251 



the marks of Mr. Davis's chisel, was placed in my hands by Rev. 

 Joseph Tracy, of Boston, it having been forwarded to him by 

 Rev. H. M. Blodgett, to whom it was given by William Coppin- 

 ger, Esq., of Philadelphia, who was the recipient of it from 

 Mr. Davis. 



The larger mass, which I have the pleasure of exhibiting to 

 the Society, presents a part of the specimen cleaned from oxide, 

 while the small slabs show the texture of the iron in the central 

 parts of the mass. 



The specimen had been drilled and filed when I first saw it, 

 and my attention was particularly arrested by the filed surface, 

 as the arrangement of the particles, viewed under a lens, was 

 not only unusual, but closely resembled that of the unalloyed 

 part of meteoric iron. In all artificial irons, we find the parti- 

 cles disposed in such a way, that we may arrange the kinds 

 under two heads. 1st, crude, or cast iron. In this the particles 

 crystalline, and often distinctly crystallized^ are separated, by 

 the occurrence of two forms of carbon intermixed with them, as 

 graphitic carbon and pure graphite. These foreign bodies pre- 

 vent the cohesion of the particles, and rarely permit them to 

 come in contact ; hence this variety of iron is brittle ; rarely 

 bending or bearing the hammer without fracture. In that variety 

 of wliite iron, containing the smallest proportion of graphitic 

 carbon and no graphite, the size of the crystals is large, but they 

 are not solid, as their internal structure is impaired by the pres- 

 ence of three or four per cent, of graphitic carbon. As a whole, 

 this white iron often contains more pure iron than is found in 

 some kinds of marketable malleable iron. The variety known 

 as " Kishy " iron, is the exact representative of Meteoric iron; 

 which consists of pure, unalloyed iron, in which alloys of iron 

 and nickel, and nickel and iron are so distributed, as to prevent 

 a regular crystallization. 



2d. Malleable, or ductile iron. The removal of the two forms 

 of carbon, by the process of refining crude iron, as usually 

 practised, allows the crystalline particles to unite, so that a 

 degree of perfect malleability is attained. In the iron reduced 

 from the ore directly, by alternate exposure to contact with 

 highly heated carbon and hammering, the oxide partly reduced, 



