9 



aromatic body was obtained. This substance was very 

 volatile, burned easily with a smoky flame and melted at 

 about 50° C. 



The presence of this carbonaceous substance in the dia- 

 mond matrix is most interesting and tends to confirm 

 Professor Cohen and Mr. Dunn's hypothesis that the car- 

 boniferous shales that are penetrated by the diamond bearing 

 "pipes" have been the source of the carbon which is now 

 found in the crystalline form as diamond. It is unfortunate 

 that the quantity of the substance obtained was too small 

 to admit of a full investigation of its composition and 

 properties. 



The results of the examination of the remaining speci- 

 mens, which are samples of the deposit obtained by washing 

 the "stuff" at Kimberley, are interesting, as showing the 

 minerals which accompany the diamond in the matrix : — 

 100 grams, of the "Fine heavy Deposit" contained — 



Garnet 10-76 grams. 



Bronzite 3'64 



Ilmenite 54-80 



Pyrites 0-14 



Mica 0-20 



Limonite 16-12 



Pieces of the rock which have \ 



escaped disintegration with >-10'84 

 some Limonite j 



Coarse sand — a mixture of all" 



3arse sand — a mixture of all 1 „ , „ 

 the above / ^'^^ 



99-96 



The composition of the limonite and bronzite are o-iven 

 below : — 



Limonite. Bronzite. 



Si O2 per cent 6-93 55-17 



AlA „ 6.85 2-95 



FeaOa „ 71-40 



