On Tribasia Phosphoric Acid. L61 



in 1819, (Systeme mineralogique) found 72.15 l\ < > . Phillips 

 obtained P0 5 =16, U a O a =60, CaO=9, by boiling the nitric 

 acid solution with excess of Potassa, neutralizing with Ac and 

 precipitating with PbO Ac. The two oxydes were Beparated 

 by NH 3 . 



IT 2 3 2, P0 5 + CnO,II<) + 7 HO. 



1779-1840. Plwmbogummite, De Lisle (Demeste Lettres snr 

 la mineralogie). 



Damour (Ann. d. M. III. xvii. 191). 



Phosphate of lead was known long ago. But Berzelins, 

 who made the tirst analysis of this mineral in the year 1820, 

 did not find phosphoric acid (Schw. J. XXVII. 65). Du- 

 frenoy noticed a little in 1835 (An. Ch. Phys. I. IX. II". 

 Damour fuses with KO, CO 2 , and boils the filtrate with pure 

 SiO 2 . The filtrate from the residue is evaporated with hydro- 

 chloric acid (to separate SiO 2 ) and ignited with a known 

 weight of sesquioxyd of iron. 



3 (Pb03, P0 5 ) + « (Al, 3 3 HO.) 



1791-1818. Lazulitr. Widenmann (Bergm. J. 346, April). 



Fuchs (Schw. J. XXIV. 373). 



Minerals of this character were known before, but ;i> their 

 composition had not been previously investigated, a greal dif- 

 ference of opinion prevailed among mineralogists as to placing 

 them. Trommsdorff made the first analysis, in which lie found 

 66 p. c. Al s 3 , Klaproth soon afterwards 71 p. c. A!.. ' » , both 

 overlooking the phosphoric acid. Fuchs boils the pnl 

 mineral with caustic potassa, evaporate- and fuses it. Ele pro- 

 ceeds then as described under Plumbogummite,but w PO 

 as Ca03, PO s . 



Al, 0„P0 6 (MgO, FeO) HO. 



Up to the end of the eighteenth century eight phospha 

 minerals only were known, and the composition of but on< 

 them had been ascertained, that of Apatite. From thai time, 

 1788, the analysis of phosphates rested for Bixty years, until a 

 Berzelius' investigations; we meet the next analysis of ap 



