Re-examination of Microlite and Pyrochlore. 165 



polish on the glass. The solution was heated to 212° F., and the 

 excess of acid was allowed to escape. The fluid became turbid, 

 and when dry, a transparent coating lined the vessel. Warm 

 water dissolved the whole of the gum-like coating on the capsule, 

 forming a nearly colorless, transparent solution. Ammonia caused 

 a bulky white precipitate to form, and when separated by a filter, 

 it closely resembled the hydrate of alumina, mixed with magne- 

 sia. The entire mass was soluble in very dilute hydrochloric, 

 nitric, acetic, or tartaric acids. When its diluted solution in mu- 

 riatic acid was treated with a minute quantity of a solution of 

 sulphate of potash, columbic acid in its insoluble state was in- 

 stantly disengaged, and rapidly subsided. The precipitate, after 

 it had been washed and heated, weighed 1-770, corresponding to 

 59 per 100 of columbic acid. It was not pure, having carried 

 down titanic acid, lime, &c. The fluid containing an excess of 

 ammonia, from which the first precipitate had fallen, gave a pre- 

 cipitate with oxalate of ammonia. When calcined with sulphu- 

 ric acid, sulphate of lime, weighing -390, remained. By evapo- 

 rating the fluid to a dry mass, and heating the residue, -308 of 

 chloride of sodium were obtained. On adding an excess of am- 

 monia to the fluid, which had afforded the columbic acid by sul- 

 phate of potash, a precipitate was produced. The fluid and pre- 

 cipitate were saturated with hydrosulphuric acid gas. When the 

 precipitate had been separated, the ammoniacal fluid was mixed 

 with oxalic acid ; the precipitate calcined with sulphuric acid, 

 was sulphate of lime, weighing -820. A trace of tin oxide was 

 left, when this salt was dissolved in water. -820 -f- -390 = 1-2 10, 

 or '502 of lime. Oxalic acid dissolved the green precipitate con- 

 taining sulphur, leaving traces of sulphuret of lead. By tartaric 

 acid and ammonia, the titanic acid was retained, while sulphydrate 

 of ammonia precipitated sulphurets of iron, uranium, and manga- 

 nese. The titanic acid, left after burning off carbon, weighed 

 ■550, and the oxides from the sulphydrate of ammonia precipi- 

 tates -020. Three grains, thus treated, gave — 



or, per 100 parts, 5900 

 " 16-73 



" " 18-33 



" " 5-63 



" « 0-70 



" « 0-80 



3 013 10TI9 



