1GU On Tribasie Phosphoric Acid. 



method with metallic tin (described by M. Aime Girard, 

 Bull. Soc. Cli. de Paris, I. p. 20) by which he found -±2.58 

 p. c. PO 6 . 



AL 0„ PO B +5 HO. 



1747-1831. Pyromorphite i Wallerius (Min. gron Blyspath). 



Kersten (Schw. J. LXI. 1) 

 may have been known before the edition of Wall. Mineralogy. 

 Klaproth discovered in the year 1784 that it contained phos- 

 phoric acid (Crell's Ann. I. 394), and Kersten, who analyzed 

 nine different kinds, found 16.52 p. c. PO 5 ; one sample gave 

 him 11.05 p. c. CaO 3, PO 5 . 



3 (PbO 3, P0 5 )+PbCl. 



1758-1821. Vwicmite, Cronstedt (Bloa Jarnjord, 182 Na- 

 tnrligit Berlinerblatt). 



Vogel, Laugier, Strohmeyer. 



Klaproth, in the year 1784, found this mineral to contain 

 phosphoric acid. 



Fe03, P0 5 + s 110. 



L770-1788. Apatite, Cronstedt (^Mineralogy). 



Prousl (J. d. Ph. p. XXXII. 241, phosphate calcaire). 



Tiic name Apatite, which Werner in the year 1786 gave to 

 this mineral, was subsequently to Vauquelin's analysis (Ann. 

 Chi. XXVI. 123). L798, applied to the whole class. 

 CaO 3, VO b +h Ca(Cl ; Fl). 



This is, by the way, the firel phosphatic mineral in which 

 phosphoric acid has been determined quantitatively ; and it 

 seeme significant thai the most important phosphate, in fad 

 the mosl important mineral to agriculture, a science that touches 

 so nearly the welfare of nations, should have been first selected 

 for analysis. In these facts is visible the hidden instinct of 

 mankind thai feels the important, the necessary, in nature. 



177- L823. Torbenrite, Born (Lytophycacium Born. 1.42). 



M. Richard Phillipe (Ann. Phil. II. 57). 



M. Gregor made, in 1819, the firsl analysis of this mineral, in 

 which he found 74.4 I', 0, (overlooking the PO*). Berzelius, 



