ACCOUNT OF A MINERAL SUBSTANCE. 135 



therefore, fome pruffiate of potafh was added immediately 

 after the water, the colour of the liquor became olive green, 

 and a copious precipitate, of a beautiful olive colour, was 

 gradually depofited. 



Tinaure of galls, after a few minutes, caufed the liquor to orange by tinft. 

 become turbid, and a very high orange-coloured precipitate ga ls> 

 was obtained. 



A few drops of phofphoric acid were added to a part of the jelly by phof- 

 concentrated fulphuric folution ; and, after about 12 hours, P bonc acid » 

 the whole became a white opaque fiiff jelly, which was info- 

 luble in water. 



Potafh, foda, and ammonia, whether pure or in the ftate of ^te flakes by 



carbonates, feparate the fubftance in queftion from the ful- 

 phuric folution, in the form of a white flocculent precipitate ; 

 and, when thefe alkalis are added to a confiderable excefs, 

 they do not rediffolve the precipitate, unlefs they are heated ; 

 then, indeed, the fixed alkalis act upon it, and form combi- alkaline combi- 

 nations which have already been mentioned, but which we nations, 

 fhall foon have occafion more particularly to notice. 



E. 



1. The white precipitate, when recently feparated from Muriatic folu- 



potafh, is foluble in boiling muriatic acid: and this folution tM ?" of the . 

 r .••■'. . white precip. 



may be considerably diluted with water, without any change 



being produced. 



2. A part was evaporated to drynefs, and left a pale yellow Evap. left a yel- 

 fubftance, which was not foluble in water, and was diffolved lowrefidue. 

 with great difficulty, when it was again digefted with muriatic 



acid. 



3. Pruffiate of potafh changed the colour of the muriatic olive precip. by 

 folution to an olive-green ; the liquor then gradually became P rufflate » 

 turbid, and an olive-coloured precipitate was obtained, fimilar 



to that which has been lately mentioned. But, 



4. If fome nitric acid was previoufly added to the muriatic but none if ni- 

 folution, then the pruffiate changed the liquor to a grafs-green, ]5JL? ld firft 

 but did not produce any precipitate. 



5. Tindure of galls, in a few minutes, formed an orange- Orange pr. by 

 coloured precipitate, like that which has been mentioned j £ 



but, if the acid was in too great an excefs, it was neceffary to 

 add a fmall quantity of lixivium of potafh or foda, before the 

 precipitate could be obtained. 



-6. A 



