The original mode of preparing orchilla, that which was practised by the ancients, is said to have been lost, and many chemical experiments exhausted in vain for its recovery.  In 1300, however, it was rediscovered by a Florentine merchant, and from that period preserved as a profound secret, by the Florentines and the Dutch.  It appears that the Florentines were not satisfied with keeping the preparation of orchilla a mystery from the rest of the world, but that they endeavoured to lead all inquiry into a false channel, by calling it tincture of turnsole, desiring it to be believed, that it was an extract from the heliotropium or turnsole:  the Dutch also disguised it in the form of a paste, which they called lacmus or litmus.  The process is now, however, generally known, and simply consists of cleaning, drying, and powdering 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, accounted for, in this instance, by the political events which threw the trade out of its regular channels.