146 
vation of the Pennine Eange. The cleavage is often locally 
changed in the neighbourhood of faults, and occasionally it is 
without any definite direction. 'Now, if a piece of coal of this 
district, with clear, bedded planes be put on a fire, it will be 
found that the gas is emitted more rapidly, from the side or 
end in the direction of the bedding plane, than from the other, 
and, I believe, that the coking coals are tbose in which the 
jras has not free access to the exterior, but has to work its 
way through broken cleavage planes, or through long bedded 
planes, thus becoming condensed. It may be mentioned, in 
support of this, that small coals coke better than larger ones. 
The operation of coking is a simple one. The coals are 
thrown into a fire-brick oven of considerable thickness, pre- 
viously heated to redness ; the heat from the oven gradually 
communicates itself to the coal, roasting it, so to speak, 
without the admixture of atmospheric air, and slowly driving 
off the hydrogen and volatile parts of the coal, and leaving 
the carbon or coke in a solid and often hard condition. 
When used in this condition it makes no smoke, and the 
introduction of a blast or strong current of air, makes it 
burn with a very intense heat. In this form it is used for 
melting iron, steel, brass, etc., and, indeed, any purpose where 
intense heat is required in the body of fi.rc. Coals that will 
not coke by this process, are called non-coking, yet by reduc- 
ing a coal that is considered a non-coking one to a fine 
powder and heating it slowly, I have obtained a fair coke. 
IN'early the whole of the coals of the West Riding will 
make coke of some kind. That made from the Better-bed 
and the Churwell Thin coals is very hard and good, and 
contains such a small quantity of sulphur, that it is exclusively 
used for the manufacture of the best Yorkshire iron. Indeed, 
the demand for this coke is greater than the supply, and the 
Better-bed coal cannot be bought, being all consumed by the 
proprietors of the collieries and ironworks. I am informed 
