26 ACCOUNT of a MINERAL 



with the fame advantage in the purification of nitric and mu- 

 riatic acids from the fulphuric. 



62. The acid of fugar, or oxalic acid, follows the fulphuric. 

 This acid takes the new earth from all the folutions above men- 

 tioned, and with it falls in a powdery form, excepting from the 

 fluate. It: is a curious facft, that the oxalate is foluble in mu- 

 riatic acid with partial decompofition. I obtained an oxalate 

 by dropping the acid of fugar into muriate of Strontites, which 

 I wadied well with cold water, and dried. I then introduced 

 it into muriatic acid, that did not difTolve it till a very little di- 

 ftilled water was added. The folution, in a few hours, had 

 depofited a fmall quantity of cryflals, which I dried on blotting 

 paper. They were perfiftent in the air, they diflblved in wa- 

 ter, and imparted to it the tafte of oxalic acid. This fluid was 

 not dillurbed in its tranfparency by fulphuric acid, and it oc- 

 cafioned in lime water a copious precipitate of very little fo- 

 lubility ; whence I inferred thefe cryflals were oxalic acid, and 

 their form did not contradidt the conclufion. On evaporating 

 the liquor from which they had been depofited, I procured a 

 powdery oxalate and cryflallized muriate. The reafon of this 

 partial decompofition I cannot at prefent afTign ; it cannot be 

 explained in the fame way that the partial decompofition of ful- 

 phate of poiafs or foda by nitric or muriatic acid is accounted 

 for. 



63. The third place belongs to the tartarous acid, which de- 

 compofes and caufes a milkinefs in the folutions of the earth 

 in nitric, muriatic, fuccinic, arfenic, boracic and acetous acids. 



64. Then comes the acid of fluor, which precipitates the 

 earth from its folution in all the acids I have tried, excepting 

 the three already mentioned as exceeding it in force. It is re- 

 markable, that a folution of fluate is not rendered turbid by 

 oxalic acid, though it be certain, that the oxalic has the flronger 

 attradtion ; perhaps a triple compound is formed. 



65. Nitric 



