1868.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 79 



Fe. I am greatly indebted to Dr. H. G. Torrey, assayer of the United 

 States Mint at New York, for making these fusions for me with sueb 

 great care that only small amounts of Fe could be found in the metal 

 after fusion. 



55.853 grams of the pure metal were melted in a scorifier and allowed 

 to absorb O until it had CDvered itself with the indeed oxide; the re- 

 sulting button, freed as much as possible from the melted oxide, weighed 

 45 grams. 



Drillings from this button were crushed to an approximately uniform 

 size, thoroughly mixed, marked off into squares, and samples for analy- 

 sis made up by taking some from each square. 



0.8318 gram were dissolved in HN0 3 , converted into sulphate, and 

 I the copper precipitated by two Bunsen cells, yielding 0.81G2 gram cop- 

 per or 98.12 per cent. 

 ! 2.0795 grams treated in this way yielded 2.0400 grains copper or 98.10 

 per cent. In the solution after the precipitation of the copper from the 

 latter were found 0.00028 Fe=0.013 per cent. 



2.7128 grams, determining the amount of copper going into solution, 

 as well as that made insoluble by treatment with AgN0 3 , yielded a total 

 of 2.G918 grams copper=98.14 per cent. 



Tie average of these three copper determinations is 98.12 per cent., 

 adding to this the Fe, we have 98 135 per cent. ; subtracting this from 

 100, we have 1.8G7 as the percentage of O present. 1.867 per cent. 

 0=16.67 per cent. Cu 2 0. We have therefore the composition of this 

 material : 



Per cent. 



Cu 83.317 



Cu a O 10.670 



Fe 0.013 



100. 000 



For the Cu 2 determination absolutely pure AgN0 3 was dissolved in 

 H 2 using 100 c. c. H 2 to 3 grains AgN0 3 . The Cu containing Cu 2 

 was weighed out, and the cold solution added, using 200 c. c. or 6 grams 

 AgN0 3 for each gram of the material. For the first few hours the 

 mixture was repeatedly stirred, after which it was allowed to stand, with 

 occasional stirring, for three to four days, being kept in a cool place all 

 the time. 



The residue, consisting of basic nitrate of copper and metallic silver, 

 was filtered and thoroughly washed. It was then treated with quite 

 dilute II 2 S0 4 , avoiding an excess. This dissolved the copper and, ow- 

 ing to its fine state cf subdivision, a small portion of the silver also. 

 The solution was filtered, evaporated, the silver precipitated by HC1, 

 filtered again, and evaporated till fumes of H 2 S0 4 were given off. The 

 residue was taken up by H 2 Q, the solution filtered, and the copper pre- 



