coal produced
by very different plants or parts thereof, in remarking that as the cells,
fibers, and vessels are formed of cellulose, and some of them isomeric,
the difference in composition is especially connected with the contents of
the cells, canals, etc., such as protoplasm, oils, resins, gums, sugars,
and various acids, various incrustations, etc. After the prolonged action
of water that was more or less mineralized and of multiple organisms,
matters that were soluble, or that were rendered so by maceration, were
removed, and the organic skeletons of the different plants were brought to
a nearly similar centesimal composition representing the carbonized
derivatives of the cellulose and its isomers. The vegetable debris thus
transformed, but still resistant and elastic, were the ones that were
petrified in the mineral waters or covered with sand and clay. Under the
influence of gradual pressure, and of a desiccation brought about by it,
and by a rising of the ground, the walls of the organic elements came into
contact, and the physical properties that we now see gradually made their
appearance.

The waters derived from a prolonged steeping of vegetables, and charged
with all the soluble principles extracted therefrom, have, after their
sojourn in a proper medium, deposited the carbonized residua that have
themselves become soluble, and have there formed masses of combustibles of
a different composition from that resulting from the skeletons of plants,
such as _cannel coal, pitch coal, boghead_, etc.

A thin section of a piece of Commentry cannel coal shows that this
substance consists of a yellowish-brown amorphous mass holding here and
there in suspension very different plant organs, such as fragments of
Cordaites, leaves, ferns, microspores, macrospores, pollen grains,
rootlets, etc., exactly as would have done a gelatinous mass that upon
coagulating in a liquid had carried along with it all the solid bodies
that had accidentally fallen into it and that were in suspension.

It is evident (as we have demonstrated) that other cannel coals may show
different plant organs, or even contain none at all, their presence
appearing to be accidental. The composition itself of cannel coal must be,
in our theory, connected with the chemical nature of the materials from
whence it is derived, and that were first dissolved and then became
insoluble through carbonization. Several preparations made from Australian
(New South Wa