THE EARTH. 341 



Another is a martial pyrites, of a reddish-yellow 

 colour, black when powdered, not very firm in 

 its texture, and not attractible by the magnet. 

 A third consists of small particles of iron in a 

 perfectly metallic state, which give to the mass 

 the quality of being attracted by the magnet, 

 though in some specimens they do not exceed 

 two per cent of the whole weight, while in others 

 they extend to a fourth. These are connected 

 together by a fourth of an earthy consistence in 

 most, so that they may be broken to pieces by 

 the fingers with more or less difficulty. The 

 black crust is hard enough to emit sparks with 

 steel, but may be broken by a stroke with a 

 hammer, and appears to possess the properties of 

 the very attractible black oxide of iron. The 

 crust appears to contain nickel united with iron. 



" The solitary masses of native iron, that have 

 been found in Siberia, Bohemia, Senegal, and 

 South America, likewise agree in the circumstance 

 of being an alloy of iron and nickel ; and are 

 either of a cellular texture, or have earthy mat- 

 ter disseminated among the metal. Hence, a 

 similar origin has been ascribed to them. 



" In all the instances in which these bodies 

 have been supposed to fall from the clouds, and 

 of which any perfect account has been given, the 

 appearance of a luminous meteor, exploding with 

 loud noise, has immediately preceded, and hence 

 has been looked to as the cause. The stones 

 likewise have been more or less hot, when found 

 immediately after their supposed fall. Different 

 opinions however have been entertained on this 



