Vanadiferous Minerals in Western Colorado. 131 



Gooch crucible and washed with hot sodium carbonate solu- 

 tion, followed by very dilute nitric acid and finally by alcohol 

 to prevent turbid filtration. Drying of the sand was effected 

 by allowing the pump to draw air through the crucible until 

 no further loss in weight resulted. 



The water in the sand was then determined at 105°, at 300° 

 and above 300°. Similar water determinations having been 

 made on the unattacked substance, the differences gave the 

 water expelled at those temperatures from the soluble part. 



The sodium carbonate solution was acidified, evaporated, and 

 filtered, and the filtrate again evaporated, to recover the last 

 of the silica. To this was added a very small portion which 

 the nitric acid extract of the sandstone held in solution. The 

 sum represents the total silica of the decomposed portion of 

 the sandstone. 



The further analysis of the nitric solution presented diffi- 

 culty because of the vanadium it contained. It was carried 

 out in a variety of ways, of which the following seemed to be 

 most satisfactory. 



Barium was first precipitated by sulphuric acid and subse- 

 quently separated from traces of lead, calcium and vanadium. 

 Hydrogen sulphide then threw out further traces of lead and cop- 

 per with much sulphur from reduction of Y 2 5 to V„0 4 . After 

 evaporation of the filtrate to reoxidize vanadium and iron, the 

 alumina, iron and trace of uranium with much vanadium were 

 separated from calcium, magnesium and alkalies by three pre- 

 cipitations by ammonia solution. The combined filtrates were 

 evaporated, ignited, the residue transferred to a porcelain boat 

 with nitric acid, evaporated therein to complete dryness, and 

 exposed in a glass tube to a current of dry hydrochloric acid 

 gas, as recommended by Smith and Hibbs* for the expulsion 

 of vanadium from alkaline vanadates. The removal of vana- 

 dium being incomplete, the contents of the boat were again 

 evaporated with nitric acid and again distilled, and these opera- 

 tions were repeated till no further evidence of a brown distil- 

 late appeared. The boat now contained only magnesium and 

 alkalies with a little calcium. The distillates, containing all 

 the vanadium that was in the boat, had been collected in TJ- 

 tubes charged with water, and were eventually obtained in sul- 

 phuric solution for further treatment by evaporating with 

 sulphuric acid in porcelain. 



The precipitate of A1 2 3 , etc., was dissolved in nitric acid, 

 evaporated almost to dryness in platinum and boiled with 

 sodium hydroxide solution. These operations were repeated 

 on the precipitate after filtration. The iron and titanium thus 



*Jour. Am. Chem. Soc, xvi, 578, 1894. 



