age thereto, and other
misfortunes not within control, and consequent upon the use of the
larger kilns, or "calcaroni."

When the sulphur ceases to run from the kiln, the process is complete.
The residue is left to cool, which consumes from one to two months.
The cooling process could be accomplished in much less time by
permitting the air to enter the kiln, but this would be destructive to
vegetation, and even to life, consequent upon the fumes of the
sulphur. The greatest heat at a given time in a kiln is calculated to
be above 650 degrees Centigrade--that is, at the close of the process.
This enormous heat is generally allowed to waste, whereas it is
understood it could be utilized in many ways. A gentleman of the name
of Gill is understood to have invented a recuperative kiln, which
will, if generally adopted, utilize the heat of former processes
named. A ton of ore containing about 25 per cent. of sulphur yields
300 pounds of sulphur. This is considered a good yield. When it yields
200 pounds it is considered medium, and poor when only 75 pounds.
Laborers are paid 0.40 lire per ton for loading and unloading kilns,
and from thirty to forty hands are employed at a time. The keeper of a
kiln receives from 2 to 2.50 lire per day.

Notwithstanding the "calcarone" has many defects, it is the simplest
and cheapest mode of smelting, and is preferred here to any other
system requiring machinery and skilled labor to operate it.

The following are the principal furnaces in use here: Durand's;
Hirzel; Gill and Kayser's system of fusion; Conby Bollman process;
Thomas steam process of smelting; and Robert Gill's recuperative
kilns.

There are seven qualities or grades of sulphur, viz.:

1. Sulphur almost chemically pure, of a very bright and yellow color.

_Second Best._--Slightly inferior to the first quality; bright and
yellow.

_Second Good._--Contains 4 to 5 per cent. of earthy matter, but is of
a bright yellow.

_Second Current._--Dirty yellow, containing more earthy matter than
that last named.

_Third Best._--Brownish yellow; this tint depends on the amount of
bitumen which it contains.

_Third Good._--Light brown, containing much extraneous matter.

_Third Current._--Brown and coarse.

These qualities are decided by color, not by test. The difference of
price is from 3 to 10 francs per ton. Manufacturers prefer the third
best, because of its containing more sulphuric acid and costing less
than the sulphu