58 BULLETIN 149, UNITED STATES NATIONAL MUSEUM 



oughly with a hand magnet and all attracted material was removed 

 and added to the metal. This separation gave: 



Grams 



Attracted portion 3. 8425 



Unattracted portion 15. 2362 



19. 0787 



The attracted portion was all digested in aqua regia, evaporated 

 to dryness, taken up in hydrochloric acid and filtered. The undis- 

 solved portion was washed thoroughly in hot water, then digested 

 for one hour in hot 10 per cent sodium carbonate solution, filtered, 

 and the then insoluble residue washed thoroughly w4th hot water, 

 then with dilute hydrochloric acid and again with hot water. The 

 residue was weighed as insoluble siUcate. This gave: 



Grams 



Dissolved 3. 5501 



Insoluble .2924 



3. 8425 



The alkaline and acid filtrates were combined, evaporated to dry- 

 ness, taken up in hydrochloric acid, and the silica separated and 

 determined in the usual manner. The solution was then made up 

 to 500 cc. in a calibrated flask at 38° C. and divided into aliquot 

 portions. Portions of 50 cc. (equivalent to 0.35512 gm.) were used 

 for determination of MnO, P, and S; 100 cc. (0.71024 gm.) for the 

 portion used for Fe, FeO, Ni, CO, CaO, AI2O3, and MgO, and the 

 remaining 250 cc. (1 .7756 gm.) was used for determination of Cu. 



The portion for sulphur was evaporated to approximate dryness 

 on the steam bath, an excess of hydrochloric acid and of potassium 

 chloride added and twice again evaporated to approximate dryness 

 with concentrated hydrochloric acid to expel nitrates. The potas- 

 sium chloride unites with the ferric chloride to form a crystalline 

 double salt, thus facilitating evaporation. The material was then 

 taken up in hydrochloric acid, precipitated with barium chloride and 

 weighed as barium sulphate on a small Gooch crucible. 



The portion for manganese was evaporated to dryness several 

 times with strong nitric acid, taken up in nitric acid, diluted and 

 boiled with bromine, precipitate wdth ammonia. The precipitate 

 was dissolved in nitric acid, thus freeing from chlorides, oxidized with 

 silver nitrate solution and ammonium persulphate, and determined 

 colorimetrically. 



The portion for phosphorous was likewise evaporated with nitric 

 acid several times to free from chlorides, precipitated with ammonia, 

 dissolved in nitric acid and precipitated with ammonium molybdate 

 reagent. It was filtered on a small Gooch crucible and w^eighed 

 as phosphomolybdic anhydride, 24M0O3.P2O5. 



