134? ACCOUNT OP A MINERAL SUBSTANCE. 



Phofphate of 5. Phofphate of ammonia produces a very marked effect ; 



a"«° n bTue° r ™ S . for> iyhen meIted in a P Iatina r P oon > if> f ome of the white fub- 



bulc. fiance be added, a confiderable effervefcence takes place, and 



the two fubfiances rapidly unite. The globule, when cold, is 



deep blue, with a tinge of purple, but, when held between 



the eye and the light, it appears of a greenifh gray colour, 



C. 



It refifts nitric It is perfectly infoluble, and remains unchanged in colour, 

 and in every other refpect, when digefled in boiling concen- 

 trated nitric acid. 



D. 



is foluble in ful- It is dilfolved by boiling fulphuric acid, and forms a tranf- 



gjyy * C1 |!.I parent colourlefs folution, which is however only permanent 



tJon kts fall a while the acid remains in a concentrated flate ; for, if a large 



fulphate. quantity of water be added to the folution, or if the latter be 



poured into a veflel of diftilled water, the whole in a few 



minutes aflumes a milky appearance, and a white precipitate 



is gradually depofited, which cracks as it becomes dry upon 



the filter, and, from white, changes to a lavender blue colour, 



and again, when completely dry, to a brownifh gray. It is 



then infoluble in water, has not any flavour, is femi-tranfpa- 



rent, and breaks with a glofly vitreous fracture, 



This fubftance is much heavier than the original white pre- 

 cipitate ; and in a very flight degree may be dilTolved by boil- 

 ing muriatic acid, or by boiling lixivium of potafli. 



Upon examining thefe folutions, I found that both contained 

 the original white fubflance, together with fome fulphuric 

 acid j fo that the precipitate obtained from the fulphuric folu- 

 tion by the addition of water^ is a fulphate of the white 

 matter *. 



The whole is not however precipitated by water ; for a part 

 remains in folution, which may be feparated from the fulphuric 

 acid by either of the fixed alkalis, or by ammonia. 

 *thc fulphuric The fulphuric folution is not rendered turbid by the addition 



folution afforded f wa t er un til fome minutes at leaft have elapfed ; when, 

 an olive precipi- 

 tate by prufliate 



of potafh; # This fulphate is alfo precipitated when the fulphuric folution 



has been long expofed in an open veflfei to the air; and, according 

 as this may be moift or dry, the effeft is produced fooner or later. 



therefore, 



