68 



JOURNAL, R.A.S. (CEYLON). [VOL. XV. 



in his monograph on "Plumbago," do full justice to 

 the Ceylon mineral, and the analyses may be regarded as 

 representative of the best qualities of lump plumbago in 

 both cases :— 



Canada, Buckingham : vein gra 



phite ; variety foliated 

 Canada, Buckingham : vein gra 



phite ; variety columnar 

 Canada, Grenville : vein gra 



phite ; variety foliated 

 Canada, G-renville : vein gra 



phite ; variety columnar 

 Ceylon : vein graphite ; variety 



columnar 

 Ceylon : vein graphite ; variety 



foliated 



Ceylon : vein graphite ; variety 



columnar 

 Ceylon : vein graphite ; va 



foliated 



Specific 

 Gravity. 



Volatile 

 Matter. 



Carbon. 



Ash. 





Per cent. 



Per cent. 



Per cent. 



2-2689 



0-178 



99-675 



0-147 



2-2679 



0-594 



97-626 



1-780 



2-2714 



0-109 



99-815 



0-070 



2-2659 



0-108 



99-757 



0-135 



2-2671 



0-158 



99-792 



0-050 



2-2664 



0-108 



99-679 



0-213 



2-2546 



0-900 



98-817 



0-283 



2-2484 



0-301 



99-284 



0-415 



The following analyses* by Cochran of Ceylon plumbago 

 dust show the total percentage of graphite and of sulphur, 

 the latter being regarded as an objectionable impurity : — 





1 



2 



3 



4 



5 



6 



7 



Carbon, percent. ... 

 Sulphur, per cent. 



99-3 

 trace 



99-00 

 trace 



98-05 

 0-02 



98-00 

 0-06 



97-08 

 0-09 



95-03 

 0-59 



95-09 

 0-83 







8 



9 



10 



11 



12 



13 



Carbon, per cent. 

 Sulphur, per cent. 





91-35 

 0-75 



90-05 

 0-02 



88-06 

 0-19 



88-06 

 0-38 



88-75 

 0-72 



87-04 

 0-75 



* " Manual of Chemical Analysis," p. 262. Mr. Ph. Freudenberg 

 writes : "Cochran's analyses were made of plumbago dust, as he calls 

 it, inasmuch as we, for instance, grind the lumps to powder before 

 sending them to Mr. Cochran to ensure evenness of sample ; but no ' dust ' 

 in the commercial sense contains carbon up to 90 per cent." 



