■204: 



CHEMICAL MANUEES. 



He recognized their composition as that of a tetrabasic phosphate 

 of hnie Ca4P20y or P.^O^CaO. This analysis having given rise to 

 ■certain discussion, it was again taken up by Carnot on the one hand 

 ■iind on the other by Stead and Eidsdale. They found :- — 



TABLE LV.— ANALYSES OF CRYSTALS OF TETKABASIC PHOSPHATE 



OF LIME FOUND IN BASIC SLAG. 



99-7(5 



100 -OoO 



These results confirm the formula of tetrabasic phosphate of lime, 

 besides the two forms of crystals described. There were likewise 

 found brown or almost colourless needles of a hexagonal form. Their 

 iinalyses give the following figures : — 



TABLE LVI.— ANALYSES OF HEXAGONAL CRYSTALS FOUND IN 



BASIC SLAG. 



• Phosphoric acid . 

 Silica ^ • • . 

 Lime f ■•• . 

 Magnesia 1 . 

 Manganous oxide 

 Ferrous oxide 

 Ferric oxide 

 Alumina 

 Vanadium oxide 

 Sulphur 



Hilgenstock. 

 Per cent. 



34-94 



3-24 



57 -oo 



4-00 



99-73 



Bucking and Link. 

 Per cent. 



36-77 

 3-81 



53-51 

 0-40 



2-22 



1-78 

 1-09 



traces 



99-58 



Head. 

 Per cent. 



33-707 

 3-900 



53-536 

 0-486 

 0-790 

 1-286 

 4-857 



1-343 

 0-460 



100-365 



The differences which exist between these analyses are explained by 

 the difficulty which there is in isolating the crystals from the im- 

 purities which remain partially adherent thereto. Stead and Eidsdale 

 liave in fact distinguished two other varieties of crystals, black flat 

 needles, some of which are magnetic while the others are not so. 

 They have found the composition to be as follows : — 



