FORMATION OP COAL AND CARBONACEOUS MINERALS. 137 



The objection to clei-ivntion from fats apply with even greater 

 force to tiie derivation from amber (succinite) and similar mineral 

 resins, probably little altered in constitution, a connection claimed 

 by Dana in Bath villite (" Mineralogy," p. 742), as amber contains 

 much less hydrogen than Bath villite or shale. 



The organic matter of the shale of this country is evidently a 

 very stable body. It is almost absolutely insoluble in naphtha, 

 carbon bisulphide and similar menstru;e. Tt is scarcely acted on 

 by exposure to the weather, as for years subjected to fierce sun 

 in summer, frost in winter, and rain at all times, it only becomes 

 slightly brown on the immediate surface. Long continued boiling 

 with caustic alkali dissolves from the powder, only a trace of 

 humus like matter, and fusion with caustic potash for two hours 

 gives a similar result, whilst amber is soluble in alkalis. The 

 bituminous matter of coal is insoluble in solution of caustic 

 potash, but fusion with potassium hydrate renders it largely 

 soluble in water. In this respect it is different from the "jet" 

 mentioned above which is insoluble in such menstruse as carbon 

 bisulphide, etc., in caustic potash solution, and long fusion with 

 caustic potash gives no more soluble matter than is obtained 

 from the shale itself. 



This "jet" subjected quickly to a cherry x-ed heat gives- 

 Volatile matter 41.12 



Carbon* 55.80 



Ash 3.08 



The ash was reddish coloured from the presence of oxide of iron. 

 Tiie immediately adjacent shale gave 9.16 per cent, of white ash, 

 whilst the volatile matter was 83.62 per cent., and the Hxexl 

 carbon 7.21, indicating a radically diflei'ent original constitution 

 from the jet, although in some respects that was different from 

 the bituminous matter of coal. 



5.— ON SOME MEANS OF POPULARISING THE STUDY 



OF CRYSTALLOGRAPHY. 



By F. Ratte, Mineralogist, Australian Museum, Sydney. 



*The carbon was left as a highly intumesced bright cokeLi,; I. ' ^ 



