122 



The analysis with the norm calculated therefrom 



and iron. The ai 



lalysis 



is as under : — 





SiO, 



56-85 



AL 0,, 



14-76 



Fe., 0, 



4-48 



FeO 



1-21 



MgO 



3-84 



CaO 



7-91 



Na, 



5-34 



K,0 



1-91 



HoO + 



-12 



H..0 - 



•08 



C 0., 



Abs. 



TiO, 



3-11 



ZvO, 



Trace 



P.O, 



•51 



SO3 



Abs. 



CI, 



Trace 



F. 



-04 



Cr, O3 



Abs. 



MnO 



•12 



MCoO 



•05 



BaO 



Abs. 



SrO 



-01 



Li,0 



Abs. 



Orthoclase 



11-12 



Albite 



45-06 



Anorthite 



10-84 



Diopside 

 Hypersthene 

 Sphene 

 Ilmenite 



14-69 

 2-80 

 3-92 

 2-89) 



Hpematite 



4-48; 



Apatite 

 Quartz 



1-34 

 2-54 





99-68 



Classification — 

 II. 5. 3. 4. 



Magmatic Name — Tonalose. 



100-34 

 O for F -02 



100-32 



The unusual feature of this analysis lay in the highly 

 refractory nature of the ilmenite. Much of this mineral re- 

 mained still undecomposed after attack by sulphuric and 

 hydrofluoric acids in the manner described by Washington 

 and Hildebrandt, though repeated trials were made. Mit- 

 scherlich's method of treatment in closed glass tube with sul- 

 phuric acid was tried as a last resource, and gave figures of 

 1'23 per cent, and TSl per cent. Fe O. Professor Rennie, 

 however, kindly suggested the regrinding and retreatment of 

 the undecomposed residue, a method which afterwards ap- 

 peared in a paper by Hildebrandt. (i^) This gave on treatment 

 by Washington's rapid method, and after three regrindings, 

 only 100 per cent., considerable oxidation having occurred. 



(ifO Chemical News, October 23 and 30, 1908. 



