No. 31.— 1885.] 



PLUMBAGO. 



255 



" And talking of iron, look at that magnificent specimen of iron 

 pyrites (?), No. 3, so like a mass of polished silver, which was 

 found in Mr. Jacob De Mel's mine just as you see it. De Mel 

 tells me it has not been touched up in any way. In returning it 

 kindly say what you think of it — whether you think that by 

 any possibility the beautiful polish of its plates is due to the 

 contiguity of graphite ? I fancy you will say " no." Is the mass 

 a conglomeration of iron pyrites, or what ? De Mel said the 

 weight was 14 lb. 



" The amount of negative evidence I have obtained as to the 

 existence of anthracite in association with plumbago, or in any 

 form or place in Ceylon, seems to me overwhelming. But I should 

 like to have your opinion before closing up. Do you think it 

 possible that Gygax could have mistaken any black ore of 

 manganese or iron, or any other substance, for anthracite ? Cer- 

 tainly, no human being has seen any of the mineral since he 

 announced its existence." 



Mr. Murray's reply. 



"I have looked over the fine geological specimens you have 

 sent for inspection. 



" No 2 I should describe as semi-opaque quartz rock. 



" Quartz, properly speaking, is pure silica, of which rock 

 crystal is the purest and most transparent. 



" The specimens in No. 1 packet are very pretty samples of 

 iron pyrites. The green tints are due to the presence of sulphate 

 of copper, but in very small quantity. 



' 'I should much like to see a specimen of the compact heavy 

 ironstone (metamorphosed, I conclude) you refer to as being 

 associated with plumbago. Ceylon miners have probably the 

 same reason for objecting to its presence as colliers at home have 

 to the presence of trap rock in the coal measures, since in the 

 vicinity of such rock coal has lost its bright lustre and regular 

 face, as well as muchof its bituminous or inflammable character, 

 more nearly resembling anthracite than coal, and yet different 

 from both in that it has concretions of iron pyrites or other 

 minerals. 



"No. 3 specimen — iron pyrites — is simply splendid. 



" It is one solid crystal of that metal, and by no means a conglo- 

 meration of pyrites : the polished surface is quite natural, and not 

 due to the contiguity of plumbago. 



" Plumbago is held to be a metamorphosed form of anthracite, 

 and probably Gygax classed the impure forms of this mineral 



