is iron.

The workmen commence by melting the ore in a reverberatory furnace of small size, and when the bath is full, they throw in 28 per cent. of old iron. In a little time, the sulphur passes from the lead to the iron, leaving the former metal free, which occupies the bottom of the basin. By this means, the same quantity of ore is reduced as in the first described process, with the advantage, too, of a considerable saving of time, and with one half of the labor; but it is attended with the complete loss of the iron, which, in some districts, however, is so cheap as to be of no consideration. England produces about half the lead of Europe; the Hartz, Austria, Prussia and their dependencies nearly all the remainder. The lead mine of Galena, in Illinois, yielded, in 1829, about 6000 tons of lead.-It is pretty certain that both lead and tin were employed, in extremely remote ages, in the fabrication of arms, and, above all, in the ornamental parts of them. Homer also alludes to the practice of putting leaden balls at the end of fishing-lines. The custom of writing on lead mounts also into very great antiquity. Frontinus and Dio Cassius assure us that the consul Hirtius, besieged in Modena, wrote upon a leaf of lead, respecting his situation, to Decius Brutus, who replied by the same means. Pausanias speaks of certain books of Hesiod written upon sheets of lead; and, if we may believe Pliny, even public acts were consigned to volumes or leaves of the same material. The poets make frequent allusion to leaden coins. Ficorini, in his Piombi Antichi, has collected and represented a vast number of monuments of this kind. Caylus conceived them to be all Roman; and thus, according to that writer, those even which represent Egyptian divinities, or are inscribed with Greek characters, are yet to be referred to the times of the Roman emperors. Statues of lead are very rare.

Lead; an instrument for discovering the depth of water. It is composed of a large piece of lead, from seven to eleven pounds in weight, and is attached, by means of a strap, to a long line, called the lead-line, which is marked at certain distances, to ascertain the fathoms.To heave the lead, is to throw it into the sea in a manner calculated to produce the desired effect.-Deep-sea lead; a lead of a larger size, being from 25 to 30 pounds weight, and attached to a much longer line than the former, which is

called a hand-lead.

LEENA; an Athenian hetæra (q. v.), mis

tress of Aristogiton. Being privy to the conspiracy of Harmodius and Aristogiton against the Pisistratidæ, when examined on the subject, she hit off her tongue, that she might not be able to speak. A statue was erected by the side of those of the tyrannicides, in honor of her, representing a lioness without a tongue, by the side of which was an image of Venus, whose priestess she was.

LEAF. As it is impossible to give an entirely satisfactory definition of what is meant by the word plant, or animal, so it has equally defied the exertions of naturalists to give a distinct definition of leaf. Leaves are the part of the vegetable world in which vegetable life manifests itself most strongly. Light and air, which so essentially influence the vegetable kingdom, act chiefly on the leaves; and, in relation to the air, leaves have been compared to the animal organs of respirationto lungs placed externally. They are also organs of nutrition, particularly on the lower surface. The same formation which prevails in the trunk, branches and roots, has been recognised in leaves, only that what in the former is annular and concentric, in the latter is spread out over an extended plane surface. The spiral vessels and sap vessels, which are observable in the leaf-stalk, are also partly to be traced in the leaf, and form the nerves and veins, which may be considered as the skeleton of the leaf. The spaces between them are filled with a cellular substance, covered by a soft, yet firm cuticle. The cellular substance and the cuticle are different on the upper and the lower surfaces; and, however various the form of the leaves, much conformity always exists in this respect, and is intimately connected with the life of the plant. The cellular substance is particularly filled with sap, generally of a green color. The cells of the upper surface are commonly disposed lengthwise; those of the lower surface, breadthwise; both commonly destitute of sap. The pores, which are generally only on the lower surface (except in plants whose leaves lie on the water, or close on the ground), serve to transmit the air to the internal parts of the plant; but in some plants they are not discernible, even in some of the more perfect kinds, particularly if the sap is not green. The leaf changes whatever passes through it into the plant from without, or from the plant; and so essential is the influence of light upon vegetable life, that the gaseous substances given out by plants, in the sun, or in the shade,

or by night, are chemically different. Sound and green leaves, in the sun, exhale oxygen and absorb carbonic acid gas; but by night, or in the dark, they give out carbonic acid gas, and absorb oxygen from the air: sickly plants, and those whose leaves are not green, do this in the sun. The green color, the almost universal hue of plants, is so intimately connected with light, that young plants do not begin to assume this color until they come into the light. The importance of leaves to plants is shown by the fact that no plant can grow, nor form blossoms, nor fruits, if deprived of leaves. When fruit has arrived at a certain degree of maturity, it may, indeed, be ripened more rapidly by depriving the plant of its foliage; but this only proves a diseased state. The fine hairs with which leaves are covered, and which sometimes become bristles, contribute considerably to the exhalation and absorption of air and moisture; so that a plant often owes its nourishment to the atmosphere more than to the ground; and many plants exhale much more aqueous matter than, on the highest estimation, they can receive from the ground. The leaves, moreover, have often an important part in the secretion of oily or other substances. There are whole orders of plants, consisting almost entirely of leaves, as certain mosses, heaths, and others, in which the leaf gives place almost entirely to the stem, so that an intermediate formation between the two is presented, as in the cactus, euphorbia, stapelia, &c. In many cases, the leaf proceeds only from the joints of the stem, as in the grasses; and, in this case, it retains much of the nature of the stem. No part of the plant is capable of such an immense variety of forms as the leaf, the description of which would exceed our limits. The leaves form an important characteristic in the subdivision of plants. They are divided into simple and compound, the latter class consisting of those in which several leaves are supported on one footstalk; and their various subdivisions are formed on the form 1. of the apex; 2. of the base; 3. of the circumference; 4. of the margin; 5. of the surface: 6. on their position; 7. their substance; 8. their situation and position; 9. their insertion; 10. their direction. The lobe of a leaf is the segment around the apex.-We will add here some interesting items of a memoir on the structure of leaves, read quite lately by M. Adolphus Brongniart, before the academy of sciences at Paris. The author states that the leaves of plants that live in the air have a

totally different structure from those that are completely submerged, and that this difference in the structure of organs is in direct relation to the two principal functions of leaves-respiration and transpiration. In leaves exposed to the air, the surface of the leaf is covered by an epidermis of uncertain thickness, formed of one or more layers of colorless cellules, closely packed together. This membrane is pierced with the pores usually known by the name of stomata. The doubts that have been entertained of the existence of perforations in these stomata, M. Brongniart thinks he has removed, and that it is certain that, in the centre of each stoma, is an opening by which the outer air communicates with the parenchyma. The parenchyma is evidently the seat of respiration; for it is the part that changes color in exercising this function, which becomes green by the absorption of the carbon of the carbonic acid of the atmosphere, and which is discolored again, in darkness, by the combination of the carbon of its juices with the oxygen of the air. This parenchyma differs entirely from that of other organs, by the numerous irregular cavities that it contains, which communicate with each other and the outer air by means of the openings of the stomata. It is into these cavities, in the cavernous parenchyma of aerial leaves, that the atmospheric air penetrates, when it is absorbed by the surface of the utricles of the parenchyma, that are distended with the fluids which seem to nourish the plant. According to M. Brongniart, aquatic leaves, if submerged, differ in being completely destitute of epidermis. It is not alone stomata that they want, as has long been known, but the epidermis also. There are none of the cavities that abound in the parenchyma of aërial leaves, but, on the contrary, the cellules of the tissue are compactly fastened together, without any interstice, and the air, dissolved in the water, can only act on their outer surface. For this reason, the proportion borne by this surface to the whole mass of the leaf, is unusually great. The leaves, from want of epidermis, dry up quickly when exposed to the air, and can only exist in water, or a very humid atmosphere. Hence the author concludes that the epidermis, is destined to protect aërial leaves against too rapid evaporation, and the stomata, or pores, of this epidermis become necessary to maintain a communication between the atmosphere and the parenchyma.

LEAGUE; a measure of length, containing more or fewer geometrical paces,

according to the different usages and customs of countries. A sea league contains 3000 geometrical paces, or three English miles. The French league sometimes contains the same measure, and, in some parts of France, it consists of 3500 paces. The mean or common league consists of 2400 paces, and the little league of 2000. Twenty common Spanish leagues make a degree, or 694 English statute miles. The German league (meile) contains four English geographical miles. The Persian league is also equal to four such miles, pretty near to what Herodotus calls the length of the Persian parasang, which contains 30 stadia, eight of which make a mile. (See Mile.)

LEAGUE. Those political connexions which have been called alliances, since the French language has become the fashionable language of Europe, were denoted, during the prevalence of Spanish and Italian influence, from 1500 to 1650, by the term league (from the Spanish word liga). To some alliances this term is more distinctly applied. Among these are the league of Cambrai, formed, in 1508, between Louis XII, king of France, the German emperor Maximilian, and Ferdinand of Spain, for the purpose of humbling the republic of Venice, and which was joined, in 1509, by pope Julius II. This league was dissolved in 1510, as many similar ones have been, in consequence of mutual distrust, and was succeeded by the liga santa, or holy league, between the pope, Maximilian, Ferdinand and Venice. The object of this was to compel Louis XII, whose allies had now become his enemies, to renounce his conquests in Italy; which object was gained. This was the first example of a holy league, which name was derived from the participation of the pope. Thirty years afterwards, a holy league was formed in Germany. For when the principal Protestant princes in Germany united, in 1536, to form the union of Smalkalden, in order to protect their common faith, and withstand the emperor Charles V, the Catholic princes assembled at Nuremberg, in 1538, to take measures for the support of their own faith, and to oppose the designs of the Protestant princes; and, as their league had the protection of the Catholic church for its object, they termed it the holy league. A fourth league, also, called the Catholic, was formed by Henry, duke of Guise, in 1576, against Henry III of France. Its ostensible object was the support of the Catholic religion; but the duke of Guise had further views of his own. As Henry

III was without male heirs, the throne, at his death, would pass to the Protestant prince Henry of Navarre; to exclude whom, and to obtain the throne for himself, were the real objects of the duke of Guise. His great popularity seemed to render the accomplishment of his design easy. The example given by Paris in his favor was followed by all the provinces. The league was sanctioned by the pope and the king of Spain. In 1588, the duke of Guise was murdered at Blois, with his brother Louis, the cardinal, at the king's instigation. The league then declared the throne vacant, and named the third brother, Charles, duke of Mayenne, governor-general of the kingdom. Henry III now sought relief in the camp of his former enemy, Henry of Navarre. He was there assassinated in 1589. The war was then pursued by the league against Henry of Navarre, till it was ended, in 1594, by his uniting himself to the Catholic church; and the next year the league was dissolved. We find a fifth league, in Germany, in the seventeenth century, also termed Catholic. The peace of 1555 had not sufficiently restrained the Protestants, and had taken too much from the Catholics. Both parties regarded each other with distrust. The one was accused of encroachments; the other, of unreasonable pretensions. As Henry IV of France was ready to support the Protestant princes in any manner, for the purpose of humbling the house of Austria, these princes, excited by the injuries inflicted upon the Protestant town of Donauwerth, assembled in 1608, to form a union for their protection. The Catholic princes now took the same steps as after the union of Smalkalden: their association (1610) was also hastened by the disputes respecting the succession of JuliersCleves. The principal German princes laid claim to the possessions of John William, duke of Juliers-Cleves-Berg, &c., who had died, in 1609, without heirs. Henry IV supported the Protestant princes: a league was therefore formed, by the Catholic princes, at Wurtzburg, in 1610, at the head of which was Maximilian, duke of Bavaria. The unexpected death of Henry IV prevented their coming at once to action; but the union and the league kept up a vigilant opposition to each other till the breaking out of the 30 years' war. The head of the union, Frederic, elector-palatine, became king of Bohemia; and then the two parties took the field. An accommodation was at last effected at Ulm, July 3, 1620, by means of the united French, Spanish, Austrian