Bareuth ; Rafchau, in Saxony ; 

 HclTia, the Upper Palatinate, and the Hartz. 



Sp. 10. Clay iron-Jlons. Thoneifeiifte'in. Le fer argileux. 

 Ferrum ochraceum argillaceum. 



Tliis widely diilributed, and highly valuable mineral, is 

 divided into feven fub-fpecies ; reddle, columnar clay iron- 

 ftone, lenticular clay iron-ftone, jafpery clay iron-ftcne, com- 

 mon clay iron-i\oue, iron kidney, or kidney-fhaped iron-ore, 

 and pea ore, or pea-fhaped iron-ore. 



Subfp. I. RediiU.—to\om light brov.r.ifh-rcd. Occurs 

 only maffive. Principal frafture flaty, glimmering. Crofs 

 fracture earthy, dull. Fragments tabular, fplintery or in- 

 determinate. Streak lighter than tlie fraflure furface, and 



3.693 ; and its colour was brownifh-yellow 



It occurs in primitive and fjcondary mountains ; in the 

 former, in veins; in the latter, in beds. 



It is found fparingly in Britain ; and not very abundantly 

 in Sweden, Norway, Switzerland, Siberia, Bohemia, and 

 Saxony. At Schmalkalden, in HefTia, however, there is a 

 ^ed from aj to 30 fathoms thick ; and in different parts of 

 Wedphalia, Siiria, Carinthia, &c. it is very plentiful. A 

 whole hill, in the province of Bifcay, is compofed of it, 

 which is faid to have been worked for feveral thoufand 



an ore of iron, and the metal produced 

 from it is confidered to be peculiarly favourable for ftecl- 

 making ; but whether this is any thing more than a mere 

 prejudice, feems greatly to be queftioned. 



Sp. 9. Black Iron-June. Schwann eijhijlem. La mine lie 

 ftr noire. Ferrum ochraceum nigrum. 



This is divided into two fub-fpecies ; compaft black iron- 

 ftone, and black hematite. 



Subfp. I. Compaa Blach Iron-Jlone — Colour between 

 blueifh-black, and dark fteelgrey. Occurs maffive, and in 

 various imitative forms. Surface dull, or faintly glimmering. 

 Internally it is bordering on gUflening, and its luilre femi- 

 meta lie. Frafture commonly conchoidal, fometimcs un- 

 even. Fragments indeterminate, fharp-edged. Streak fhin- 

 ing, but unchanged. It is femi-hard, brittle, eafily frangi- 

 ble, and heavy. Sp. gr. 4 076, according to Wiedemann. 



This mineral had for a long time been clafTed as an ore of more fhining. Soils ftror.gly, and may be written with. It 

 manganefe, and was removed to the prefent genus from is foft, and very fcft, fcclile, eafily frangible ; ftrongly ad- 

 fome particular diftinftions that were pointed out by Werner, herent to the tongue, meagre to the touch, and moderately 

 between the compaiS grey manganefe ore, of which it had heavy. Sp. gr. 3. 1 391 to 3 931. 



ufually been confidered a variety, and the fub-fpecies now It decrepitates and blackens at a red heat, and, in a more 

 under examination. M. D' Aubniffon, however, in the elevated temperature, melts into a kind of pumice of a grecn- 

 eourfe of his late rcfearchcs, has fubjefted a fpecimen of it ifli-grev colour. 



to chemical analyfis ; and inllead of finding, iron to be its It moll generally occurs in the newer clay flate ; and Is 

 principal ingredient, has afcertained it to be almofl wholly found in Thuringia, Saxony, Silefia, Salzburg, HeiTia, and 

 compofed of manganefe and filex. This would, perhaps, be Siberia. 



a fufEcicnt authority for transferring it to the latter genus It is fcarcely ufed for any other purpofe than drawing. 

 ?.gain ; but as the Wcrnerian claflification has been uni- Subfp. 2. Columnar Clay Iron-Jlonc. — Colour brownidi-red, 



■ " red. Oc 



5 angular. 



formly adhered to in the prefent article, it has been deemed 

 bell to continue its enumeration here, and accompany the 

 account of it with the particulars of M. D'Aubuiii'on's 

 inq'^iry. 



The fpecimen he examined came from Rafchau, in Saxony, 

 and V7as of a blueifh-black colour mixed with grey, 



pafling fometinies to cherry red. Occurs mailive, and m 

 pieces which are more or iefs angular. Surface rough and 

 dull. Internaliy dull, and frafture earthy. It mofl ufually 

 occurs in columnar diilinft concretions. Streak blood-red. 

 It is foft, very eafily frangible, brittle, meagre to the touch. 



It 



It had. adheres flightljj to the tongue, and is moderately heavy 



