[JOHNSTON-ELLSWORTH] ANNAHEIM METEORITE 77 



Analytical Methods 



Copper was separated by HoS in dilute sulphuric acid solution., 

 the sulphide ignited and weighed as oxide, and finally checked by 

 weighing after reduction in hydrogen. 



Iron was determined by titration with permanganate following 

 oxidation of organic matter and subsequent reduction. 



Nickel and cobalt were separated from iron by four basic acetate 

 precipitations, including an initial and a final precipitation of the 

 iron by ammonia. After evaporating the filtrates and filtering oft 

 the small amount of iron hydroxide thus recovered, the nickel and 

 cobalt were precipitated as sulphides, ignited to oxides in a silica 

 crucible, treated with a little HNO3, again ignited to oxides, and 

 finally weighed as metal after reduction in hydrogen. The nickel- 

 cobalt metal was then dissolved in HNO3 and treated with ammonia 

 to separate the minute amount of iron which is usually present. 

 Nickel was then separated from cobalt by the dimethylglyoxime 

 method. The filtrate containing the cobalt was evaporated to dryness 

 several times with strong nitric acid and finally ignited to destroy 

 the remaining organic matter. The cobalt oxide thus obtained was 

 dissolved in hydrochloric acid, precipitated by nitroso-beta-naphthol, 

 ignited and weighed as metal, after reduction in hydrogen. 



The nickel found was further checked by a direct precipitation 

 with dimethylglyoxime, the iron being held in ammoniacal citrate 

 solution. The nickel glyoxime thus obtained after solution in dilute 

 nitric acid along with a little citric acid, was reprecipitated by the 

 addition of ammonia and dimethylglyoxime solution. A considerable 

 amount of glyoxime solution is required to eft'ect complete repre- 

 cipitation of the nickel salt, so much, in fact, that it would appçar that 

 the glyoxime is partly decomposed by even dilute nitric acid. The 

 nickel glyoxime was evaporated to dryness several times with strong 

 nitric acid, ignited, reduced in hydrogen, and weighed. 



Direct weighing of nickel glyoxime, after drying at 120°, gives 

 slightly high results, in the writer's experience, probably owing to 

 occlusiW of the reagent. The determination as oxide is accurate 

 and in accord with the values obtained by reduction in hydrogen. 



Sulphur was determined by the Bamber method on an 8 gram 

 sample, carbon by combustion in oxygen and absorption in barium 

 hydroxide, phosphorus and silicon on a 7 gram sample. 



Chromium, vanadium, aluminium, titanium, and manganese were 

 sought and copper was determined in a 10 gram sample by the ether 

 separation method according to Blair and Ledebur. 



