ering the plant, which, when mixed with half
its weight of pearl ash, is moistened with human urine, and then
allowed to ferment: the fermentation, we are informed by Professor
Burnett, "is kept up for some time by successive additions of urine,
until the colour of the materials changes to a purplish-red, and
subsequently to a violet or blue. The colour is extremely fugitive, and
affords a very delicate chemical test for the presence of an acid. The
vapour of sulphuric acid has been thus detected as pervading to some
extent the atmosphere of London."
I understand--and for some valuable particulars I here beg to tender my
acknowledgments to Mr. John Aylwin, merchant of London--that the great
object obtained from this vegetable dye, is the production of a red
colour, without the aid of a mineral acid. But the utility of the
orchilla is not confined to the purposes of manufacture. It has been
successfully employed as a medicine in allaying the cough attendant on
phthisis, and in hysterical coughs. It is also variously used in many
productions, where its splendid hue can be rendered available, and
imparts a beautiful bloom to cloths and silks.
The introduction of the weed into England came originally through the
Portuguese. The Cape de Verd Islands having long been a possession of
the crown of Portugal, orchilla became a royal monopoly, and was
transmitted in considerable quantities to Lisbon, where it was sold by
public auction; from Lisbon it gradually found its way to England,
France, Germany, &c. The recent political contest in Portugal, caused a
total suspension of the shipment of orchilla at the islands. About six
months ago, there were two cargoes at Bona Vista waiting for orders,
one of them (a vessel of about 66 tons) put to sea, and arrived safe at
Lisbon only a few weeks before Admiral Napier's naval victory. When the
news of the result of that battle reached the island, the holders of
the remaining cargo proposed to hand it over for a consideration to
certain parties in the interest of Donna Maria, and it was accordingly
consigned to a Portuguese house in London. The vessel in which it was
sent was called the Saint Anne, of 60 tons, and sailed under British
colours: the cargo consisted of 564 bags,[8] each containing 2 cwt.,
and the whole sold for 15,000L. I mention this circumstance as an
occurrence worth being recorded; the arrival of a vessel to England
direct from the islands being a great novelty, accoun
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