occupy its place in the centre of the flame; neither does it, when there, enlarge the diameter of the flame, so as to prevent the access of air to its internal part. When its length is too great for the vertical position, it bends on one side; and its extremity, coming into contact with the air, is burned to ashes, excepting such a portiou as is defended by the continual afflux of melted wax, which is volatilized and completely burned by the surrounding flame. We see, therefore, that the difficult fusibility of wax renders it practicable to burn a large quantity of fluid by means of a small wick; and that this small wick, by turning on one side in consequence of its flexibility, performs the operation of snuffing upon itself, in a much more accurate manner than it can ever be performed mechanically.

Mr. Henry made some experiments on the light afforded by the combustion of different gases, and found, that it was apparently in the ratio of the oxygen that entered into combination with the hydrogen they contained. Thus, 100 parts of pure hydrogen gas required from 50 to 54 of oxygen; 100 of gas from oak, 42; from moist charcoal and from dried peat, each 50; from lamp oil 156; from coal 140; from wax 166; pure olifiant gas 210. Tallow is nearly on a par with oil. The production of light from the first four was so trifling, that they did not seem applicable to œconomical purposes.

LIGHT from plants. In Sweden a very curious phenomena has been observed on certain flowers by M. Haggern, lecturer in natural history. One evening he perceived a faint flash of light repeatedly dart from a marigold. Surprised at such an unconimon appearance, he resolved to examine it with attention; and, to be assured it was no deception of the eye, he placed a man near him, with orders to make a signal at the moment when he observed the light. They both saw it constantly at the same moment. The light was most brilliant on marigolds of an orange or flame colour; but scarcely visible on pale ones. The flash was frequently seen on the same flower two or three times in quick succession, but more commonly at intervals of several minutes: and when several flowers in the same place emitted their light together, it could be observed at a considerable distance. This phenomenon was remarked in the months of July and August at sunset, and for half an hour when the atmosphere was clear; but after a rainy day, or when the air was loaded with va

rious.

LIGHT house, a building erected upon a cape or promontory on the sea coast, or upon some rock in the sea, and having on its top in the night-time a great fire, or light formed by candles, which is constantly attended by some careful person, so as to be seen at a great distance from the land. It is used to direct the shipping on the coast, that might otherwise run a-shore, or steer an improper course, when the darkness of the night and the uncertainty of currents, &c. might render their situation with regard to the shore extremely doubtful. Lamplights are, on many accounts, preferable to coal fires or candles; and the effect of. these may be increased by placing them either behind glass hemispheres, or before properly disposed glass or metal reflectors, which last method is now very generally adopted. See BEACONS.

LIGHTFOOTIA, in botany, so named in honour of John Lightfoot, a genus of the Polygamia Dioecia class and order. Essential character: calyx four-leaved; corolla none female and hermaphrodite, stigma sessile; berry umbilicated, one-celled, with from three to six seeds. There are three species, all shrubs.

LIGHTNING. It is now universally allowed, that lightning is really an electriPhilosocal explosion or phenomenon.

phers had not proceeded far in their experiments and inquiries on this subject, before they perceived the obvious analogy between lightning and electricity, and they produced many arguments to evince their similarity. But the method of proving this hypothesis, beyond a doubt, was first proposed by Dr. Franklin, who, about the close of the year 1749, conceived the practicability of drawing lightning down from the clouds. Various circumstances of resemblance between lightning and electricity were remarked by this philosopher, and have been abundantly confirmed by later discoveries, such as the following: Flashes of lightning are usually seen crooked and waving in the air; so the electric spark drawn from an irregular body at some distance, and when it is drawn by an irregular body, or through a space in which the best conductors are disposed in an irregular manner, always exhibits the same appearance. Lightning strikes the highest and most pointed objects in its course, in preference to others, as hills, trees, spires, masts of ships, &c. so all pointed conductors receive and throw off the electric fluid more readily than those that are terminated by flat surfaces. Lightning is observed to take and follow the readiest and best conductor; and the same is the case with electricity in the discharge of the Leyden phial; from whence the Doctor infers, that in a thunder-storm it would be safer to have one's clothes wet than dry. Lightning burns, dissolves metals, rends some bodies, sometimes strikes persons blind, destroys animal life, deprives magnets of their virtue, or reverses their poles; and all these are well-known properties of electricity.

To demonstrate, however, by actual experiment, the identity of the electric fluid with the matter of lightning, Dr. Franklin contrived to bring lightning from the hea vens by means of a paper kite, properly fitted up for the purpose, with a long fine wire string, and called an electrical kite, which he raised when a thunder storm was perceived to be coming on: and with the electricity thus obtained, he charged phials, kindled spirits, and performed all other such electrical experiments as are usually exhibited by an excited glass globe or cylinder. This happened in June, 1752, a month after the electricians in France, in pursuance of the method which he had before proposed, had verified the same theory, but without any knowledge of what they had done. The most active of these were

Messrs. Dalibard and Delor, followed by M. Mazeas, and M. Monnier.

Nor had the English philosophers been inattentive to this subject. Mr. Canton, however, succeeded in July, 1752; and in the following month Dr. Bevis and Mr. Wilson observed nearly the same appearances as Mr. Canton had done before. By a number of experiments Mr. Canton also soon after observed, that some clouds were in a positive, while some were in a negative state of electricity; and that the electricity of his conductor would sometimes change from one state to the other five or six times in less than half an hour.

How it happens that particular parts of the earth, or the clouds, come into the opposite states of positive and negative electricity, is a question not absolutely determined: though it is easy to conceive that when particular clouds, or different parts of the earth, possess opposite electricities, a discharge will take place within a certain distance; or the one will strike into the other, and in the discharge a flash of lightning will be seen. Mr. Canton queries whether the clouds do not become possessed of electricity by the gradual heating and cooling of the air; and whether air suddenly rarefied may not give electric fire to clouds, and vapours passing through it, and air suddenly condensed receive electric fire from them. Mr. Wilcke supposes, that the air contracts its electricity in the same manner that sulphur and other substances do, when they are heated and cooled in contact with various bodies. Thus, the air being heated or cooled near the earth, gives electricity to the earth, or receives it from it; and the electrified air being conveyed upwards by various means, communicates its electricity to the clouds. Others have queried, whether, since thunder commonly happens in a sultry state of the air, when it seems charged with sulphureous vapours, the electric matter then in the clouds may not be generated by the fermentation of sulphureous vapours with mineral or acid vapours in the air. With regard to places of safety in times of thunder and lightning, Dr. Franklin's advice is, to sit in the middle of a room, provided it be not under a metal lustre suspended by a chain, sitting on one chair, and laying the feet on another. It is still better, he says, to bring two or three mattresses, or beds, into the middle of the room, and folding them double, to place the chairs upon them; for as they are not so good conductors as the walls, the light

ning will not be so likely to pass through them. But the safest place of all is in a hammock hung by silken cords, at an equal distance from all the sides of the room. Dr. Priestley observes, that the place of most perfect safety must be the cellar, and especially the middle of it; for when a person is lower than the surface of the earth, the lightning must strike it before it can possibly reach him. In the fields, the place of safety is within a few yards of a tree, but not quite near it. Beccaria cautions persons not always to trust too much to the neighbourhood of a higher or better conductor than their own body, since he has repeatedly found that the lightning by no means descends in one undivided track, but that bodies of various kinds conduct their share of it at the same time, in proportion to their quantity and conducting power. See Franklin's Letters, Beccaria's Lettre dell' Ellettricessimo, Priestley's History of Electricity, and Lord Mahon's Principles of Electricity.

Lord Mahon observes, that damage may be done by lightning, not only by the main stroke and lateral explosion, but also by what he calls the returning stroke, by which is meant the sudden and violent return of that part of the natural share of electricity which had been gradually expelled from some body or bodies, by the superinduced elastic, electrical pressure of the electrical atmosphere of a thunder-cloud.

The ancient notion of a thunderbolt, or, stony mass, falling at the stroke of lightning, seems to have obtained no small degree of force from the modern observations and researches concerning stones which have fallen from the atmosphere. See STONES, meteoric. From which it appears, that other substances as well as water are not

unfrequently condensed and precipitated from the air, and exhibit the most astonishing degrees of heat and electricity during

their condensation.

LIGNUM vita. The lignum vitæ tree is a native of the West Indies, and the warmer parts of America: there is also a species, a native of the Cape of Good Hope. It is a large tree, rising at its full growth to the height of forty feet, and measuring from fifteen to eighteen inches in diameter; having a hard, brittle, brownish bark, not very thick. The wood is firm, solid, ponderous, very resinous, of a blackish yellow colour in the middle, and a hot aromatic taste. It is so hard as to break the tools which are employed in felling it; and is, therefore,

seldom used as firewood, but is of great use to the sugar-planters for making wheels and cogs to the sugar-mills. It is also frequently wrought in bowls, mortars, and other utensils. It is imported into England, in large pieces of four or five hundred weight each, and from its hardness and beauty, is in great demand for various articles in the turnery ware, and for trucks of ship blocks. The wood, gum, bark, fruit, and even the flowers of this plant, have been found to possess medicinal virtues.

LIGULA, in natural history, a genus of the Vermes Intestina. Body linear, equal, long; the fore-part obtuse; the hind-part acute, with an impressed dorsal suture. There are two species, viz. L. intestinalis, L. abdominalis; the former is found in the intestines of the merganser and guillemot: about a foot long, and exactly resembling a piece of tape: of the latter there are, at least, eight varieties described as inhabiting the intestines of fish: they are found principally in the mesentery, emaciating the fish they infest, and causing them to grow deformed. When they escape from the body they penetrate through the skin: they are sometimes solitary, and sometimes gregarious, about half a line thick, and from six inches to five feet long.

LIGUSTICUM, in botany, lovage, a genus of the Pentandria Digynia class and order. Natural order of Umbellatæ, or Umbelliferæ. Essential character: fruit oblong, five-grooved on both sides; corolla equal, with involute entire petals. There are eight species, of which L. levisticum, common lovage, has a strong, fleshy, perennial root, striking deep into the ground, composed of many strong fleshy fibres, covered with a brown skin, possessing a hot ́ aromatic smell and taste. The leaves are large, composed of many leaflets, shaped like those of Smallage, but larger and of a deeper green; stems six or seven feet high, large and channelled, dividing into several branches, each terminated by a large umbel of yellow flowers. It is a native of the Alps, of Italy, the South of France, Silesia, &c.

LIGUSTRUM, in botany, privet, a genus of the Diandria Monogynia class and order. Natural order of Sepiariæ. Jasmineæ, Jussieu. Essential character: corolla four-cleft; berry four-seeded. There are three species, of which L. vulgare, common privet, is a shrub about six feet in height, branched, the bark of a greenish-ash colour, irregularly sprinkled, with numerous pro

minent points; branches opposite, the young ones flexible and purplish; leaves opposite, on short petioles, smooth on both sides; panicle about two inches in length, somewhat pyramidal; corolla white, but soon changes to a reddish-brown. Privet is found wild in most parts of Europe, and in Japan, in woods and hedges; it flourishes best in a moist soil.

LIKE quantities, or SIMILAR quantities, in algebra, are such as are expressed by the same letters, to the same power, or equally repeated in each quantity; though the numeral co-efficient may be different: thus, 4 a and 5 a áre like quantities; so also are 3 z2 and 9 z2; and likewise 5 bdy2 10bdy2. But 4a and 86 are not like quantities; nor are 4a and 4 a2.

LIKE figures, the same as SIMILAR figures. All like figures have their homologous lines in the same ratio. Like plane figures are in the duplicate ratio, or as the squares of their homologous lines or sides; and like solid figures are in the triplicate ratio, or as the cubes of their homologous sides.

LILIUM, in botany, lily, a genus of the Hexandria Monogynia class and order. Natural order of Coronaria. Lilia, Jussieu. Essential character: corolla six-petalled, bell-shaped, with a longitudinal nectareous line; capsule, the valves connected by cancellated hairs. There are eleven species, with many varieties, L. candidum, common white lily, has a large bulb, from which proceed several succulent fibres; it has a stout, round, upright stem, usually three feet in height; leaves long and numerous, smooth and sessile; flowers white, terminating the stem in a cluster, on short peduncles; petals within of a beautiful shining white, on the outside ridged, and less luminous. Native of the Levant.

LILLY (WILLIAM), in biography, a noted English astrologer, born in Leicestershire in 1602. His father was not able to give him further education than common reading and writing; but young Lilly being of a forward temper, and endued with shrewd wit, he resolved to push his fortune in London, where he arrived in 1620, and, for a present support, articled himself as a servant to a mantua-maker in St. Clement Danes. But in 1624 he moyed a step higher, by entering into the service of Mr. Wright, in the Strand, master of the Salters' Company, who not being able to write, Lilly, among other offices, kept his books. On the death of his master, in 1627, Lilly paid his addresses to the widow, whom he

married with a fortune of one thousand pounds.

Being now his own master, he followed the bent of his inclinations, which led him to follow the puritanical preachers. Afterwards turning his mind to judicial astronomy, in 1632 he became pupil, in that art, to one Evans, a profligate Welsh parson; and the next year gave the public a specimen of his skill, by an intimation that the King had chosen an unlucky horoscope for the coronation in Scotland. In 1634, getting a manuscript copy of the "Ars Noticia" of Cornelius Agrippa, with alterations, he drank in the doctrine of the magic circle, and the invocation of spirits, with great eagerness, and practised it for some time; after which he treated the mystery of recovering stolen goods, &c. with great contempt, claiming a supernatural sight, and the gift of prophetical predictions; all which he well knew how to turn to good advantage.

Meanwhile he had buried his first wife, purchased a moiety of thirteen houses in the Strand, and married a second wife, who, joining to an extravagant temper, a termagant spirit which he could not lay, made him unhappy, and greatly reduced his circumstances.

With this uncomfortable yoke-mate he removed, in 1636, to Hersham, in Surrey, where he staid till 1641; when, seeing a prospect of fishing in troubled waters, he returned to London. Here, having purchased several curious books in this art, which were found on pulling down the house of another astrologer, he studied them incessantly, finding out secrets contained in them, which were written in an imperfect Greek character, and, in 1644, he published his "Merlinus Anglicus," an almanack, which he continued annually till his death, and several other astrological works, devoting his pen, and other labours, sometimes to King Charles's party, and at others to that of the parliament, but mostly to the latter, raising his fortune by favourable predictions to both parties, at one time by presents, and at others by pen. sions. Thus, in 1648, the council of state gave him in money fifty pounds, and a pension of one hundred pounds per annum, which he received for two years, and then resigned it on some disgust.

By his advice and contrivance, the King attempted several times to make his escape from confinement; he procured and sent the aqua fortis, and files to cut the iron bars

of his prison windows at Carisbrook Castle; but still advising and writing for the other party at the same time. Meanwhile he read public lectures on astrology in 1648 and 1649, for the improvement of young students in that art; and, in short, plied his business so well, that, in 1651 and 1652, he laid out two thousand pounds for lands and a house at Hersham.

During the siege of Colchester, he and Booker were sent for thither to encourage the soldiers; which they did by assuring them that the town would soon be taken; which proved true in the event.

Having, in 1650, written publicly that the parliament should not continne, but a new government arise; agreeably to which, in his almanack for 1653, he asserted that the parliament stood upon a ticklish foundation, and that the commonalty and soldiery would join together against them. Upon which he was summoned before the committee of plundered ministers; but receiving notice of it before the arrival of the messenger, he applied to his friend Lenthal, the Speaker, who pointed out the offensive passages. He immediately altered them, attended the committee next morning, with six copies printed, which six alone he acknowledged to be his, and by that means came off with only thirteen days custody by the serjeant at arms. This year he was engaged in a dispute with Mr. Thomas Gataker.

In 1665, he was indicted at Hicks's Hall for giving judgment upon stolen goods, but was acquitted. In 1659, he received from the King of Sweden a present of a gold chain and medal, worth about fifty pounds, on account of his having mentioned that monarch with great respect in his almanacks of 1657 and 1658.

After the Restoration in 1660, being taken into custody, and examined by a committee of the House of Commons, touching the execution of Charles I., he declared that Robert Spavin, then secretary to Cromwell, dining with him soon after the fact, assured him, it was done by Cornet Joyce. The same year he sued out his pardon, under the broad seal of England, and afterwards continued in London till 1665, when, upon the raging of the plague there, he retired to his estate at Hersham. Here he applied himself to the study of physic, having, by means of his friend Elias Ashmole, procured from Archbishop Sheldon a licence to practise it, which he did, as well as astrology, from thence till the time

of his death. In October, 1666, he was examined before a committee of the House of Commons, concerning the fire of London, which happened in September that year. A little before his death he adopted for his son, by the name of Merlin Junior, one Henry Coley, a tailor by trade; and at the same time gave him the impression of his almanack, which had been printed for thirty-six years successively. This Coley became afterwards a celebrated astrologer, publishing in his own name almanacks and books of astrology, particularly one entitled "A Key to Astrology."

Lilly died of the palsy in 1681, at seventynine years of age; and his friend Mr. Ashmole placed a monument over his grave in the church of Walton upon Thames.

Lilly was the author of many works. His "Observations on the Life and Death of Charles, late King of England," if we overlook the astrological nonsense, may be read with as much satisfaction as more celebrated histories, Lilly being not only very well informed, but strictly impartial. This work, with the lives of Lilly and Ashmole, written by themselves, were published in one volume 8vo. in 1774, by Mr. BurHis other works were principally as

man.

follow.

1. Merlinus Anglieus, junior. 2. Supernatural Sight. 3. The White King's Prophecy. 4. England's prophetical Merlin: all printed in 1644. 5. The starry Messenger, 1645. 6. Collection of Prophecies, 1646. 7. A Comment on the White King's Prophecy, 1646. 8. The Nativities of Archbishop Laud and Thomas Earl of Strafford, 1646. 9. Christian Astrology, 1647: upon this piece he read his lectures in 1648, mentioned above. 10. The third Book of Nativities, 1647. 11. The World's Catastrophe, 1647. 12. The Prophecies of Ambrose Merlin, with a Key, 1647. 13. Trithemius, or the Government of the World by presiding Angels, 1647. 14. A Treatise of the Three Suns seen in the Winter of 1647, printed in 1648. 15. Monarchy or no Monarchy, 1651, 16. Observations on the Life and Death of Charles, late King of England, 1651; and again in 1657, with the title of Mr. William Lilly's true History of King James and King Charles I., &c. 17. Annus Tenebrosus, or the Black Year. This drew him into the dispute with Gataker, which Lilly carried on in his Almanack in 1654.

LIMAX, in natural history, the slug. Body oblong, creeping, with a fleshy kind