Re- examination of Microlite and Pyrochlore. 161 



C. To the transparent acid fluid, a few grains of chlorate of 

 potash were added, and the whole was heated. Chlorine gas 

 escaped, and after the liquor became cold, ammonia was added to 

 render it neutral. An excess of the same alkali was added, and 

 the vessel closed; a yellow hydrous precipitate subsided, becom- 

 ing flocculent. The clear fluid was passed through a filter, under 

 a bell blass, containing hydrate of lime, and the yellow precipi- 

 tate was collected on a filter, and carefully washed in water con- 

 taining muriate of ammonia. Diluted nitric acid redissolved the 

 yellowish brown precipitate, leaving on the filter a mere trace of 

 a white powder, which was added to that of B. The nitric so- 

 lution was rendered nearly neutral by carbonate of potash, and 

 clear crystals of pure sulphate of potash were dissolved in the 

 fluid while it was warm. When cold, the white heavy precipi- 

 tate which at first appeared, was mixed with a more crystalline 

 salt. Twelve hours after, no increase in the quantity of the lat- 

 ter salt was noticed. These precipitates were separated from the 

 fluid, and washed in proof spirit. Hot water dissolved one part, 

 leaving a heavy insoluble salt, which, after having been ignited, 

 weighed 0-150 grain, and had the characters of sulphate of lead.* 



D. The aqueous solution of the lighter salt, would afford no pre- 

 cipitate with ammonia. It was mixed with the proof spirit solu- 

 tion, and the whole boiled to disengage alcohol. Ammonia in 

 excess, gave a yellow brown precipitate, as before, and when sep- 

 arated by a filter, washed, dried, ignited, and cooled, 0320 gr. of 

 a nearly black matter remained. A few drops of nitric acid dis- 

 solved this matter ; crystals of carbonate of soda were added, and 

 the whole ignited. On dissolving the salts, which were green 

 colored, in water, a yellow solution resulted. The residue was 

 dissolved in nitric, with a little hydrochloric acid, and the solution 

 was decomposed by bicarbonate of ammonia in excess. After 

 the precipitate had been ignited, it weighed 0-099. The carbon- 

 ate of soda and ammoniacal solutions, contained oxides of uranium 

 and manganese. Neither phosphoric acid, earths, or other metal- 



* I here anticipate a doubt, which will arise in the mind of the reader, who has 

 seen it stated that the original solution was saturated with hydrosulphuric acid. 

 Contrary to the general belief, this acid does not decompose a solution of sulphate 

 of lead in hydrochloric acid. The fact is one of importance, as some well waters, 

 in contact with lead, cause this salt to form, and do not then give a precipitate with 

 hydrosulphuric acid. 



Vol. xlvi, No. 1.— Oct.-Dec. 1843. 21 



