FORMATION OF COAL AND CARBONACEOUS MINERALS. 133 



entirely loose its origiiiJil outline hs in tlie case of No. 1, and it 

 was lustrous black, not silvery. The ash consisted chieUy ot" 

 alumina with a little oxide of iron and some traces of silica. 



In No. 5 the coke was shrunk, and of the same shape as the coal. 

 There were some bright black thread-like bands in No. 5 whicli 

 it was impossible to remove and these probably raised the per- 

 centage of volatile matter. I could not avoid this as I wished 

 to have the portions of coal immediately contiguous. 



Those I'esults seem to indicate that the bituminous part arises 

 from altei'ed resin, from the low ratio of fixed carbon and the 

 low percentage of ash — in the case of those from Newcastle, 

 oxide of iron, which could be introduced by infiltration, as could 

 also be the case with the alumina in the Lithgow Valley, as the 

 water of the overlying Hawkesbury Sandstone generally contains 

 sulphate of alumina in solution. 



In connection with a coal from Mittagong, the analysis of 

 which was published in the " Annual Report of the Department of 

 Mines" in 1878, I made the following remark, which has been 

 reproduced in Professor Liversidge's " Minerals of New South 

 Wales " :— 



" The bright lines of fracture were marked by numerous lense- 

 shaped cavities 00.5 to 0.10 inch in greater diameter, generally 

 tilled with a brownish pulverulent carbonaceous matter. These 

 were apparently the impressions and remains of seeds, and they 

 shewed traces of a dense cortical layer. The bituminous matter 

 on heating, glowed, emitted a smoky odour and burned away com- 

 pletely." These seeds were quite absent except in the bright 

 layers. Now if the seeds fell and were enclosed in resin, germi- 

 nation would be prevented and they would be preserved, whilst 

 if they fell in decaying vegetable matter all traces of them would 

 be lost. 



I conclude therefore that the bituminous coals yielding low and 

 valuable hydrocarbons on distillatiion are originally derived from 

 aromatic resin bearing plants, the resinous ligno-cellulose of 

 which contributed to the result, whilst the cambium or more 

 cellulosic portions were mostly lost by decay, a little being 

 converted into mineral charcoal. We can see the preservation 

 of resin in retinite and also in the more recent Kauri and grass 

 tree gums where the cellulose has often disappeared. 



Cannel. — I have no analysis of my own of this mineral but 

 give below the ratio of volatile matter and fixed carbons from 

 two analyses given in Percy's " Fuel " and one from " Watts 

 Dictionary." In nearly all books, analyses of true cannels are 

 mixed up with those of torbanite, or kerosene shale from Bath- 

 gate and elsewhere. The Lesmahago is a true typical cannel from 

 the middle ward of Lanarkshire and there called candle coal 

 (pi'onounced caun'l) where it was first used to give light in the 

 farmhouse kitchens, a lump being put on the red tire in the 

 evening. 



