412 PHYSIOGRAPHY. CLASS II. 



4. The refractory property of this metal, and the cir- 

 cumstance that it is not acted upon by the greater part of 

 the chemical reagents, render it extremely valuable in the 

 construction of philosophical and chemical apparatus. It 

 is used also for covering other metals, for painting on por- 

 celain, and, like gold or silver, for various other purposes. 



GENUS IX. IRON. 

 1. OCTAHEDRAL IRON. 



Octahedral Iron (excepting the first subsp.). JAM. Syst. 

 Vol. III. p. 97. Man. p. 264. Native Iron. PHILL. 

 p. 213. Gediegen Eisen. WEIIN. Hoffm. H. B. III. 2. 

 S. 187. Meteoreisen. HAUSM. I. S. 114. Gediegen- 

 Eisen. LEONH. S. 319. Fer natif. HAUY. Tabl. comp. 

 p. 93. Traite, 2de Ed. T. III. p. 531. 



Fundamental form. Hexahedron. Vol. I. Fig. 1. 

 Simple form. O, Vol. I. Fig. 2. Irregular forms, 



grains. 

 Cleavage none. Fracture hackly. Surface rough, 



the grains rough and uneven. 

 Lustre metallic. Colour pale steel-grey. Streak 



unchanged, shining. Strong action upon the 



magnet. 

 Ductile. Hardness = 4-5. Sp. Gr. = 7-768, the 



meteoric variety from Elbogen. 



Compound Varieties. Small crystals arranged in 

 rows. The composition in large masses becomes 

 visible, if an artificial surface is produced by cut- 

 ting and polishing, and this surface exposed either 

 to the action of nitric acid, or allowed to tarnish by 

 heat. The surface of the masses is commonly oxid- 

 ised, and sometimes marked with impressions of 

 prismatic Chrysolite. 



