The
greatest difficulty the miners have to encounter is water. This
element, which is so abundant in Ceylon, is the great drawback to the
sucessful quarrying of plumbago. Buckets are resorted to, and latterly
the more enterprising miners have taken to pumps. The amount of manual
labour required to drain a pit of sixty by eigty and from forty to
fifty feet deep must, therefore, be very great. But nevertheless, it is
done, and hence it is that miners seldom make anything beyond a small
profit in their speculation. It is a mistake to suppose that plumbago
is found on the surface. One seldom meets with a vein, or "illeme," as
the natives call it, excepting below thirty feet, the layer seldom
exceeding two feet in thickness. Of course, there is great rejoicing
when a good layer is found, and picked men are sent down with long
pointed knives to break it up into as large blocks as they can
conveniently do, which are placed in closely-plaited baskets, and the
coolies have to take them to the store-room over the slippery steps.
When perfectly dry, the pieces are picked, soaked, and sized, and sent
to Colombo, the dust of course, which preponderates, being separately
packed. It is hard to give a description of a plumbago mine. It is a
iarge hole, if we may so call it, divided into compartments with
flights of steps like galleries. The scene is very picturesque when the
human hive are at work. The plumbago pit at Pellepittiagode in Pasdom
Korale is the largest we ever saw, and we are told the largest in the
island. Plumbago was first discovered there some fifty years ago, and
the proprietors worked at it by fits and starts, and latterly realised
a handsome profit. The pit now is as large as a little lake, and quite
deep enough for a vessel of four hurdred tons burthen to anchor safely
in. The large prices which plumbago realised latterly has given an
impetus to the trade. The royalty has been raised from 14s. to 16s. the
ton, notwithstanding which it still flourishes. We fear there will be a
great falling off this
year owing to the unsatisfactory state of the market in England. If
modern art can only be brought to bear on tl^e quarrying operations,
proprietors will, we are certain, make a handsome profit in the speculation.—"Ceylon Examiner."
A VISIT TO THE WORKS OF THE PATENT
PLUMBAGO CRUCIBLE COMPANY.
By J C. Brou'gi*
From the "Technologist," No. XLVI., Vol. 4, May 1S64.
Crucibles have been in use for melting and refining metals from that
distant point of time when man exchanged his stone hatchet and bone chisel
for implements of bronze. The earliest melting-pots were doubtless made of
the plastic and infusible substance clay, and there is no reason to suppose
that they differed essentially from the earthen crucibles now commonly used
in our foundries.
As
an instrument of scientific research, the crucible has held an
important position for at least a thousand years. It was constantly
used by the first alchemists, and may indeed, be truly styled the
cradle of experimental chemistry.* At the present time crucibles of one
form or another are extensively em-nloyed by the refiner of gold and
silver, the brass-founder, the melters of copper, zinc, and malleable
iron, the manufacturer of cast steel, the assayer, and the practical
chemist. They are made in many different shapes and sizes, and of many
materials, according to the purposes for which they are intended. For
certain chemical experiments requiring high temperature, vessels
* The word " Crucible," from the Latin crux—cruets, recalls the alchemical practice of making the vessel with the protective sign of the Cross.
