of Australian Coal. 
191 
PORT STEPHEN. 
Slaty Coal. 
(Syn. — H ouille grasse, Brongniart.) 
External character .—Colour black, with a slight tinge 
of grey, structure foliated, fracture even, the fragments 
of indeterminate form; it soils the fingers, and is soft 
and brittle; specific gravity 1*31. 
Chemical character .—It burns easily, with a reddish 
flame ; it swells and agglutinates; its constituents are — 
Charcoal . 62*8 
Bitumen . 25*1 
Alumine ... 9 
Silica . . ... 2*7 
Deutoxide of manganese. P3 
Applied to the production of gas, one pound yields 
1 foot 806 cubic inches of illuminating, unpurified 
gas. The gaseous mixture, examined and treated by 
re-agents, contains in 100 volumes,— 
Sulphuretted hydrogen. 10 
Carbonic acid... 10 
Olefiant gas . 17 
Carburetted hydrogen. 1 ] 
Other inflammable gas. 52 
Every one hundred parts in weight yield— 
Coke . 7P2 
Coal tar and ammoniacal liquor 15*6 
Analysed with deutoxide of copper, the quantities of 
its ultimate elements, abstracted from the earthy matter, 
stand in the following proportion :— 
Carbon... 70*5 
Hydrogen. 20*4 
Oxygen ..00*0 
Nitrogen .. 9*1 
Geological situation .—It occurs in beds in the sand¬ 
stone of the carboniferous order (grts-bigarre). 
