4 pinay 
COALS OF NEW SOUTH WALES. 179 
mineral in this ae and who informs me that as the “cover” 
increases the mineral becomes denser and passes into a slaty coal, 
which does not yield either the same quantity or quality of liquid 
hydrocarbons on distillation 
{t is curious to note wink a large percentage of ferric oxide is 
required to communicate a decided colour to the ashes, and it 
appears a: pe to judge by appearance of the ins — 
resent. Thus, some of the Newcastle coals with 9 per cent. or 
a little over are “decidedly red, whilst the sir J mea Creek 
coal containing 11 per cent. had only a faint pink colour. Dr. 
there may “ a large quantity of ferric oxide present without 
communi its colour, and ascribes this to its being in the form 
of calcium faerie silicate. In the ashes of our coals there is very 
little lime, and yet the iron does not communicate nearly the same 
colour that it does in other instances, as, for example, in —— 
—. is of a very decided red if it contains 10 per cent. of ferri 
0: 
* Determination of ash in coal, and incineration in general. Zeitschrift 
f. Anal. Chem, xix, p.131, Chem. News, xlii, p. 41. 
