a supply of water in its cavity, till a dry season about two inches long, about the thickness of a rendered its expenditure necessary for the growth goose quill, but it can lengthen and shorten itself of the plant. It has been replied to this, that the very much. The bite of those leeches which are old leaves which require the least water, are fur- found in stagnant waters and marshes is said to nished with the largest supply, and that even in cause pain and inflammation; such leeches, therethe dryest season, this quantity is never entirely fore, as well as the horse leech, are not used, and exhausted. those are preferred which are taken in the summer Abandoning the opinions of Catesby and Lin-season, in waters having a clear sandy bottom. A næus, Dr. Smith has adopted another which seems | leech attaches itself to any substance to which it to have been founded on a single observation, made in the Botanic garden at Liverpool. An insect was observed by the gardener, drawing the flies which he could manage, into the tube of the leaf, where he supposed they were deposited as food for the aggressor, for it was found that the other leaves were also partially filled with water, and contained several dead or drowning flies. In most cases I am persuaded they are not forced into their hollow tomb, but having ventured too far upon the hairy border, they are unable to return, and at last fall into the water, where they perish. Here unquestionably they may be of use to the plant, by furnishing it with nourishment, which is absorbed by its hollow leaf, for the air evolved by decaying insects is favorable to vegetation. Dr. Smith therefore concludes that the design of this singular construction is to entrap and retain the small insects which become food for their larger companions, and nourishment for the plant which contains them: and he thinks it curious, that an European insect should find out an American plant in a hot house, in order to fulfil that pur-washed with soap and water, then with milk and pose.'

wishes to fix, by an apparatus constructed on the principle of a leather sucker, which it has at both ends; the one at the head being like a horse shoe, with a triangular mouth in the centre, and that at the other end being circular. When they fix on the body, they inflict a small wound of three little flaps, from which they suck blood until they are gorged, or till they are forced to quit their hold; this is best done by sprinkling on them a little salt. The cases are very numerous in which leeches are useful; and in children, where it is so difficult to get blood from a vein, leeches furnish an excellent resource. Leeches are useful in the various inflammatory diseases, as opthalmia, sore throat, rheumatism, toothache, inflammation of the bowels and uterus; in measles and scarlet fever, in chincough, in headache, in bruises, and in piles.

It is sometimes difficult to get leeches to fix; they should be kept hungry and taken out of the water for some minutes before they are to be used, and should be dried with a soft cloth immediately before they are applied. The part should be well

water, and wetted with blood or syrup, and if there It would be useless to find fault with this hy- be many strong hairs they should be shaved off. pothesis, or to mention others which have been A large leech will draw about an ounce of blood, defended with equal ingenuity, for none of them that is, about a table spoonful; and when they rest on the substantial basis of observation and come off, the bleeding may be encouraged to a experiment. It remains to be ascertained, whether considerably greater extent, by bathing the parts the water which the leaf contains is derived from with warm water, or by applying large poultices its root or from another source; whether it is pure, of bread and milk, or applying cupping glasses. or impregnated with any of the vegetable secre- It is sometimes difficult to stop the bleeding, and tions; whether the insects with which it is stored, the surgeon is sent for in great alarm, especially are forced into its cavity or become victims to their when leeches have been applied to young children. own temerity; whether they furnish birds and in- The bleeding may generally be stopped by proper sects with food, and whether the plant is less vig-pressure with a little lint or similar downy suborous, when all foreign substances are excluded from the cavity of its singular leaves. When these questions are all answered, there will be time enough to speculate; but until the subject is more thoroughly investigated, no theory can rest on a substantial foundation.

LECTURER. (In Ecclesiastical Law.) In England, a minister who preaches in the afternoon, and is usually paid by the people.

LEDGER. The chief book used in merchants accounts, wherein every man's particular account is kept; and also all the goods bought and sold are distinctly placed each by themselves, as debtor on the left hand page, and creditor on the right hand.

LEECH. A well known species of worm that lives in water, and is applied to various parts of the body to draw blood for the cure of disease.

There is only one species of leech used in medicine. It has a flat and slimy body, composed of rings, tapering towards the head; it is commonly

stance for a due length of time, though this is sometimes very difficult when there is no bone to press against; touching the wound with lunarcaustic will almost certainly succeed; but we must take care that the flowing blood do not wash the caustic down about the neighboring parts. Sometimes the wounds made by leeches give rise to a good deal of pain, swelling, and extensive inflammation. The best application is a cooling lotion of Goulard's Extract, or diluted spirits and water, or vinegar and water. If the pain and tension continue long, an emollient poultice of bread and milk will be useful.

'Salt has been thrown on the animal to make it disgorge the blood which it has sucked, but the leech is generally killed in the experiment. A more easy way to discharge the blood and save the animal is to hold it in the hand and gently squeeze it in a napkin from the head downward; the blood flows copiously from what may appear the anus, or through the ruptured extremity of the intestinal canal, and the worm is not essentially injured.'

Leeches are kept in a bottle half filled with pure spring or river water, covered with gauze or fine muslin. It is better not to put bran or any other substance into the water, but to change it pretty frequently. Leeches are said to be very sensible to the electrical changes of the atmosphere.

ray only, which falls in the direction of the axis of the lens, is perpendicular to the surface; the other rays falling obliquely, are refracted towards the axis, and they will meet beyond the lens at a point called its focus. The distance of the focus from the centre of the lens depends both upon the form of the lens, and upon the refractive power of the substance of which it is made; in a glass lens, both

LEGACY. In Law, a bequest or gift by testament of any personal effects; the person bequeath-sides of which are equally convex, the focus is ing is called the testator, and he to whom it is bequeathed the legatee.

situated nearly at the centre of the sphere of which the surface of the lens forms a portion; it is at the distance, therefore, of half the diameter of the sphere. The property of a lens which has a double concave surface is to disperse the rays of light. Instead of converging towards the ray, which falls on the axis of the lens, they will be attracted towards its thick edges, both on entering and quitting it, and will, therefore, be made to diverge. Lenses which have one side flat and the other convex or concave are less powerful in their refractions, than those which have been described. They are called plano-convex and plano-concave. The focus of the former is at the distance of the diameter of a sphere, of which the convex surface of the lens forms a portion. The last kind of lens is called a meniscus, being convex on one side and concave on the other, like the glass or crystal of a watch.

All the parallel rays of the sun which pass through a convex glass are collected in its focus, and the force of the heat there is to the common heat of the sun, as the surface of the glass is to the surface of the focus. If a lens four inches in diameter collect the sun's rays into a focus at the distance of twelve inches, the image will not be more than one tenth of an inch in diameter: the surface of this little circle is one thousand six hundred times less than the surface of the lens, and

LEGISLATURE. The body of men in a state or kingdom, invested with power to make and repeal laws; the supreme power of a state. The Legislature of Great Britain, consists of the house of lords and the house of Commons with the king, whose sanction is necessary to every bill before it becomes a law. The legislatures of most of the states in America, consist of two houses or branch-consequently the heat will be one thousand six es, but the sanction of the governor is required to give their acts the force of law, or a concurrence of two thirds of the two houses, after he has declined and assigned his objections.

LEMMA. A proposition in Mathematics, which serves to prepare the way for the demonstration of some theorem.

LEMON TREE. A variety of the citron tree, which grows in the south of Europe, and yields the fruit that bears the same name.

hundred times greater at the focus than at the lens. A globular decanter of water acts as a double convex lens, and furniture has been set on fire by leaving one incautiously exposed to the rays of the sun. A gentleman of London formed a burning glass three feet in diameter, and when fixed in its frame, it exposed a clear surface of more than two feet eight inches in diameter, and its focus, by means of another lens, was reduced to a diameter of half an inch. The heat produced by this was so great that iron plates were melted in a few seconds; tiles and slates became red-hot in a moment, and were vitrified, or changed into glass; sulphur, pitch, and other resinous bodies, were melted under water; gold was rendered fluid in a few seconds. But notwithstanding this intense heat at the focus, the finger might, without the smallest injury, be placed in the cone of rays within an inch of the focus. On bringing the finger nearer, a sensation was felt like that produced by a sharp lancet, and not at all similar to the pain LENS. Is a glass ground into such a form as occasioned by the heat of fire or a candle. Subto collect or disperse the rays of light which pass stances of a white color were difficult to be acted through it. They are of different shapes, from upon. Pure water in a clear glass decanter will which they take their names. If rays proceed not be warmed by the most powerful lens, but a from a radiant point distant as far as the sun, their piece of wood placed in the water may be burned divergency is so trifling that they may be consid- to a coal. If a cavity be made in a piece of charered as parallel. When parallel rays fall on a coal, and the substance to be aeted on be put in it, piece of glass having a double convex surface, that the effect produced by the lens will be much in

LEMUR. A genus of quadrupeds somewhat resembling the monkey in the form of the feet, but widely different from that animal in its manners and temper. Two of these animals brought from India lately, and exhibited in Boston, would walk backward and forward on a small tight cord, using their tails for balance poles.

creased. Any metal thus enclosed melts in a mo- | butter, and a few onions roasted in butter, are addment; the fire sparkling like that of a forge to ed, also salt; they are then boiled half an hour which the blast of a bellows is applied. more. A good soup may also be made of them. The image of an object when received through Some persons soften the lentils, before cooking, in a convex lens will be inverted. If you cause the cold water. Purified rain water is best to cook rays of light from the flame of a candle to pass them in. In the Archipelago, they are one of the through the glass of a common spectacle, and re-principal articles of food. To fatten pigs, lentils ceive them on a sheet of paper, or dark screen are excellent, and, given with other food, increase placed at a proper distance, you will see a com- the milk of cows. plete inverted image of the candle on it. A convex lens placed in the hole of a window shutter will exhibit, on a white sheet of paper situated in the focus of the glass, all the objects on the outside, as fields, trees, men, and houses, in an inverted order. The room should be quite dark, and the sun should shine upon the objects. A portable camera obscura may be made with a square box, in one side of which is to be fixed a tube, having a convex lens in it: within the box is a plane mirror, reclining backwards from the tube, in an angle of forty-five degrees. The picture is formed on a square of unpolished glass at the top of the box. If a piece of oiled paper be stretched on the glass, a landscape may be easily copied; or the outline may be sketched on the rough surface of the glass.

LEOPARD. An African animal of the cat kind, covered with black spots upon a yellow ground, so disposed, as to resemble the print of its foot. It is one of the most beautiful of all quadrupeds.

LEPROSY. The term leprosy is in familiar use, from the celebrated disease of that name occuring among the Jews, the various symptoms of which are so minutely detailed in Scripture, as well as the strict and severe regulations under which those were placed who were afflicted with it. This disease affects the skin, and sometimes increases in such a manner, as to produce scurf, scabs, and violent itchings, and to corrupt the whole mass of blood. At other times it is only a

LENT. A time of fasting and abstinence for deformity, and nothing more, as Hippdnetus inforty days before Easter.

LENTIL. A species of ervum. The common lentil comes from France and the Valais. The thin annual root brings forth weak, creeping, hairy, angular stalks, from one to two feet long, divided, from near the bottom, into several branches, and clinging for support to other plants; the primate leaves stand alternately; from the axils of the leaves proceed fine stalks, which each have two or three whitish flowers, hanging down. The pods do not contain more than two sound seeds, flat upon both sides. Lentils are cultivated for the seeds just mentioned. They require a rather sandy, yet strong soil; they are sown somewhat later than peas and retches, because they cannot endure night frosts; they are to be sowed in drills, and well harrowed. Care is to be taken that the seed is not put too deep into the ground, and that the young plants are well hoed and well weeded. For the harvest, the time is to be chosen when the little pods begin to turn brown, though the plant may be still quite green; and, if possible, it is best to choose the afternoon of a dry, warm day; for if the pods are quite ripe, or are wet with rain at the time of gathering, they easily crack open, and a great loss of seed takes place.

Two varieties are cultivated-the large garden lentil, and the common field lentil. The former is distinguished by its size, and the greater quantity of mealy substance which it will afford. The straw of lentils is good food for cattle and sheep, particularly for calves and lambs. Lentils are also mixed with vetches, and sowed as food, both green and dried, for milch kine. Lentils, when cooked, afford a nutritious food, (this should be done in the pod, to preserve their flavor) but, like peas and beans, are not good for persons whose digestive powers are weak, particularly if they are not cooked quite soft. They ought to be boiled for two hours and a half. When they are browned, some

forms us, where speaking of the lepers in the gospel cured by Jesus Christ. The Jews looked on a leprosy as a disease sent from God, and Moses prescribes no natural remedy for the cure of it. He requires no more, than that the diseased person should show himself to the priest, and that the priest should judge of his leprosy; if it appeared to be a real leprosy, capable of being communicated to others, he separated the leper from the company of mankind. He appoints certain sacrifices and particular ceremonies for the purification of a leper, and for restoring him to civil society, to the participation of things holy, and to the conversation of other men.

The marks which Moses gives for the better distinguishing a leprosy, are signs of the increase of this disease. An outward swelling, a pimple, a white spot, bright, and somewhat reddish, created just suspicions of a man's being attacked with it. When a bright spot something reddish or white appeared, and the hair of that place was of a pale red, and the place itself something deeper than the rest of the skin, this was a certain mark of a leprosy. They who have treated of this disease, have made the same remarks, but have distinguished a recent leprosy, from one already formed and become inveterate. A recent leprosy may be healed, but an inveterate one is incurable. Travellers who have seen lepers in the East say, that this disease attacks principally the feet. Maundrell, who had seen lepers in Palestine says, that their feet are swelled like those of elephants, or horses' feet, swelled with the farcy.

The common marks whereby physicians tell us an inveterate leprosy may be discerned, are these. It makes the voice hoarse, like that of a dog who had been barking a long time, and the voice comes through the nose rather than the mouth; the pulse is small and heavy, slow and disordered; the blood abounds with white and bright corpuscles, like millet seeds; it is all a scurfy serum, without due

begun, because that book, which treats of the fall of man, and the severe judgment of God inflicted on the world for sin, best suits with a time of repentance and mortification. After Genesis, follow chapters out of the books of the Old Testament, as they lie in order; only on festival Sundays, such as Easter, Whitsunday, &c., the particular history relating to that day is appointed to be read: and on the Saints' days, the church appoints lessons out of the moral books, such as Proverbs, Ecclesiastes, Ecclesiasticus, &c., as containing excellent instructions for the conduct of life.

mixture; so that the salt put into it does not melt. It is so dry that vinegar mixed with it bubbles up; it is so strongly knit together by imperceptible threads, that calcined lead thrown into it swims easily on the surface of it. The face is like a coal half extinguished, shining, unctuous, bloated, full of very hard pimples, with small kernels round about the bottom of them; the eyes are red and inflamed, and sparkle like those of a cat; they project out of the head, but cannot be moved either to the right or left. The ears are swelled and red, corroded with ulcers about the root of them, and encompassed with small kernels. The As to the second lessons, the church observes nose sinks, because the cartilage rots. The nos- the same course both on Sundays and week days; trils are open, and the passages stopped with ul-reading the gospel and Acts of the Apostles in the cers at the bottom. The tongue is dry, black, morning, and the epistles in the evening, in the swelled, ulcerated, shortened, divided in ridges, order they stand in the New Testament; excepting and beset with little white pimples. The skin of on Saints' days and holy days, when such lessons it is uneven, hard and insensible; even if a hole are appointed, as either explain the mystery, relate be made in it, or it is cut, instead of blood, putri- the history, or apply the example to us. fied liquor issues out of it.

The nature and causes of a leprosy have been much debated. The generality are of opinion, that the cause is internal, in the blood and humors; and that it does not appear outwardly till it has corrupted every thing within. Others are of the opinion, that it is owing to some outward cause.

In examining this matter it is necessary to distinguish two sorts of leprosies, one proceeding from inward corruption, the other received by outward communication. Corruption of the blood may be in different respects, the cause, and the effect of a leprosy. It is the cause of it, when the blood being inwardly corrupted, either by bad diet, or other causes, produces external effects. Corruption of the blood is the effect of this disease when it has been caught by touching any person infected with it, or any thing belonging to him; for a leprosy is very easily communicated; for which reason Moses has taken so much precaution to prevent lepers from any communication with persons in health. And his care extended even to dead bodies, thus infected, directing that they should not be buried with others.

LESSONS. Among Ecclesiastical Writers, portions of the holy scripture, read in Christian churches, at the time of divine service.

In the ancient church, reading the scriptures was one part of the service of the catechumens, at which all persons were allowed to be present, in order to obtain instruction.

The church of England, in the choice of lessons, proceeds as follows; for the first lesson or ordinary days, she directs, to begin at the beginning of the year with Genesis, and so continue on, till the books of the Old Testament are read over, only omitting the Chronicles, which are for the most part the same with the books of Samuel and Kings, and other particular chapters in other books, either because they contain names of persons, places, or other matters less profitable to ordinary readers.

The course of the first lessons for Sundays is regulated after a different manner. From Advent to Septuagesima Sunday some particular chapters of Isaiah are appointed to be read, because that book contains the clearest prophecies concerning Christ. Upon Septuagesima Sunday, Genesis is

LETHARGY. In Medicine, a disease wherein such a profound drowsiness or sleepiness attends the patient, that he can scarce be awaked, and if awaked, he remains stupid, without sense or memory, and presently sinks again into his former sleep.

LETTERS. The characters in the alphabet, expressing the sounds of words. There is no account of using letters before about the time of Moses; and probably one of the first books which was written was that of Job the Arabian, who is thought to have been contemporary with Moses. The first mention of a public or national record in writing, is in the seventeenth chapter of Exodus; when Joshua having defeated the armies of Amalek, the Lord said unto Moses, 'write this in a book for a memorial.' In the commonly received chronological table, it is stated that Memnon, the Egyptian, invented letters, one thousand eight hundred and twenty-two years before Christ's nativity, or two hundred and fifty-one years before the birth of Moses. It seems, however, uncertain, whether letters were invented by the Egyptians, Phoenicians, or Arabians. It is said that Sir Isaac Newton ascribed to the Midianites, the honor of instructing Moses in the art of writing, during his abode in Arabia, with Jethro his father-in-law. Moses is supposed to have written the book of Job, in the wilderness of Arabia, during the time that he kept Jethro's flock, at the foot of Mount Horeb.

LETTER OF ADVICE. A letter written by a merchant to his correspondent, advising or giving him notice of what bills he has drawn upon him.

LETTER OF ATTORNEY. In Law, is a letter by which one person authorises another to do some lawful act in his stead; as, to give seisin of lands, to receive debts, or to sue a third person.

The nature of this instrument is, to transfer to the person, to whom it is given, the whole power of the maker, to enable him to accomplish the act intended to be performed. It is either general, or special; and sometimes made revocable, which is, when a bare authority is only given; and sometimes it is irrevocable, as where debts, &c. are

assigned from one person to another. It is gen-earth. A true line of level is an arch of a great erally held, that the power granted to the attorney circle, which is imagined to be described upon a must be strictly pursued ; and that where it is made truly level surface. The apparent level is a to three persons, two cannot execute it. In most straight line, drawn tangent to an arch or line of cases, the power given by a letter of attorney de- true level. Every point of the apparent level, termines, or ceases, upon the death of the person except the point of contact, is higher than the who gave it. true level.