t to the decomposition of sulphureted
hydrogen. Hoffman believes the sulphureted hydrogen must have passed
through the fissures of stratified rocks, but Bischoff is of opinion
that the sulphureted hydrogen must have been the result of the
decomposition of sulphate of lime in the presence of organic matter.
The theory of others is that sulphur owes its origin to the
combination of lacustrine deposits with vegetable matter, and others
again suppose that it is due to the action of the sea upon animal
remains. The huge banks of rock salt often met with in the vicinity of
sulphur mines, and which in some places stretch for a distance of
several miles, seem to indicate that the sea has worked its way into
the subsoil. Fish and insects, which are frequently found in strata of
tripoli, which lie under sulphur beds, induce the belief that lakes
formerly existed in Sicily.

The following is a list of the various strata which form part of the
crust of the earth in Sicily, according to Professor Mottura, an
Italian geologist:

_Pliocene._--Sandstone; coarse calcareous rock; marl.

_Upper Miocene._--Calcareous marl; gypsum, etc.; sulphur embedded in
calcareous limestone; silicious limestone; tripoli, containing fossils
of fish, insects' eggs, etc.

_Middle Miocene._--Sandstone containing quartz, intercalated with marl
of a saltish taste.

_Lower Miocene._--Rock salt; blue marl, containing petroleum and
bitumen; flintstone; ferruginous clay, mixed with aragonite and
bituminous schists; ferruginous and silicious sandstone.

_Eocene._--Limestone, containing diaspores and shells.

At times one or another of the strata disappears, while the order of
some is slightly reversed on account of the broken state of the crust.
Upon the whole, however, the above has been generally observed in the
various mines by the author referred to.

Sulphur mines have been operated in Sicily over three hundred years,
but until the year 1820 its exportation was confined to narrow limits.
At present the number of mines existing in Sicily is about three
hundred, nearly two hundred of which, being operated on credit, are,
it is understood, destined to an early demise. It is said that there
are about 30,000,000 tons of sulphur in Sicily at present, and that
the annual production amounts to about 400,000 tons. If this should be
true, taking the foregoing as a basis, the supply will become
exhausted in about seventy-five years.

In 1819 a law was passed