142 MEMOIRS NATIONAL ACADEMY OF SCIENCES, VOL. XIII. 



He also says, page 634, that he has 



well-defined cases in his collection where the whitish-yellow (third class) compound is not combined with pyrrhotite 

 and does not envelope it, but is associated with another body graphite and surrounds large lumps of it as in other 

 cases it does the pyrrhotite. 



Of the graphite of Cosby Creek, Reichenbach says (Study XXI, p. 577) that he has two 

 specimens, one 



of which weighs not less than 34 and the other 44 grams. The two fit together on the rough edges exactly and were, 

 therefore, originally one piece, which weighed SO grams, and, judging from the other broken surfaces, must have 

 weighed 100 grams. 



On page 579, he gives the specific gravity of the Cosby specimen, about a cubic inch in 

 size, as 3.564 "which is considerably heavier than terrestrial graphite, apparently because of a 

 small content of iron. * * * This graphite occurs frequently in company with magnetic 

 pyrites." He gives a figure of the nodule, and on page 586 he states that he observed abun- 

 dant and fine examples of iron glass in his specimen of Cosby. 



In Study XXIa, pages 172 to 176, he says: 



If meteoric iron (as Cosby, Arva, etc.) be subjected for several weeks to the action of very dilute acid (cold), it 

 will gradually dissolve, and 



********* 

 there is obtained in this manner, with very dilute acid, a residue which makes up about 10 per cent of the meteorite 

 of Cosby. * * * The black fine-grained powdery residue, amounting to 2 per cent of the original mass, obtained 

 from the treatment of the above-mentioned 10 per cent residue with strong acid (applied with boiling heat for several 

 hours) yielded from 4 to 5 per cent of phosphorus, besides iron and nickel. Sulphur was lacking in it. 



********* 

 Three grams of the 2 per cent residue above. from the Cosby meteorite, immersed in concentrated cold hydrochloric- 

 acid, was dissolved in two years time almost completely down to an extremely small remainder containing almost 

 nothing but carbon. The same substance treated with the strongest acid, namely concentrated nitric acid or aqua 

 regia (heated) quickly dissolved entirely. 



******#* 

 In the toenite obtained from Cosby some sulphur was found, which is elsewhere lacking. 



Rammelsberg 8 received from G. Rose a specimen of iron sulphide from the Sevier iron 

 which contained particles of nickel-iron which "followed the magnet." He found by two 

 analyses 1 .5 and 1 .9 per cent of nickel and such proportions of iron and sulphur as, by reckoning 

 the nickel with the latter, gave iron sulphuret here also. The specific gravity of the iron sul- 

 phide in Sevier he determined to be 4.817. 



Rose * describes the Berlin specimen of Cosby Creek as follows: 



Many superficially oxidized octahedral fragments of this meteorite were received by gift from Professor Troost 

 together with small pieces of graphite and troilite from the same. The pieces extraordinarily resemble those of the 

 Arva iron; but the quantity of schreibersite is somewhat greater in one piece of Cosby Creek. On one piece graphite 

 is mixed with troilite. 



Rose also mentions a piece of Sevier County which he received from Reichenbach which 

 he does not find to differ from Cosby Creek. 



In 1864, Rammelsberg 10 analyzed the iron sulphide previously mentioned as obtained 

 from Rose, and obtained the following result: 



1 2 



Residue 0.74 0.60 



Iron ...'. 62.18 62.65 61.43 61.80 



Nickel (Co) 1.94 1.96 1.55 1.56 



Sulphur 35.14 35.39 36.42 36.64 



100 100 100 100 



Smith ll also gave an analysis of "troilite from Sevier," as follows: 



l 2 



Iron 63.80 63.48 



Sulphur 36. 28 36. 21 



No trace of other elements was found. 



