[johnston-connor] the BLITHFIELD METEORITE 191 



oxidation during the process. After several hours the liquid in the 

 flask was filtered. The filtrate besides containing iron due to the 

 decomposition of troilite was assumed to contain any SO3 existing 

 as such in the sample. 



The residue washed with alcohol was extracted with carbon- 

 tetrachloride to extract any separated sulphur and then treated 

 for recovery of any daubréelite according to J. L. Smith's directions 

 with nitric acid in which it is entirely soluble without separation of 

 sulphur, as also noted by that author. 



The residue remaining after the filtration of the nitric acid solu- 

 tion of the daubréelite was made up of undecomposed silicate and a 

 little graphite. 



The analysis of the nitric acid solution showed it to contain 

 chromium, iron, and sulphur only, and these in almost the exact 

 ratios required by the formula for daubréelite. — Fe S. Cr2 S3. 



Analysis of daubréelite 



Daubréelite of Meteorite Daubréelite (theoretical) 



Iron 18.1 xl9.1 



Chromium 37.6 x 36.1 



Sulphur 44.3 x 44.8 



100.00 100.00 



The above figures give respectively the following molecular 

 ratios : — 



Iron X 1.0 



Chromium x 2.0 

 Sulphur X 4.0 



In regard to the silicates it was found that this portion was almost 

 entirely insoluble in acids and had the composition of enstatite. The 

 treatments to determine soluble silicates were made with dilute and 

 concentrated acids with the following results: — Boiling dilute nitric 

 acid extracted 0.1 per cent CaO and 0.2 percent MgO, whereas strong 

 nitro-hydrochloric acid under like conditions of boiling but with 

 extended evaporation yielded the following as the result of disinteg- 

 ration : — 



Si02 1.6 per cent 



MgO 1.4 



CaO 0.33 



AI2O3 0.4 



Na20,K20 0.08 



