amphlet (554/2. "On the Origin of Coal," "Mem. Lit. Phil. Soc."
Manchester Volume VIII., page 148, 1848.), it will be worth your while
to array your facts and ideas against an aquatic origin of the coal,
though I do not know whether you object to freshwater. I am sure I have
read somewhere of the cones of Lepidodendron being found round the
stump of a tree, or am I confusing something else? How interesting all
rooted--better, it seems from what you say, than upright--specimens
become.

I wish Ehrenberg would undertake a microscopical hunt for infusoria in
the underclay and shales; it might reveal something. Would a comparison
of the ashes of terrestrial peat and coal give any clue? (554/3. In an
article by M. F. Rigaud on "La Formation de la Houille," published in
the "Revue Scientifique," Volume II., page 385, 1894, the author lays
stress on the absence of certain elements in the ash of coals, which
ought to be present, on the assumption that the carbon has been derived
from plant tissues. If coal consists of altered vegetable debris, we
ought to find a certain amount of alkalies and phosphoric acid in
its ash. Had such substances ever been present, it is difficult to
understand how they could all have been removed by the solvent action of
water. (Rigaud's views are given at greater length in an article on the
"Structure and Formation of Coal," "Science Progress," Volume II., pages
355 and 431, 1895.)) Peat ashes are good manure, and coal ashes, except
mechanically, I believe are of little use. Does this indicate that the
soluble salts have been washed out? i.e., if they are NOT present. I go
up to Geological Council to-day--so farewell.

(554/4. In a letter to Sir Joseph Hooker, October 6th, 1847, Mr. Darwin,
in referring to the origin of Coal, wrote: "...I sometimes think it
could not have been formed at all. Old Sir Anthony Carlisle once said to
me gravely that he supposed Megatherium and such cattle were just sent
down from heaven to see whether the earth would support them, and I
suppose the coal was rained down to puzzle mortals. You must work the
coal well in India.")

LETTER 555. TO J.D. HOOKER. Down, May 22nd, 1860.

Lyell tells me that Binney has published in Proceedings of Manchester
Society a paper trying to show that Coal plants must have grown in very
marine marshes. (555/1. "On the Origin of Coal," by E.W. Binney, "Mem.
Lit. Phil. Soc. Manchester," Volume VIII., 1848, page 148. Binney
examines the