which, being almost destitute of volatile matter, contains the greatest
quantity of carbon. In the higher beds are found, on the contrary,
lignite and fossil wood, substances in which the quantity of carbon
is infinitely less. Between these two beds, according to the degree
of pressure to which they have been subjected, are found veins
of graphite and rich or poor coal. It may be asserted that it is
for want of sufficient pressure that beds of peaty bog have not been
completely changed into coal. So then, the origin of coal mines,
in whatever part of the globe they have been discovered, is this:
the absorption through the terrestrial crust of the great forests
of the geological period; then, the mineralization of the vegetables
obtained in the course of time, under the influence of pressure and heat,
and under the action of carbonic acid.

Now, at the time when the events related in this story took place,
some of the most important mines of the Scottish coal beds had
been exhausted by too rapid working. In the region which extends
between Edinburgh and Glasgow, for a distance of ten or twelve miles,
lay the Aberfoyle colliery, of which the engineer, James Starr,
had so long

directed the works. For ten years these mines had been abandoned.
No new seams had been discovered, although the soundings had been
carried to a depth of fifteen hundred or even of two thousand feet,
and when James Starr had retired, it was with the full conviction
that even the smallest vein had been completely exhausted.

Under these circumstances, it was plain that the discovery
of a new seam of coal would be an important event.
Could Simon Ford's communication relate to a fact of this nature?