ion. He was an ardent opponent of slavery, and endeavoured also to
heal the breach between the Methodist and Anglican communions. He
published a _History of the West Indies_ (3 vols., 1808-1811), several
volumes of sermons, and, with Henry Moore, a _Life of Wesley_ (1792).

COKE (a northern English word, possibly connected with "colk," core),
the product obtained by strongly heating coal out of contact with the
air until the volatile constituents are driven off; it consists
essentially of carbon, the so-called "fixed carbon," together with the
incombustible matters or ash contained in the coal from which it is
derived. In addition to these it almost invariably contains small
quantities of hydrogen, oxygen and nitrogen, the whole, however, not
exceeding 2 or 3%. It also contains water, the amount of which may vary
considerably according to the method of manufacture. When produced
rapidly and at a low heat, as in gas-making, it is of a dull black
colour, and a loose spongy or pumice-like texture, and ignites with
comparative ease, though less readily than bituminous coal, so that it
may be burnt in open fire-places; but when a long-continued heat is
used, as in the preparation of coke for iron and steel melting, the
product is hard and dense, is often prismatic in structure, has a
brilliant semi-metallic lustre and silvery-grey colour, is a conductor
of heat and electricity, and can only be burnt in furnaces provided with
a strong chimney draught or an artificial blast. The strength and
cohesive properties are also intimately related to the nature and
composition of the coals employed, which are said to be caking or
non-caking according to the compact or fragmentary character of the coke
produced.

Formerly coke was made from large coal piled in heaps with central
chimneys like those of the charcoal burner, or in open rectangular
clamps or kilns with air flues in the enclosing walls; but these methods
are now practically obsolete, closed chambers or ovens being generally
used. These vary considerably in construction, but may be classified
into three principal types:--(1) direct heated ovens, (2) flue-heated
ovens, (3) condensing ovens. In the first class the heating is done by
direct contact or by burning the gases given off in coking within the
oven, while in the other two the heating is indirect, the gas being
burned in cellular passages or flues provided in the walls dividing the
coking chambers, and the heat tr