[DOWLING] THE FORMATION OF COAL 33 
Compare with this the analysis of the Swansea four foot seam near 
Swansea and a similarity will be apparent. 
Swansea four foot seam. 
(Analysis from Bull. Geol. Surv. Eng. and Wales). 
Carbone ae ee 91.54 
Éivdrogen rer 4.62 Ash 2.2 per cent. 
Oxygen and Nitrogen... 3.84 
100.00 
In this we suggest a theoretical method by which could be produced 
a coal similar to the Welsh anthracite with very low ash. 
For beds not deeply buried. 
For beds in the same field which show high ash and lower carbon 
percentage, it might be suggested that less pressure resulted from their 
position and that greater opportunity was given for the accumulation 
of earthy material in the beds, raising their ash correspondingly. These 
suggestions have weight and cannot be disregarded. If however the 
high ash is not to be thus accounted for we still have an argument in 
that waste of material will raise the ash. For the marginal portions, 
then, we will assume an escape of gas containing hydrocarbons. These 
we will call mixtures of carbon dioxide and marsh gas in various pro- 
portions by weight. As the combinations are supposed to be formed 
readily and their escape not greatly retarded the loss for the time interval 
allowed in the previous example will possibly be much greater. 
Allowing for losses of 75 per cent and over the results will be found 
in the following table :— 

Ratio Loss 75% Loss 77% Loss 78% 
C 78.28 C Sede C 83.41 
CQ? 44 H 7.08 H 7.09 H Pale 
= ir O 10.64 O 7.00 O 4.91 
CH“ N 4.00 N 4.34 N 4.55 
100.00 100.00 100.00 
CO? 44 C 80.00 C 83 .47 C 85.45 
—— = — H 8.00 H 8.13 H 8.20 
O 8.00 O 4.06 O 1:81 
OHS 116 N 4.00 N 4.34 N 4.54 
100.00 100.00 100.00 
