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These extremities, when pressed, give out a white unctuous fluid resembling milk, which has a sour taste. It was formely thought to be the seed and nutritious juice of the coral plant.

The substance of coral is hard as well in the sea, as when out. The red kind is red from the first, and it is a singular circumstance, that the ancients should have entertained these two erroneous opinions, which the most simple examination would have falsified.The central part or axis of the coral is hard, of a firm solid texture, even, and lamellated; and hence capable of taking the finest polish. This is inclosed by a paler coloured bark of a granulated texture, interspersed with holes in the form of stars with eight rays. In the coral of the largest size sometimes is found a kind of joint or union between the different pieces of which it is composed, these having the appearance of tubes of some length, lying one above the other. In the analysis of coral we obtain a small quantity of gelatinous animal matter, a large proportion of carbonate of lime, and a little iron. The different colours of this beautiful marine production seem to depend on the different degrees of oxidation of the iron, and various proportions of it in union with the animal matter. The discovery of polypi gave the clearest idea of the origin and growth of coral. These animals, the last in the scale of animated nature, form for themselves small nests sufficiently solid to shelter and protect them. These soft and delicate animals, surrounded by an element in a constant state of agitation, and exposed to the attacks of their numerous ener VOL. LIV.

mies, were instructed by nature to form for themselves a covering capable of resisting the percussion of the sea, and affording them a retreat in the moment of danger.

These coralligenous polypi are only a few lines in length; their bodies elongate and ramify into eight delicate threadlike branches around the mouth. These are the arms and legs of the animal, which it can extend and spread out at will to a considerable distance in search of its food. They are analogous to the horns of the snail. The curious manner of propagation of polypi, so different from that of other larger and more perfect animals, is well known; on examining minutely the gelatinous bodies of these polypi, a great number of grains, or little buds, are discernible, covering the surface; these elongate themselves, increase in thickness, diverge and spread in all directions, and become young polypi. Scarcely are these developed, before a new series of sprouts appears from their small bodies by the increase and growth of the small buds on their surface By this rapid succession the family is propagated in every direction, forming as it were a genealogical tree of existing generations. It is well known how, from the soft nature of their bodies, these animals are enabled to unite and engraft with each other in the same manner as plants; and one branch of these animalculæ so engrafted lives and regenerates another. Even one single animal may detach itself from the family tree, and establish on another spot a new family with its various branches. While large animals have bones for the support of the softer parts, and shell fish are pro2 K

tected

tected by their shells, the coralligenous polypi make use of a certain proportion of earth to incorporate with and give firmness to their form.

Immediately as a polypus has fixed itself on a hard body, it begins to lay the foundation of its future generation. If you only take some stones from the bottom of the sea round Sicily, you will find on them small branches of red coral, and round red spots, which are the first depositions of the coralligenous polypi. In the same way as the bones of the larger animals are formed by the gradual deposition of the earthy particles separated from their food by vessels adapted to this purpose, so is the covering of these polypi formed by the carbonate of lime mixing and encrustating with the gelatinous matter, which is so abundantly secreted by their delicate bodies, and gradually incases them except the mouth. If a branch of coral newly gathered is immersed in a vessel full of sea water, these animals are perceived issuing from the stellated holes, their mouths gradually appearing first, and then their silk-like arms extend, in this manner putting on the appearance of octopetalous flowers, by which the ingenious Count Marsigli was deceived.

The multiplication of polypi, of which I have treated, explains admirably the arboraceous form of coral, as also the increase of the branches detached from the trunk. I have before me a fine specimen of the antiphates, the black coral of the ancients, in which the extremity of a branch has united with the principal trunk, and the polypi are seen bedded in it.

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From what have seen, I think the term zoophyte inapplicable to coral; it is neither an animal plant, nor a plant animal : nor can it be called a zoolite; as it is certainly not a stony animal. It is with more propriety a polipaio; which, on account of its form, and to distinguish it from the other analogus works of polypi, might be called polipaio dendroide. In using this nomenclature, we must be careful not to adopt the false idea, that the polipaio resembles a wasp's nest; the wasps may at will leave their nests, but the polipaio is a part of the animal, from which it cannot be detached. Thus the polipaio dendroide is an accumulation of ramified polypi, incorporated with the solid substance, in the same manner as the shell of some animals and the bones of others. The above erroneous opinion cannot be entertained by any one, who observes, that in coral the gelatinous membrane of the polypus is continued into the solid earthy part, the same as in bones. Herissant has already pointed out this mistake.

It is to be inferred from the analogy of coral with bone, that, as it does not arrive at once at a state of maturity, but by degrees, its hardness must also be progressive. However probable this idea may be, it has not been confirmed by experience. I have particularly remarked the small quantity of iron obtained in the analysis of the red coral; I have always found it combined with the gelatinous animal substance in the state of oxide. Not to extend this paper too much, I shall omit the results of various experiments I have made; but they have led me

to

to conclude, that, the ferruginous substance is phosphate of iron, that is, the oxide of iron united with phosphoric acid, which it is well known gives the red colour to the blood of animals. The phosphate of iron therefore, which in animals has the property of giving the lively red colour to the blood, and even the vermilion hue to the skin, serves to colour the solid part of coral, and give it the brilliant sanguineous tinge.

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The first variety, as I have remarked, is esteemed the most perfect; it is more solid than the other kinds, of a finer and more compact texture, and hence takes a higher polish. In the other kinds, in proportion as the bright colour fades, these qualities gradually decrease, so that the white sort, which is the softest and lightest, is very unfit to be wrought, and takes but a trifling polish. The deficiency in the quantity of phosphate of iron diminishes the colour, and at the same time decreases the density of its texture; or perhaps the light texture by its porosity permits the water to wash away the colouring matter, and consequently that which would tend to bring it to perfect maturity...

To this may be attributed the peculiarities of some corals, in which the trunk is red, and the branches white; or the branches red within, and externally white; or the branches half white and half red, which is often seen in coralligenous productions; but the red part always proves of firmer texture than the others.

While naturalists have been employed in investigating the origin of coral, and the nature of its growth, each applying it to dif

ferent purposes; the fair sex, occupied by the natural desire of pleasing, have been much indebted to the brilliant colour and fine lustre of this marine production. Coral formed into beads is worn as an ornament of the neck and arms; and there is no doubt, that the lively colour of coral gives additional grace to a fine face and beautiful complexion, which cannot be obtained by the use of the precious stones, so that these can only be considered as ornaments of luxury and show. The ladies, who are always led away by fashion, because they consider it as depending on the existing taste of the other sex, laid aside this beautiful ornament, to load themselves with jewels brought from distant countries. Thus coral gave place to other ornaments, the rage of pleasing being only gratified by variety. Works of amber have latterly obtained a very high estimation from the softness of its substance and its transparency.

This substance, which for a time was in high repute, and which the discovery of the precious stones had almost thrown into oblivion has of late, by the accustomed versatility of capricious fashion, recovered its former value, and has rivalled in price even the orpaments composed of jewels.

When the value of female ornaments shall depend no longer on the price or scarcity, but on the effect they produce on the complexion, all will yield to the natural beauty of coral. Most certainly Galatea, emerging from the ocean, would select from the numerous offerings of the nymphs the lucid branches of the coral to adorn herself with, which would alone as2K 2 similate

similate with the roundness of her lips, and with the vermilion of her cheeks.

The working of coral consists in removing the outer bark, and exposing the interior solid and highly coloured part, which takes a fine polish. The coarse part of the bark being removed by the file, it is rubbed with tripoli powder, and lastly, with a metallic earth, which gives the polish. Some bring it to the finest polish imaginable by the use of the oxide of tin.

The ancients ornamented their swords, bucklers, and helmets with coral; this custom is still in vogue in some part of Asia, where coral is as much esteemed as in the time of Pliny. The soothsayers and priests of that age attributed many mystic properties to it; hence they were in the habit of wearing coral, as well from religious motives, as from regard to its beauty. Paracelsus recommends it to be worn round the necks of infants, as an admirable preservative against fits, sorcery, charms, and even against poison. Many other follies of that man are still prevalent, and of great credit with the common people; and it is very usual in the inland parts of Sicily, to see children wearing amulets of coral round the neck for the above purpose. In the cities it is worn in the shape of a horn, as a protection against the influence of evil eyes. It was even believed, that coral would drive away devils and evil

spirits; hence perhaps arose the custom of making crowns of it. Nor have the medicinal properties of coral been less exaggerated, as may be sufficiently seen in the writings of Pliny and Dioscorides. It

certainly may be considered as an absorbent; it is used in dentifrice powder, in the Alkermes for indigestion, and in the Troches of Carabe.

The Trapanese appear to have been the first who worked the coral, being induced thereto by the great quantity of it found in their seas. It is asserted, that Antonio Ciminello, a Trapanese, was the first who discovered the art of engraving coral. In the time of King Alphonso the coral fishery was so assiduously, and so advantageously pursued by the Trapanese, that the ministers of that king proposed to subject the fishery to a tax. In the last century, when it was again proposed, instead of a tax, which probably would have ruined this branch of industry, King Ferdinand instituted some very useful regulations in favour of it.

Beside forming necklaces and bracelets, the Trapanese have the art of engraving it in the same manner as they do amber and shells, and most certainly many of these works display great spirit, boldness, and grace in the execution, talents natural to the genius of the Sicilian nation.

USEFUL

USEFUL

PROJECTS AND IMPROVEMENTS.

ON THE MANAGEMENT OF THE ONION. By Thomas Andrew Knight, Esq. F.R.S. &c.

THE

HE first object of the Horticultural Society being to point out improvements in the culture of those plants, which are extensively useful to the public, I send a few remarks on the management of one of these, the onion; which both constitutes one of the humble luxuries of the poor, and finds its way in various forms to the tables of the affluent and luxurious.

Every bulbous rooted plant, and indeed every plant which produces leaves, and lives longer than one year, generates, in one season, the sap, or vegetable blood, which composes the leaves and roots of the succeeding spring; and when the sap has accumulated during one or more seasons, it is ultimately expended in the production of blossoms and seeds. This reserved sap is deposited in, and composes in a great measure, the bulb; and moreover the quantity accumulated, as well as the period required for its accumulation,varies greatly in the same species of plant, under more or less favour

Thus the

able circumstances. onion in the south of Europe acquires a much larger size during the long and warm summers of Spain and Portugal, in a single season, than in the colder climate of England; but under the following mode of culture, which I have long practised, two summers in England produce_nearly the effect of one in Spain or Portugal, and the onion assumes nearly the form and size of those thence imported.

Seeds of the Spanish or Portugal onion are sown at the usual period in the spring, very thickly, and in poor soil; generally under the shade of a fruit tree and in such situations the bulbs in the autumn are rarely found much to exceed the size of a large pea. These are then taken from the ground, and preserved till the succeeding spring, when they are planted at equal distances from each other, and they afford plants, which differ from those raised immediately from seed only in possessing much greater strength and vigour, owing to the quantity of previously generated sap being much greater in the bulb than in the seed. The bulbs, thus raised, often exceed considerably

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