538,29

HARVARD

COLLEGE LIBRARY

49-56

L,

or 1, the eleventh letter of our alphabet; a numeral denoting 50; and with a dash over it, 50,000. LA, in Music, the syllable by which Guido denotes the last sound of each hexachord; if it begins in C, it answers to our A, if in G to E; and if in F to D.

LABDANUM, or LADANUM, is a resin obtained from the surface of the cystus Creticus, a shrub which grows in Syria, and the Grecian islands. It is collected while moist, by drawing over it a kind of rake, with thongs fixed to it, from which it is afterwards scraped. When it is very good, it is black, soft, and has a fragrant odour and a bitterish taste. Water dissolves about a twelfth part of it, and the matter taken up possesses gummy properties. When distilled with water, a small quantity of volatile oil arises. Alcohol may also be impregnated with the taste and odour of labdanum.

LABEL, in Navigation, a thin brass ruler used in taking ahitudes. In Law, a slip of paper or parchment that holds the seal. In Pharmacy, directions for the use of medicine. LABIAL LETTERS, those pronounced chiefly by means of the lips.

LABORATORY, in Military affairs, signifies that place where all sorts of fireworks are prepared, both for actual service and for experiments, viz. quick matches, fuzes, port-fire, grape shot, case shot, carcasses and grenades, cartridges, shells filled, and fuzes fixed, wads, &c. &c.

LABORATORY, in Chemistry, the room in which the artist keeps his utensils, and makes his experiments.

LABOURING, implies pitching or rolling heavily in a tur balent sea, an effect by which the masts and hull of the ship are greatly endangered; because, by the rolling motion, the masts strain upon their shrouds with an effort which increases as the sine of their obliquity; and the continual agitation of the vessel often loosens her joints, and makes her extremely leaky.

LABYRINTH, among the ancients, was a large intricate edifice cat into various aisles and meanders, running into each other, so as to render it difficult to get out of it. There is mention made of several of those edifices among the ancients; but the most celebrated are the Egyptian and Cretan labyrinths. LAC is a resinous substance, the production of an hemipterous insect, which is found on three or four different kinds of trees in the East Indies. The head and trunk of the lac insect seem to form one uniform, oval, and compressed red body, about the size of a flea. The antennæ are thread-shaped, and half the length of the body. The tail is a little white point, from whence proceed two horizontal hairs as long as the body. These insects pierce the small branches of the trees on which they feed; and the juice that exudes from the wounds is formed by them into a kind of cells, or nidus for their eggs. Lac is imported into this country adhering to the branches in small transparent grains, or in semi-transparent flat cakes. Of these the first is called stick lac, the second seed lac, and the third shell lac. On breaking a piece of stick lac, it appears to be composed of regular honeycomb-like cells, with small red bodies lodged in them; these are the young insects, and to them the lac owes its tincture, for when freed from them its colour is very faint. Seed lae is the same substance grossly pounded, and deprived of its colouring matter, which is used by dyers and for other purposes; and shell lac is the cells liquefied, strained, and formed into thin cakes.

LAC Sulphuris, in Medicine, a sulphur, separated by acid from its alkaline solution, which renders it milder. SULPHUR.

See

LACCIC ACID, in Chemistry, a white or yellowish production of insects, called white lac. Some of this substance, brought from Madras, was analyzed, and found to bear a considerable analogy to bees' wax. The component parts of this acid are carbon, hydrogen, and oxygen.

LACE, in Commerce, a work composed of many threads of gold, silver, or silk, interwoven one with the other, and worked upon a pillow with spindles, according to the pattern designed;

the open work being formed with pins, which are placed and displaced as the spindles are moved. For cleaning gold lace and embroidery when tarnished, alkaline liquors are not to be used, for they corrode the silk, and change or discharge its colour. Soap also alters the shade of certain colours. But spirit of wine may be used without any danger of its injuring either the colour or quality, and in many cases proves as effectual for restoring the lustre of the gold, as the corrosive detergents.

LACE Bone, a lace made of fine linen, thread, or silk, much in the same manner as that of gold and silver. The pattern of the lace is fixed upon a large round pillow, and pins being stuck into the holes or openings in the pattern, the threads are interwoven by means of a number of bobbins made of bone or ivory, each of which contains a small quantity of fine thread, in such a manner as to make the lace exactly resemble the pattern.

LACERTA, the Lizard, was added by Hevelius to the old constellations. Boundaries and Contents: north by Cepheus, west by Cygnus, south by Pegasus, and east by Andromeda. In general it lies between Cygnus and Andromeda, and contains sixteen stars, three of the fourth magnitude, the remainder being smaller.

LACHRYMATORY, in antiquity, a vessel wherein were collected the tears of a deceased person's friends, and preserved along with the ashes and urn. They were small glass or earthen bottles, chiefly in the form of phials. At the Roman funerals, the friends of the deceased, or the præficæ, women hired for that purpose, used to fill them with their tears. and deposit them very carefully with the ashes, in testimony of their sorrow, imagining the manes of the deceased were thereby greatly comforted. Many specimens of them are preserved in the cabinets of the curious, particularly in the British Museum. LACK OF RUPEES, is 100,000 rupees; which, at 2s. 6d. each, amounts to £12,500 sterling.

LACTATES, combinations of earths and alkalies, &c. with the lactic acid.

LACTATION, among medical writers, denotes the giving suck. The mother's breast, if possible, should be allowed the child, at least during the first month; for the child is thus peculiarly benefited by what it sucks, and the mother is preserved from more real inconveniences than the falsely delicate imagine they would suffer by compliance herewith; but if, by reason of an infirm constitution, or other causes, the mother cannot suckle her child, let dry-nursing, under the mother's eye, be pursued.-When women lose their appetite by giving suck, both the children and themselves are thereby injured: wet nurses are to be preferred, who, during the time they give the breast, have rather an increased appetite, and digest more quickly; the former are apt to waste away, and sometimes die consumptive. In short, those nurses with whom lactation may for a while agree, should wean the child as soon as their appetite lessens, their strength seems to fail, or a tendency to hysteric symptoms is manifest.

When the new-born child is to be brought up by the mother's breast, apply it thereto in ten or twelve hours after delivery; thus the milk is sooner and more easily supplied, and there is less hazard of a fever than when the child is not put to it before the milk begins to flow of itself. If the mother does not suckle her child, her breasts should be kept so warm with flannel, or with a bare-skin, that a constant perspiration may be supported; thus there rarely will arise much inconvenience from the milk. The child, notwithstanding all our care in dry nursing, sometimes pines if a breast is not allowed. In this case a wet nurse should be provided; if possible, one that has not been long delivered of a child. She should be young, of a healthy habit, and an active disposition, a mild temper, and with breasts well filled with milk. If the milk is good, it is sweetish to the taste, and totally free from saltness; to the eye it appears thin, and of a bluish cast.

LACTIC ACID. By evapor evaporating sour whey to one one-eighth, filtering, precipitating with lime-water, and separating the lime by oxalic acid, Scheele obtained an aqueous solution of what he supposed to be a peculiar acid, and called it lactic acid.

Bouillou Lagrange as need it more narrowly, and

concluded it to

B

acetic acid, muriate of potash, a' small partion of iron, and animal matter, 25719-do namrob LACTIFEROUS, an appellation given to plants abounding with a milky juice, as the sowthistle and the like. The name of lactiferous, or lactescent, is given to all those plants which abound a thick coloured juice, without regarding whether it is white or not. Most lactiferous plants are poisonons, except those with compound flowers, which are generally of an innocent quality. Of the poisonous lactescent plants the most remarkable are suntach, agaric, maple, burning thorny plant, cassada, celandine, spurge," prickly poppy; and the plants of the natural unde Contorta, as swallow-wort, apocynum, cynanchum, and cerbera. The bell-shaped flowers are partly noxious, as cardinal flower; partly innocent, as campanula. Among the lactescent plants with compound flowers, that are innocent in their quality, may be mentioned dandelion, pieris, hyoseris, wild lettuce, gum succory; hawkweed, bastard hawk weed, hypochoeris, goat's-beard, and most species of lettuce; we say most species, because the prickly species of that genus are said to be of a very virulent and poisonous nature; though Mr. Lightfoot denies this, and affirms, that they are safe and gentle opiates, and that a syrup made from the leaves and stalks is much preferable to the common diacodium.

LACTOMETER, the name of an instrument used for the purpose of ascertaining the different qualities of milk, from its specific gravity compared with water, and its degrees of temperature under various circumstances. It was invented by M. Dicas, mathematical instrument maker, of Liverpool, but is yet in its infancy,?fe of „dergol, d zincią to zu126 ZITT

G

LAOTUCA, Lettuce, a genus of the syngenesia polygamia æqualis class and order of plants. Natural order of compo sitæ semiflosculosa. Ciclioraceæ Jussieu. There are eleven species; of L. sativa, or common garden lettuce, there are fifteen varieties.

LACUNAR, in Architecture, an arched roof or ceiling, more especially the planking or flooring above porticos or piazzas. *: LADDER, 'a well-known convenience, of which there are a great number. In a ship, ladders serve as stairs whereby to ascend or descend from one deck to another; and are distinguished by epithets, according to the several hatchways or other parts of a ship wherein they are situated.

Scaling LADDERS, in the Military art, are used in scaling when a place is to be taken by surprise. They are made several ways: in England, they are made of flat staves, so that they may move about their pins, and shut like a parallel raler, for conveniently carrying them the French make them of several pieces, so as to be joined together, and to be made of any necessary length; sometimes they are made of single ropes, knotted at proper distances, with iron hooks at each end, one to fasten them up the wall above, and the other in the ground; and sometimes they are made with two ropes, and staves between them, to keep the ropes at a proper distance, and to tread upon. When they are used in the action of scaling walls, they ought to be rather too long than too short, and to be given in charge only to the stoutest of the detachment. erw bu agomel 112 1 bogreol 16q Thompson's Mechanical LADDER.This ladder is a very ingenious contrivance, invented by a gentleman of the name of Thompson, and called by him the mechanical ladder. A A in the accompanying sketch, denote parallel ropes stretched and placed for the purpose of steadily conducting a seat or carriage C, in which a man may sit, and descend from the upper to the lower points of A A; these lines may be placed either in a perpendicular or inclined position; but an inclined position, forming an angle of about twenty degrees with the perpendicular, will in general be found most eligible. The carriage C may be connected by ropes, by rings, loops, or any kind of bearing parts which will confine it to a regular ascent and descent. It is connected with the counterpoise or place of reaction, E, by a rope passing over the pulley D. B B represents a ladder for the workmen to ascend. 6T vand]

ancom id botix mod The manner of working this machine 11951 21eband goal is as follows: the workman ascends by drgasite sin

B

B B, and places himself in the carri age C.in which his weight (by preference) forms nearly an equilibrium with buthe weight E, which may, for example, 90be imagined a basket of coals. Either by taking hold of the leading ropes, or eich unsofa rope passing downwards for that purpose, he causes the carriage to deobinte todas foot scend briskly, which at the same time abrones with debrings up E. He then quits the carri i sage, and at that time, E (which we may to 29 suppose to have been emptied by anoxit ebano sonother assistant by reversing it (or othermise) being somewhat heavier than C, -110 Af descends again, and raises C. to its first -b mi abitube 08116 5(situation, and by the time E is again 1970 Jonns filled, the workman is ready at the top 101 1wnem go to of the ladder, where he enters the carlines briage, and raises a second load; and Sanotto in this way the work may be continued at pleasure. It is evident that this work may be performed by two or more Pol Workmen ascending and descending in succession by means of the same ladbirder; or, if more convenient, by more ladders than one, and in case it should be desired to lift the body E through a greater space than is to be aséended by the workmen, upon B B, the purpose may be effected by fixing D higher, and causing two carriages to descend in succession along the ropes A A, though this plan is not particularly to be recommended.

The rope D E may also be wound on a barrel, and the rope DC on another, or similar barrel, both on the same axis. The parts of the machine A A, may instead of ropes be wooden or metallic sliders.d; to eq #cná DZUAN

This machinery, the inventor observes, is applicable to draw. ing, driving, forcing, impressing, or moving bodies of every description, and that in such applications of it, no other variations in the construction, connexion, or method of working it, will be needful, than such as any person possessing an ordinary acquaintance with mechanical operations, may execute with facility by tethe

The vulgar objection to the plan is ascending the ladder, yet this is its chief recommendation, for it is the easiest method of raising a weight. The truth of this assertion will be ascertained from the following statement.

If it be required to raise a sack of corn, a basket of coals, or any other equal weight, to the height of forty feet, (more or less) no method can be so easy to the person who is to raise the weight, as to ascend stairs or a ladder unencumbered, and to raise the sack, &c. by his own weight. By no other exertion of his own, nor by the assistance of any mechanical powers, can be perform the same operation in the same time. It must consequently be the easiest mode of raising a weight,, or it could not be done in the shortest time. If it is easier in one operation, it must be equally so in any number of operations. If it is easier for one man, it must be equally so where any number of men can be employed to work together in raising heavy weights, and where this principle can be introduced. If it is easier, it must be cheaper. The labour consists in ascending the ladder, and in this exertion the man's muscular powers are all in action at the same time; not partially used, as in most other modes of raising weights. His strength may be combined with his gravity in his descent, and if opposed by the least possible friction, he cannot work with greater advantage.

Desaguliers states the maximum of a man's power as under: One man 500 pounds, 12 feet, 1 minute. The weight raised was water in a bucket. The man, who was very powerful, ascended stairs with a weight about his own person, which, together with his own, was equal to the water, and placed himself on or in an empty bucket, which was suspended by a rope passing over a pulley, and fastened to the bucket containing the water below, and raised it in the time. The man was so exhausted, that he could not repeat the operation.

The following experiment has often been exhibited by means of the present invention. One man, 1500 pounds, 12 feet, 1 minate. And this difference arises from the man's strength being combined with his gravity, and the facilities which the two parallel ropes afford bim, to gain velocity by a slight exertion of his arms to arrest his descent, and quickly to re-ascend the ladder. If a man weighs 14 stone, or 190 pounds, and ascends the ladder eight, Limes in a minute (which almost any active man way do) it is clear that he can raise eight times his ownow eight, or 1568 pounds. 780121

The steps of the ladder being one foot apart that stride being found most agreeable to the inbpurers) if a man ascends as slowly as possible, that, is, the rate of one foot in each second, he will ascend five times in a minute to the height of twelve feet; and if he weigles twelve stone, or 168 pounds (the average weight of a labouring man) he will raise his weight five times, or 840 pounds in that time. He will probably consume ten seconds in ascending, and one or two seconds in descending and raising the aveight. He cannot work slower. Applying this rates of work, the result of one man's power for bne hour in raising the under-mentioned articles will be,

De Coals, !!!..NI ANDA JIE CEM.

Malt, Barley, Oats, &c.
Brick's, Sumantry ul. 2 !!
Water,

**་ ་ ཾ.*

10 chaldrons 20 feet.

190 quarters 20 feet. 2,6000 quarters 20 feet. 43000 gallons 20 feet,

There are four men employed to raise a basket of chals on the river Thames, and six on many parts of the roast. It has hitherto (in 1810) been found impossible to establish, or even try this plan on board of any collier in the river Thames; but it has been used at Brighton, where one of Lathmar's ships was discharged by it, with four men short of the usual complement, and in rather less than the usual time; only four men being employed to work in the hold, they could not fill the basket faster, or the vessel would have been discharged in half the usual time. The two men who worked the machine, waited nearly half of the time for a supply, and could have raised 20 Chaldrons per hour instead of 12, the quantity with which they were supplied.

This plan has for a considérable time been established at the East India Docks, where all the Indiamen are discharged by it. The first ship on board of which it was tried, was the Fort William, laden with bales of cotton, weighing about two hundred and three-quarters each. The bates were raised by two men only. The Porcher was delivered at the same time by the old plan, and contained a similar cargo; each bale was raised by six-men. From the Fort William 5632 bales were delivered in 17 days from the Porcher, 5022 in 20 days; leaving an advantage of four men, three days, and a surplus of 510 bales in favour of the Fort William The men who raised the bales on board the Fort William stood still nearly half the time, as the weigher could not pass the bales quicker through the Beates. The men who raised the bales from the Porcher were fully employed, and exerted themselves to the utmost, with the hope of preventing the establishment of the new plan.rta The inventor of this machine took out a patent for it, the specification of which is dated March 20, 1809. He offered the use of his invention to the City of London, without the reservation of any remuneration to himself, stipulating only that a part of the saving arising from it might be devoted to a fond for bettering the present and future condition of the men, to whose labours it was chiefly applicable; so as eventually to establish some asylum or provision for them and their families, when age or accident might have disabled them from working.

The male in baskets similar to those used on the river Thames.

The advantages derivable from the machine, were confirmed before Sir Charles Flower, the Lord Mayor in 1809, by the affidavits of two men who used it; by which it appeared that they had actually been able to perform with it more work than had ever been done by any four men in the same time. The inventor, in his memorial to the Lord Mayor and Court of Aldermen, observes, "that any man may work by his plan, no drilling being required; and as it is merely an improvement of the old principle, it should not be regarded as the substitution of any other power for that of man, as steam, horsepower, &c." tar

The foregoing statements we have extracted from a very useful work in two volumes, called "The Mechanic, or Compendium of Practical, Inventions," in which a description of a great number of very useful inventions may be found.

LADEN, the state of a ship when she is charged with a weight or quantity of materials equal to her tonnage or burden. If the goods, with which she is laden, be extremely heavy, her burden is determined by the weight thereof; but if light, she carries as much as she can stow, for the purposes of navigation. As a ton measure is generally estimated at 2000lbs in weight, a vessel of 200 tons ought accordingly to carry a weight equal to 400,000 pounds; therefore, when the matter of which the cargo is composed is specifically heavier than the water in which she floats, or, in other words, when the cargo is so heavy that she cannot float high enough, with so great a quantity of it as her hold will contain, a diminution thereof becomes absolutely necessary..makoouth pragya da

LADY. This title is derived from two Saxon words, which words bave in time been contracted into the present appellation. It properly belongs only to the daughters of earls, and all of higher rank; but custom has made it a word of complaisance for the wives of knights, and of all eminent women, LÆTIA, a genus of plants belonging to the polyandria class, and in the natural, method, ranking with those of which the order is doubtful. var

LAGURUS, a genus of plants belonging to the triandria class, and in the natural method ranking under the fourth order, gramina.

LAITY, the people, as distinguished from the clergy; see CLERGY The lay part of his majesty's subjects is divided into three distinct states; the civil, the military, and the maritime. See CIVIL, MILITARY, and MARITIME.

LAKE, a collection of waters which usually receives and discharges rivers. Of lakes, which both receive and emit rivers, we reckon three kinds, as the quantity they emit is greater, equal, or less than they receive. If it be greater, it is plain that they must be supplied by springs at the bottom; if less, the surplus of the water is probably spent in exhalation; and if it be equal, their springs just supply what is evaporated by the sun. Lakes are also divided into those of fresh water, and those of salt. Large lakes answer the most valuable purposes in the northern regions,

LALANDE, JOSEPH JEROME LE FRANCAIS, a celebrated French astronomer, was born at Bourg, in the department of L'Ain, in July, 1732. He was first intended for the bar, but his genius having been very early directed to astronomical subjects, his first intention was given up; and he followed his astronomical pursuits under the celebrated Lemonier, with the greatest success. Lalande was also an associate of the principal learned societies in Europe, and was for many years the centre of communication amongst the most celebrated of their members. After a long and useful life in the pursuit of science, he died on the fourth of April, 1807, being then in the 75th year of his age,

LAMA, the sovereign pontiff, or rather god, of the Asiatic Tartars, and hea

LAMB, THE BAROMETZ, or TARTARIAN.-Whoever has perused the accounts of early travellers, must recollect the stories that have been copied into our ancient berbals, of Tartarian sheep growing upon stems in the earth, and thence devouring all the vegetables that came within their reach.

A tale of this kind could not fail to attract the attention of the immortal father of modern botany, who took considerable pains to investigate it, and ascertained that, in the eastern part