ACADEMY OF NATUKAL SCIENCES. 31 



The filtrate, or soluble part, was accurately measured and divided into four 

 portions for analysis — two portions were used for the determination of the iron, 

 nickel, cobalt, phosphorus, and alkaline earths ; a third portion was employed 

 to estimate the copper, and the fourth portion was reserved to answer in case 

 of accident. 



Two methods were used for the separation of the iron from the nickel and 

 cobalt — one by precipitation of the iron as basic acetate, and the other by pre- 

 cipitation with carbonate of baryta in the presence of an excess of chloride of 

 ammonium ; but in neither case was the separation perfected on the first pre- 

 cipitation, and traces of nickel remained with the iron even after the second 

 precipitation. The nickel and cobalt were separated by rnean^ of nitrite of pot- 

 ash, and the cobalt was subsequently converted into sulphate and as such 

 weighed. The lime and magnesia were separated by oxalate of ammonia, care 

 being taken to redissolve and reprecipitate the lime to insure its being free from 

 traces of magnesia. On spectroscopic examination of the precipitate, it proved 

 to be lime, free from other alkaline earths. 



The precipitate of iron, after being weighed, was fused with carbonate of 

 soda ; the product of the fusion was dissolved in chlorohydric acid, and the 

 phosphoric acid precipitated with molybdate of ammonia. This pkospho-molyb- 

 dic precipitate was dissolved in ammonia to free it from possible traces of silica 

 and other impurities, and the phosphoric acid precipitated from this solution by 

 an ammoniacal mixture of sulphate of magnesia and chloride of ammonium. 



The copper was precipitated as sulphide by sulphuretted hydrogen gas, redis- 

 solved in nitric acid, and determined as oxyd. 



The insoluble residue, containing free silica and undecomposed silicate, was 

 perfectly white, and free from all traces of Schreibersite. It weighed 0.1855 

 grm. equal to 4.24 per cent, of the specimen analyzed. It was fused with car- 

 bonate of soda, and the silica and bases determined in the usual manner. It 

 contained 0.159 grm. silica ; 0.0054 protoxyd of iron, with a minute trace of 

 alumina ; 0.0028 lime, and 0.0168 magnesia. 



The soluble and insoluble portions gave in the analysis the following per cent- 

 age composition : 



4 Considering the silica to exist as olivine. 



Iron 81.5G 79.44 



Nickel 9.17 9.17 



Cobalt 0.44 0.44 



Copper 0.08 0.08 



Phosphorus 0.49 0.49 



Silica 3.63 



Protoxyd of Iron ) 



with trace of t 0.12 



Alumina ) 



Lime 1.16 



Magnesia 2.43 



Chloriue, ) 



Sulphur, v . . . . minute traces traces. 



Chromium, ) 



99.08 99.69 



Combined with 2.73 ) 



Protoxyd of Iron, I 10.07 

 making Olivine . . ) 



