which it withdraws in proportion to the number of eggs: after this work is performed, it foon dies, though it fill adheres to its pofition, rendering a further fervice to its progeny, and shielding them from the inclemency of the weather or the hoftile attacks of an enemy. In a good feafon they multiply exceedingly, having from 1800 to 2000 eggs, which produce the fame number of animalcules. The ancients knew them to be infects, for Pliny fays, "Coccum ilicis celerrime in vermiculum fe mutans." Lib. 24. fect. 4. When obferved with the microscope in July or Auguft, we find that what appeared as duft, are fo many eggs, or open capfales, as white as fnow, out of each of which iffues a gold coloured animalcule, of the fhape of a cockroche, with two horns, fix feet, and a forked tail.

Mr. De Reaumur has placed the kermes in the clafs of gall infects, on account of the analogy in their mode of propagation, and immoveable form, continuing even after death, like the other fpecies of this clafs, found upon different trees, appearing only like galls, or excrefcences, to the molt accurate naturalifts: therefore they could not be more properly named, than gall infects. There are of them of different fhapes and fizes, but that of the cofcoxa or carraca (the kermes) is of a spherical figure, about the fize of a juniper berry. It is found most plentifully on the oldest and loweft trees, and when the kermes are gathered near the fea, they are larger and give a brighter colour than thofe in any other places.

There are several fpecies of galls

difcovered on different trees and plants of Spain, though they only make ufe of thofe gathered on oaks, either for dying, or any other purposes; fuch are those, from the Levant, called Aleppo galls, which were generally made ufe of, till it was difcovered by frequent experiments, that the new ingredient called dividivi was preferable, being a fruit from the province of Carracas, and Maracaybo, in South America.

The great mystery which hitherto had not been difcovered, by those naturalifts who knew how to diftinguifh the gall infect from the galls, was to inveftigate their mode of propagation: Mr. de Reaumur affures us, that from frequent obfervations it appeared to him, that there are both male and female, but that fome which are extremely fmall, transform themselves into gnats, while others, growing larger, depofit their eggs, without any transformation; from which, and their analogy with the others, he concluded, that the fmall gnats with wings, though large in comparifon with their body, and striped with a beautiful crimson, were the males of the gall infect which he obferved with the help of a microfcope, feeing how they fecundate the females, before they affume a globular form towards March; but this happens when it is fcarcely ever noticed, and in fo fingular a manner, that a common obferver would never imagine such an event to have happened, or even fuppofe, that the males which he faw frifking about, had the leaft connexion with the females; but on the contrary, were small gnats which accidentally light upon the fame boughs; if to this obH 4

fervation

fervation we add, that as the new kermes which come forth in June, remain fmall without engaging our attention till March enfuing, when they begin to fwell without any appearance of animal life, it will not be thought fo extraordinary, that they have been generally held as a vegetable production. In Languedoc, and Provence, the poor are employed to gather the kermes, the women letting their nails grow for that purpofe, in order to pick them off with greater facility.

The custom of lopping off the boughs is very injudicious, as by this means they deftroy the next year's harveft. Some women will gather two or three pounds a day, the great point being to know the places where they are most likely to be found in any quantity, and to gather them early with the morning dew, as the leaves are more pliable and tender at that time, than after they have been dried and parched by the rays of the fun; trong dews will occafionally make them fall from the trees fooner than ufual: when the proper feafon paffes, they fall off of themfelves, and become food for birds, particularly doves. Sometimes there will be a fecond production, which is commonly of a lefs fize with a fainter tinge. The first is generally found adhering to the bark, as well as on the branches and talks; the fecond is principally on the leaves, as the worms choofe that part where the, nutricious juice preferves itfelf the longeft, is molt abundant, and can be most eafily devoured in the fhort time that remains of their existence, the bark being then drier and harder than the leaves.

The people of Hinojos, Bonares, Villalba, and other parts of the kingdom of Seville, dry it on mats in the fun, ftirring it about, and feparating the red duft, which is the fineft part, and being mixed with vinegar, goes by the name of Paftel. The fame is done with the hufks; but thefe have but half the value of the dust.

There is no doubt, but if this branch of industry was more closely attended to, there is yet room for improvement, and the kermes would give a brighter colour, fimilar to that obtained from the cochineal, likewise an infect found in the Mexican woods on a plant called nopal by the Americans, and tuna by the Spaniards; being the opuntia maxima folio obtufo rotundo of Sir Hans Sloane, and the cactus opuntia of Linneus,

It is remarked that thofe plants which are cultivated by art, give a much finer cochineal, known by the name of meftica, fo called from the quantities collected of it in the diflrict of Meteca, in the province of Honduras *.

But neither the cochineal, the kermes, or any fimilar production,

would

Eaft-Indies, they thought to folve the difficulty, by faying it proceeded from the incineration of woods, which had impregnated the earth with this fixed alkali, the bafis of faltpetre; fo that I had been led to beliove, it was formed by certain combinations, that took place in the act of combuftion: but I foon found my error, when' I had feen the method of making faltpetre in the different provin ces of Spain. I have now evident proofs that the bafis of nitre really exifts in the earth and in plants, the fame as in the Soda of Alicant. Let thefe learned gendemen come to Spain, they may convince themselves of this truth, and fee faltpetre with its alkaline bafis, in the manufactures of Caftile, Aragon, Navarre, Valencia, Murcia, and Andalufia, where it is made without the affiftance of vegetable matter; fometimes throwing in a handful of afhes of mat. weed, merely to filter the lye of earth, and though they often meet with gypfeous tone in the neighbourhood of their works, yet they make excellent faltpetre by boiling the lixivium of their lands only, in which they do not find an atom of gyplum; confequently they have gunpowder in Spain, without being indebted for its fixed alkali, to the vegetable kingdom, and without the visible or fentible converfion of the vitriolic acid of gypfum into the

nitrous.

Having thus difcovered in Spain a perfect fixed alkali in the earth, I pursued my obfervations on other falts, and vegetable productions, and after many reflections and experiments, I difcovered that fimilar fixed alkalies, many oils, and neutral falts, proceed from differ

as

ent combinations of the air, earth, and water, with fuch matters the air conveys in a diffolved state, and that these three elements, rifing, falling, and meeting, combine together, and form new bodies in the organs of vegeta tion.

Those who are verfed in phyfics, agree, that all the fubftances of the very globe we inhabit, confit of the combinations of fire, water, earth, and air; why then. deny them the power of combin ing, in the living organs of plants? when we fo often perceive in them, the faculty of changing, and transforming productions in the kingdom of nature. In proof of it, we find that many cruciformed plants give, by analyfis, the fame volatile alkali as animals, notwithstanding that their tubes are fimilar to the eye with those that give acids.

Some plants have their roots fo small, and yet their branches, leaves, and fruit so ponderous, that it appears impoffible, fo inconfiderable a root fhould draw fufficient nurture out of the earth for fuch various purposes. It feems therefore, that the ambient air, containing many diffolved bodies, penetrates into the plants, and combines in the vegetative tubes, forming thofe fubftances discovered by analyfation.

I have frequently feen water melons in Spain weigh from twenty to thirty pounds, with a ftem of only two or three ounces, fo great was the increase of the fibrous and tubulous fubftance of thofe plants, owing to the watery particles they imbibed from the air. It should feem then, that many plants draw their principal fupport from the air, water, and a small portion of

earth,

earth, combined by the imperceptible labour of the vegetative tubes, and veffels of air, which convert thofe matters into the products we contemplate, and taste ; many plants producing all thefe effects in water only; and we find that mint, and other odoriferous plants whofe roots grow in water, and in the air, give the fame fpiritus rector, and oils, as thofe that grow in the earth.

Botanifts know very well that thofe aquatic plants that fpring up from the bottom of waters have, with a very trifling deviation, the fame properties and qualities in the frozen regions, as in fultry and parching climates, and that their acrimony, caufticity, infipidity, and coolnefs, are invariable.

The experiments made by Van Helmont on the willow-tree, making it grow in water and a fmall portion of dried earth, fhew how much air, and water, added to the internal labour of plants, contribute to vegetation.

In the memoirs of the French academy of sciences, we find experiments of a celebrated chemift, to prove the existence of three neutral falts, in the extract of bor. rage. If he had gone further, and proved that one of thefe three falts, exifted in the earth, which produced the borrage, he would have illuftrated the fyftem of phyfics, and cleared up the point I am fpeaking of. The fame memoirs mention another academician, who reared an oak for many years, only with water, the confequences of which speak for themselves.

There are millions of firs about Valladolid, and Tortofa, replete with turpentine, and growing in a fmall portion of earth, and great

7

quantity of fand, in which it would be difficult to prove that the thousandth part of the turpentine, fo plentifully produced by thefe trees, had exifted; of courfe, it must be owing to channels of air, connected with the tubes of vegetation.

The conductory veffels of the wormwood of Granada, convey a bitterness to the very juice of the fugar cane, which grows by its fide; the foil of the king's botanic garden at Madrid, is of one equal kind, for all the different plants that are reared there; yet fome produce a wholefome fruit, while others near them, are poisonous; and one, with fixed alkali, will thrive clofe to another, full of volatile alkali.

The mountains and vallies of Spain, as well as the gardens, are full of aromatic plants, yet I do not know that any body has ever extracted by analyfis, any aromatic water, or volatile oil, from any uncultivated land.

The variation of foil, or culture, may alter the form of plants, change the luftre of their drapery, or give additional flavour to their fruit, but it can never change their effence and nature. In proof of this, it is known, there is only one indigenous tulip in Europe (I found it in flower near Almaden), it is fmall, yellow, and ugly, appearing only in the fpring. Gardeners may invent modes of cultivation, try all the climates of Europe, they may produce larger tulips with brighter colours, but they all will be inodorous; and the little tulip of Spain will give, by analyfis, the very fame product as duct as the most fuperb of the eaft, whose beautiful garment in

common