Alumina and oxide of iron 10.56
Lime 61.48
Magnesia, water, and alkalies 2.02
------
100

Again, fineness of the particles results in their being speedily
heated to a uniform temperature, so that they do not serve as nuclei
for the condensation of the moisture existing in the furnace gas. The
calcined material, on reaching the lower end of the furnace, is
discharged on to the floor or on to a suitable "conveyer," and removed
to a convenient locality for cooling and subsequent grinding or
finishing. It, however, is not in the condition of hard, heavy
clinkers, such as are produced in the ordinary cement kiln, which
require special machinery for breaking up into smaller pieces before
being admitted between the millstones for the final process of
grinding; nor does it consist of an overburnt exterior and an
underburnt core or center portion; but it issues from the cylindrical
furnace in a condition resembling in appearance coarse gunpowder, with
occasional agglutinations of small friable particles readily reduced
to fine powder in an ordinary mill, requiring but small power to work,
and producing but little wear and tear upon the millstones. The
operation is continuous. The revolver or furnace, once started, works
on night and day, receiving the adjusted quantity of powdered material
at the upper or feed end, and delivering its equivalent in properly
burnt cement at the opposite end, thus effecting a great saving of
time, and preventing the enormous waste of heat and serious injury to
the brickwork, etc., incidental to the cooling down, withdrawing the
charge, and reloading the ordinary kiln.