20 Professor Apjohn on a Meteoric Stone 



cipitate ; and the sulphate barytes collected on a double filter, well washed, and 

 dried upon the edge of the sand bath, weighed 21.88 grains,* equivalent, as may 

 be easily calculated, to three grains of sulphur, or 8.25 sulphuret of iron, provided 

 the pyrites present be a binary compound. 



To the washings of the sulphate of barytes, sulphuric acid was added, so as to 

 throw down any excess of barytes used, and the whole having been passed through 

 a single filter, a mixture of muriate of ammonia and water of ammonia was poured 

 in until the latter became predominant in the fluid. The peroxide of iron thus 

 precipitated, being collected on a double filter, washed, and dried on the edge of 

 the sand bath, weighed 127.01 grains. Of this, 123.07 grains were solved in 

 muriatic acid, and then boiled with a considerable excess of potash, which again 

 threw down the iron ; and the alkaline solution, upon examination in the usual 

 manner, was found to contain a trace of alumen, which, however, was too insig- 

 nificant to be weighed. The peroxide of iron collected on a double filter, washed 

 and dried, was found to weigh 107.26 grains; and 106.16 of this, exposed to a 

 red heat, were reduced to 78.73. Hence, 



106.16 : 78.73 : : 107.26 : 79-54, and 

 123.07: 79.54:: 127.01: 82.08 = peroxide of iron, in the solution (A), 

 corresponding to 57-95 metallic iron- 

 To the solution deprived of the iron by ammonia, and which exhibited a 

 greenish blue colour, hydro-sulphuret of ammonia was added, and the black pre- 

 cipitate formed (sulphuret of nickel) was washed upon a single filter. It was 

 then transferred to a porcelain capsule, decomposed by nitro-muriatic acid, fil- 

 tered, to separate the sulphur, and then precipitated by caustic potash. When 

 washed upon a double filter and dried, the oxide of nickel weighed 4.39 grs. 

 Of this 4.05 grains were exposed to a red heat, and thus reduced to 2.67. 

 Hence, 



4.05 : 2.67 : : 4.39 : 2.89=the exact amount of the oxide of nickel, and which 

 is equivalent to 2.28 metallic nickel. 



The washings of the sulphuret of nickel were now treated with oxalate of 

 ammonia, which threw down oxalate of lime amounting after desiccation at 212° 



* The barytes was perfectly dry ; for by exposure to heat it suffered no further loss. 



