These islands, after being a considerable time lost and forgotten, were again discovered about the end of the fourteenth or the beginning of the fifteenth century, and since that time they have been much frequented by the Europeans. One of the first who endeavoured to obtain an establishment there, was John de Betancourt, a gentleman of Normandy, who in 1400, or, as others say, in 1417, landed on Lancerotta. Amongst the principal commodities which this gentleman and other Europeans brought back with them was archil, which was found there more beautiful and in greater abundance than anywhere else; and Betancourt enjoyed in idea the great profit which he hoped to derive from this article in commerce. Glass is surprised that the Europeans, immediately upon their arrival, sought after this lichen with as much eagerness and skill as they did after gold in America, though they were not so well acquainted with the former as the latter before the discovery of these new lands80. But as this is not true, the wonder will cease.
According to information procured in the year 1731, the island of Teneriffe produced annually five hundred quintals of this moss; Canary, four hundred; Forteventura, Lancerotta, and Gomera, three hundred each; and Fero, eight hundred; making in all two thousand six hundred quintals. In the islands of Canary, Teneriffe and Palma, the moss belongs to the crown; and in the year 1730 it was let by the king of Spain for one thousand five hundred piastres. The farmers paid then for collecting it from fifteen to twenty rials per hundred weight81. In the rest of the islands it belongs to private proprietors, who cause it to be collected on their own account. In the beginning of the last century a hundred weight, delivered on board at Santa Cruz, the capital of Teneriffe, was worth from only three to four piastres; but since 1725 it has cost labour amounting to ten piastres, because it has been in great request at London, Amsterdam, Marseilles, and throughout all Italy82. In the year 1726 this lichen cost at London eighty pounds sterling per ton, as we are told by Dillenius, and in 1730 it bore the same price.
Towards the end of the year 1730, the captain of an English vessel, which came from the Cape de Verde islands, brought a bag of archil to Santa Cruz by way of trial. He discovered his secret to some Spanish and Genoese merchants, who, in the month of July 1731, resolved to send a ship to these islands. They landed on that of St. Anthony and St. Vincent, where in a few days they obtained five hundred quintals of this lichen, which they found in such abundance, that it cost them nothing more than a piastre per cent. by way of present to the governor. The archil of the Cape de Verde islands appears larger, richer, and longer than that of the Canaries, and this, perhaps, is owing to its not being collected every year83. Adanson, in 1749, found also the greater part of the rocks in Magdalen island, near Senegal, covered with this lichen. Though the greater part of our archil is at present procured from the Canary and Cape de Verde islands, a considerable quantity is procured also from the Levant, from Sicily, as Glass says, and from the coast of Barbary; and some years ago the English merchants at Leghorn caused this lichen to be collected in the island of Elba, and paid a high price for it84.
Our dyers do not purchase raw archil, but a paste made of it, which the French call orseille en pâte. The preparation of it was for a long time kept a secret by the Florentines. The person who, as far as I know, made it first known was Rosetti; who, as he himself tells us, carried on the trade of a dyer at Florence. Some information was afterwards published concerning it by Imperati85 and Micheli the botanist86. In later times this art has been much practised in France, England, and Holland. Many druggists, instead of keeping this paste in a moist state with urine, as they ought, suffer it to dry, in order to save a little dirty work. It then has the appearance of a dark violet-coloured earth, with here and there some white spots in it.
The Dutch, who have found out better methods than other nations of manufacturing many commodities, so as to render them cheaper, and thereby to hurt the trade of their neighbours, are the inventors also of lacmus87, a preparation of archil called orseille en pierre, which has greatly lessened the use of that en pâte, as it is more easily transported and preserved, and fitter for use; and as it is besides, if not cheaper, at least not dearer. This art consists, undoubtedly, in mixing with that commodity some less valuable substance, which either improves or does not much impair its quality, and which at the same time increases its weight88. Thus they pound cinnabar and smalt finer than other nations, and yet sell both these articles cheaper. In like manner they sift cochineal, and sell it at a less price than what is unsifted.
It was for a long time believed that the Dutch prepared their lacmus from those linen rags which in the south of France are dipped in the juice of the Croton tinctorium89; and this idea appeared the more probable, as most of this tournesol en drapeaux was bought up by the Hollanders: but, as they are the greatest adulterators of wine in Europe, they may perhaps have used these rags to colour Pontack and other wines. It is however not improbable that they at first made lacmus of them, as their dye approaches very near to that of archil. At present it is almost certainly known that orseille en pâte is the principal ingredient in orseille en pierre, that is in lacmus90: and for this curious information we are indebted to Ferber91. But whence arises the smell of the lacmus, which appears to me like that of the Florentine iris? Some of the latter may, perhaps, be mixed with it; for I think I have observed in it small insoluble particles, which may have been pieces of the roots. The addition of this substance can be of no use to improve the dye; but it may increase the weight, and give the lac more body; and perhaps it may be employed to render imperceptible some unpleasant smell, for which purpose the roots of that plant are used on many other occasions.
Another kind of lichen, different from the roccella, which in commerce is known by the names orseille de terre, orseille d’Auvergne, is used also for the like purpose; but it contains fewer and weaker colouring particles. This species, in botany, is called Lichen Parellus (Lecanora Parella), and is distinguished from the roccella by its figure, as it grows only in a thin rind on the rocks. It is collected in Auvergne, on rocks of granite and volcanic productions, and in some parts of Languedoc; the greater part of it is brought from St. Flour. Its name, perelle, comes from an old Languedocian word pére (pierre, a rock); as roccella, afterwards transformed into orseille, is derived from rocca. The use of perelle is very trifling: the Dutch purchase it to make lacmus, perhaps on account of its low price. This lichen has been found also in Northumberland92 and other mountainous districts of Great Britain, but it is not collected there for any purpose.
MAGNETIC CURES
The external use of the magnet, to cure the tooth-ache and other disorders, is a remedy brought into fashion in modern times, but not a new discovery, as supposed by Lessing, who ascribes it to Paracelsus93. It was known to Aëtius, who lived so early as the year 500. That author says, “We are assured that those who are troubled with the gout in their hands or their feet, or with convulsions, find relief when they hold a magnet in their hand94.” He does not however give any proof of this from his own experience: and perhaps he doubted the truth of it. The above passage contains the oldest account known at present respecting this virtue; for the more ancient writers speak only of the internal use of the magnet.
It is evident therefore that this cure has not been discovered in later times, but that it has been preserved by the old physicians copying it from each other into their works. In like manner, many things are mentioned in the Materia Medica which were used or proposed by the ancients, but into the properties of which they never made sufficient inquiry.
Paracelsus recommended the magnet in a number of diseases, as fluxes, hæmorrhages, &c. Marcellus, who lived in the fifteenth