augmentation or increase of motion in accelerated bodies. The term is chiefly used in speaking of falling bodies, or the tendency of heavy bodies towards the centre of the earth produced by the power of gravity; which, acting constantly and uniformly upon them, they must necessarily acquire every instant a new increase of motion. ACCENT. Among grammarians, is the raising or lowering of the voice in pronouncing certain syllables of words. ACCEPTANCE. Among merchants, is the signing or subscribing a bill of exchange, by which the acceptor obliges himself to pay the contents of the bill. What constitutes an acceptance is, in many cases, a nice question of law; but the general mode is for the acceptor to write his name on some conspicuous part of the bill, accompanied by the word accepted. In France, Spain, and the other countries of Europe, where oral evidence in matters of contract is not admitted to the same extent as in England, a verbal acceptance of a bill of exchange is not valid. ACCESSORY. A person, in law, is said to be accessory to a crime, if he either commands or orders another to commit the crime, or furnishes the means for its commission. Those who receive, or comfort, any person guilty of murder, or felony, are also considered as accessory to the perpetration. In the lowest offences, such as riots and mobs, and in the highest, such as high treason, there are no accessories, all those concerned being regarded as principals. ACCLAMATION. A confused noise or shout, by which the public express their approbation or disapprobation of any thing said or done. Acclamations have been practised in theatres, senates, ecclesiastical meetings, elections, in triumphs, and at the celebration of nuptials. The Senate of Rome burst into contumelious acclamations after the death of Domitian and Commodus. The theatrical acclamations were connected with music. Nero, who was as fond of music as of blood, ordered 5000 soldiers to chant acclamations when he played in the theatre, and the spectators were obliged to join them. In the corrupt period of the Roman empire, the children and favorites of the emperors were received with loud acclamations, as the French emperor was greeted with Vive l'empereur! and the French king is with Vive le roi! The Turks have a custom somewhat similar, at the sight of their emperor and grand viziers. The form among the Jews was Hosanna! Before a system of voting is adopted, we find its place supplied, among all nations, by acclamations. So Tacitus informs us that the Germans showed their approbation of a measure by clashing their shields and swords. The Bishops, in the early times of Christianity, were long elected by acclamation. The first German emperors were elected by acclamation at a meeting of the people; and the Indians, in North America, show their approbation or disapprobation of proposed public measures by acclamations. ACCOMPANIMENT. In Music, a vocal or instrumental accessory, which may consist of an ACHROMATIC. Want of colors; applied to telescopes, contrived to remedy the aberrations of color. ACCUBATION. A posture of the body between sitting and lying. In this posture the Greeks and Romans reclined at table; a custom which they borrowed from the nations of the east. During the first ages of the republic, the Romans sat at meals; and Homer represents his heroes as sitting around the wall, on separate seats, with a small table before each, on which was set his portion of meat and drink. When the custom of reclining was first introduced at Rome, it was adopted only by the men; but afterwards, when the prevalence of luxury had overcome the sense of delicacy, women also were allowed to recline at table. It was only at supper that they were placed in this indulgent posture. They took their other meals without any formality, either alone or in company, sitting or standing. The Romans arranged themselves at supper in the following manner-In the cœnaculum, or dining room, three couches were placed around the table; three persons reclining on each couch. They reclined on the left arm, with the head a little raised, and the back supported by cushions. The feet of the first were stretched behind the back of the second, and the feet of the second behind the back of the third. Thus the head of the second was opposite to the breast of the first, separated only by a pillow; and when any of them wished to converse with another, placed higher on the same couch, he was obliged to lean on his bosom. The middle place was reckoned the most honorable; but when a consul happened to be present at an entertainment, he occupied the lowest place on the middle couch: because there he could most conveniently receive and answer messages. ACERRA. In antiquity a kind of altar erected by the Romans in honor of a person deceased; on which incense was daily burned till the time of his burial. A similar custom prevails among the Chinese. In a room hung round with mourning, they raise an altar, on which is placed an image of the deceased, and every one who approaches it, bows four times, and offers gifts and perfumes. ACID. In chemistry, a term originally synonymous with sour, and applied only to bodies distinguished by that state; but it now comprehends under it, all substances possessed of the following properties. Acids, when applied to the tongue, excite the sensation of sour; they change the blue colors of vegetables to red; they unite with water in almost any proportion; they combine with all the alkalies, and most of the metallic oxides and earths, | sumed that sound passes through 1142 feet of air in and form with them those compounds called in a second of time, and 13 miles in a minute. chemistry, salts. Every acid does not possess all these properties, but they all possess a sufficient number to distinguish them from other substances. ACRE. A measure of land very general in name, but differing almost in every two places as to extent, which it is intended to denote. A statute acre in England contains four square roods; a rood, containing forty perches or poles, of sixteen and a half feet each; but, in different countries, the length of the pole varies, from the statute measure of sixteen feet and a half, to twenty-eight. In Scotland, the acre is larger than in England. The French Strasburgh acre is about half an English acre. The Welsh acre commonly contains two English. The Irish acre is equal to one acre, two roods, 19.27 perches English. ACONITE, Wolfsbane, or Monkshood. A plant, the flower of which resembles the hood of a monk. There are several species of the aconite, most of which are violent poisons. The ancients were so surprised at their pernicious effects, that they were afraid to touch the plants; and hence sprung many superstitious precautions about the manner of gath-acre contains one English acre and a half. The ering them. Theophrastus relates that there was a mode of preparing the aconite in his days, so that it should only destroy at the end of one or two years. It is confidently affirmed, that the huntsmen on the Alps, who hunt the wolves, and other wild animals, dip their arrows in the juice of these plants, which renders the wounds occasioned by them mortal. A decoction of the roots has been used to kill bugs; and the powder disguised in bread, or some other palatable vehicle, has been employed to destroy rats and mice. Matthiolus relates that it was given by way of experiment to four condemned criminals, two at Rome in 1524, and two at Prague in 1561. Two of them died and the other two with great difficulty were recovered. ACORN. The seed or fruit of the oak; it was reckoned, in former times, an important article of human sustenance. We are told by historians, that the natives in the forests of Germany and Britain, fed on this fruit as a luxury; and that violent quarrels sometimes arose between the chiefs of their clans, respecting the division of their crops of acorns. According to Volney, the peasants of Syria, at this day, depend for a considerable part of their food on oakacorns, which they gather upon Mount Lebanon; for if they raise barley and wheat, the Arabs of the wilderness come in harvest time, and rob them of their crops. 121 ACROSTIC. A poem, of which the first, and sometimes the final letters of the lines or verses form some particular word or words. The middle letters, also, are sometimes used for the same purpose. The French abbés and nobles, before the revolution, often exercised their ingenuity in the composition of these poetical trifles. ACTION. In physics, is the pressure or percussion of one body against another. But when a body in motion strikes against another body, it meets with resistance from it; and the resistance of the body at rest will be equal to the blow struck by the body in motion; or to express the same in philosophical language, action and reaction will be equal and in opposite directions. It appears, therefore, that one body acting upon another, loses as much motion as it communicates, and that the sum of the motions of any two bodies in the same line of direction, cannot be changed by their mutual action. From the action and reaction of bodies we may learn in what manner a bird, by the stroke of its wings, is able to support its weight in the air. If the force with which it strikes the air below it, is equal to the weight of its body, then the reaction of the air upwards is likewise equal to it, and the bird being actwill rest between them. If the force of the stroke is greater than its weight, the bird will rise with the difference of these two forces; and if the stroke be less than its weight, then it will sink with the difference. In the act of rowing, the water is struck with the oars, in a direction opposite to that in which the boat is required to move; and the boat is driven along by the reaction of the water on the oars. ACOUSTICS. Is that science which instructs us in the nature of sound. It is analogous to op-ed upon by two equal forces in contrary directions, tics, and is divided into direct, refracted, and reflected sound; which may be improved in regard to the object, the medium, and the organ. The first in speaking, in whistling, singing, &c. which are all distinct arts and all improvable; secondly, by the position of the sonorous body. Sound may also be improved by the density of the medium, and by the sonorous body being placed near a smooth wall, either plain or arched; hence the theory of whispering places. Again by placing the sonorous body near water, its sound is mollified; by placing it on a plain it is conveyed to a greater distance than on uneven ground. As to the organ the ear, it is assisted by being placed near a wall, especially at one end of an arch, the sound beginning at the other; or near the surface of water or the earth; or by instruments, as the speaking trumpet; by a microphone, or magnifying ear instrument; or by a polyphone, or multiplying ear instrument. The usual medium of sound is air; in a receiver exhausted of air a bell can scarcely be heard at all. Sound is heard at a greater distance when carried with the wind or a current of air, than when passing in opposition to it. It is now generally as ACTORS AND ACTRESSES. Actresses, in the drama, appear to have been wholly unknown to the ancients, men and eunuchs always performing the female parts. Charles II. is said to have first encouraged their public appearance in England. Actors were long excluded from good society, and actresses still longer, and perhaps the English were the first who admitted the most distinguished into their first circles. At Athens, actors were highly honored. At Rome, they were despised, and deprived of the right of suffrage. The reason of this difference is, that, among the Greeks, the actors were freeborn citizens, and the dramatic performances had their origin in the sacred festivals; but, among the Romans, the drama was introduced by persons of the lowest class, Etruscan players and peasants of Atella. Actors and actresses continued for along time, to be treated with little regard in France, after they had been admitted into good society in England; and in some parts of Germany, they were formerly buried like suicides, in a corner of the burying ground, separated from the other graves. ACUPUNCTURE. A method of bleeding, in use among the Chinese and Japanese. It consists in driving a fine needle one or two inches into the flesh of the afflicted part; and it is applied to the most tender parts of the body. The opinions of the cause of relief by acupuncture are various. Some writers think a galvanic influence on the nerves takes place. ADAGIO. In music, signifies the second degree of music from slow to quick. It is applied to music not only meant to be performed in slow time, but also with grace and embellishment. ADDER. A snake of the viper kind. Its body is short and thick, and spotted with yellow. Its motion in running is slow; when provoked it throws itself into a coil, flattening the head, brandishing its forky tongue, and hissing as a goose. Like the rattle-snake it springs at a single leap towards the object of its vengeance, about the length of its body. The poison of its bite is mortal, unless a proper antidote be speedily administered. This venomous serpent was considerably common in some of the oldest settlements in New England, forty or fifty years ago; but the detested race has been gradually extirpated. ADHESION. The property of certain bodies to attract other bodies to themselves, or the force by which they adhere to each other. Adhesion denotes a union to a certain point between two distinct bodies; cohesion, the union of the parts of the same body so as to form one mass. Adhesion may take place between two solids, as two hemispheres of glass, or between a solid and a fluid, or between two fluids, as oil and water. Thus it is said that a fluid adheres to a solid, as water to the finger dipped into it. ADIPOCERE. Is a term formed of adeps, signifying fat, and cera, signifying wax, and denotes a substance, the nature and origin of which are thus explained. The changes which animal matter undergoes in its progress towards total decomposition, have been, for many obvious reasons, but little understood. But an opportunity for obtaining knowledge on the subject was offered at Paris in 1786 and 1787, when the old burial ground of the Innocens was laid out for building upon, in consequence of which, the surface, soil, and the animal remains contained therein, were removed. The cemetery having been for ages appropriated to the reception of the dead, in one of the most populous districts in Paris, was eminently well calculated to exhibit the various processes of animal decomposition; and, another favorable circumstance was, it contained several of those large pits, fosses communes, in which the bodies of the poor are deposited by hundreds. These pits are cavities thirty feet deep, with an area of twenty square feet, in which the shells containing the bodies are closely packed in rows over each other, without any intermediate earth, and with only a slight superficial covering of soil, not more than a foot thick. Each of these pits contained from 1200 to 1500 bodies, and may be considered as a mass of animal matter of the dimensions above mentioned. The first pit that was examined had been filled and closed up fifteen years before. On opening some of the coffins the bodies were found within shrunk, so as to leave a considerable vacant space in the upper part of the coffin, and flattened, as if they had been subject to a strong compression; the linen which covered them adhered firmly, and upon being removed, presented to view only irregular masses of soft, ductile, grayish-white matter, apparently intermediate between fat and wax. The bones were enveloped in this, and were found to be very brittle. The bodies thus changed, being but little offensive to the smell, a great number were dug up and minutely examined. In some the alteration had, as yet, only partially taken place, the remains of muscular fibres being still visible; but where the conversion had been complete, the bones throughout the whole body were found covered with this gray substance, generally soft and ductile, sometimes dry, but always readily separating into porous cavernous fragments, without the slightest trace of muscles, membranes, vessels, tendons, or nerves-the ligaments of the articulations had been in like manner changed; the connexion between the bones was destroyed, and these last had become so yielding, that the gravediggers, in order to remove the bodies more conveniently, rolled each upon itself from head to heels, without any difficulty. According to the testimony of these men, to whom the facts just mentioned had been long familiar, this conversion of animal mat ter is never observed in those bodies that are interred singly, but always takes place in the fosses communes. To effect this change nearly three years is required. Animal matter having once passed into this stage of decomposition, appears to resist for a long time any further alteration. Some of these pits that had been closed above forty years, were, upon examination, found to be little else than a solid mass of soapy matter; nor is it yet ascertained how long in common circumstances it would continue unchanged, the burial ground of the Innocens being so small in comparison to the population of the district, as to require each pit in thirty or forty years to be emptied of its contents, in order to receive a new accession of bodies. ADMIRAL. The commander-in-chief of a squadron or fleet of ships of war, or of the entire naval force of a country. Probably this word is of Arabic origin, and signifies originally the emir, or prince, of the waters. It is said, that the Sicilians were the first in Europe by whom the title of admiral was adopted; and, that they took it from the eastern nations, who visited them. It has also been asserted that the Genoese were the next who applied the word to the commander of a squadron. This appears to have been done in the time of the crusaders, and about the year 1244. ENIGMA, or ENIGMA. Is commonly called a riddle. The Greek words of which the term is formed, mean an obscure hint or saying. Enigmas may be either painted or written. In some foreign universities on the continent of Europe, monkish habits still retain so much influence, that the explanation of enigmas is a favorite scholastic exercise. The true end of language and of arts, however, is to enlighten, and not to obscure. Enigmas were the invention of intelligent men, who had the misfortune to live in countries, and in ages, where and when truth could not be spoken openly. In modern times, enigmas can serve no other purpose than that of enabling the inventor or propounder to obtain a contemptible triumph over those who do not happen to conjecture their meaning. An aptitude at unravelling them is, on the other hand, a talent scarcely to be desired. In all periods, enigma-makers seem to have endeavored rather to perplex and entrap than to inform. Hence the understanding of enigmas, or dark sentences, became proverbial among the Hebrews, intimating skill in discovering mysteries, and deciphering intricate combinations of letters or sentences. of the philosophical world. Observing the natura ascent of smoke and clouds in the atmosphere, those artists were led to suppose that heated air, if enclosed in a suitable covering, would also prove buoyant. After several smaller experiments, by which this idea was fully confirmed, they inflated a large balloon with rarefied air, which immediately and rapidly rose to the height of six thousand feet, and answered their most sanguine expectations. It was soon found that machines of this kind might be so contrived, as to convey small animals, and even human beings, through the air with ease. The first adventurer in this aerial navigation was Pilatre de Rozier, a daring Frenchman, who rose in a large balloon from a garden in the city of Paris, on the 15th of October, 1783, and remained a considerable time suspended in the air. He made several aerial voyages afterwards of greater extent, and in two of them was attended by other persons. In a short time, however, the use of rarefied air, in aërostation was for the most part laid aside, as inconvenient and unsafe. On recurring once more to the discovery of Mr. Cavendish, the philosophers of Paris concluded that a balloon, inflated with hydrogen gas, would answer all the purposes of that contrived by the Montgolfiers, and would also possess several additional advantages. They made their first experiment in August, 1783, which was attended with complete success. Since that time, air-balloons filled with rarefied air have not been generally used. AEROSTATION. In the modern application of the term, signifies the art of navigating through the air, both in its principles and practice. Hence also the machines which are employed for this purpose, are called aërostats, or aerostatic machines; and on account of their round figure, air-balloons. Air-balloons are of two kinds, those filled with rarefied air, and those filled with hydrogen gas. The best forms for balloons are globular or oval. Large balloons, for hydrogen gas, must be made of The first aerial voyage in England was performsilk, and varnished over so as to be air-tight. The ed by Vincent Lunardi, a native of Italy. The car, or boat, is made of wicker-work, covered with diameter of his balloon was thirty-three feet. Soon leather, well varnished or painted, and is suspended after, Mr. Blanchard ascended, carrying up a pigeon, by ropes proceeding from the net which goes over which flew away from the boat, labored for somethe balloon. The hydrogen gas for filling the bal-time with its wings to sustain itself in the air, and loon is procured by putting a quantity of iron-filings, finally returned and rested on one side of the boat. or turnings, with some sulphuric acid diluted with He ascended so high as to experience great difficulwater, into casks lined with lead. From the top ty of breathing, but perceiving the sea before him, of these casks tin tubes proceed, which unite into he descended near Ramsey, about seventy-five one that is connected with the silk tube of the bal- miles from London, having travelled at the rate of loon. Balloons of oiled silk cannot be made small- nearly twenty miles an hour. er than five or six feet in diameter, as the weight of the material is too great for the air to buoy it up. In 1729, Bartholomew Gusman, a Jesuit of Lisbon, caused an aerostatic machine, in the form of a bird, to be constructed, and made it ascend, by means of a fire kindled under it, in the presence of the king, queen, and a great concourse of spectators. Unfortunately, in rising, it struck against a cornice, was torn, and fell to the ground. The inventor proposed renewing his experiment; but the people had denounced him to the inquisition as a sorcerer, and he withdrew into Spain, where he died in an hospital. In 1766, the Honorable Henry Cavendish discovered that hydrogen gas (then called inflammable air,) was at least seven times lighter than common air. It occurred soon afterwards to the celebrated Dr. Black, that if a thin bag were filled with this gaseous substance, it would, according to the established laws of specific gravity, rise in the common atmosphere; but he did not pursue the inquiry. The same idea was conceived by Mr. Cavallo, to whom is generally ascribed the honor of commencing the experiments on this subject. He had made but little progress, however, in these experiments, when the discovery of Stephen and John Montgolfier, paper manufacturers of France, was announced in 1782, and engaged the attention The singular experiment of ascending into the atmosphere with a balloon, and of descending with a machine, called a parachute, in the form of a large umbrella, was performed by Mr. Garnerin in 1802. The weather was clear and pleasant, and the wind was gentle. In about eight minutes the balloon and parachute had ascended to an immense height, and Mr. Garnerin in the basket, could scarcely be perceived. While the spectators were contemplating the grand sight before them, Mr. Garnerin cut the rope, and in an instant he was separated from the balloon, trusting his safety to the parachute. Before the parachute opened, he fell with great velocity; but as soon as the parachute was expanded, which took place a few moments after, the descent became very gentle and gradual. It was observed that the parachute, with the appendage of cords and basket soon began to vibrate like the pendulum of a clock, and the vibrations were so great, that more than once the parachute, and the basket with Mr. Garnerin, seemed to be on the same level, or quite horizontal; the extent of the vibrations, however, diminished as he descended. On coming to the earth, he experienced some strong shocks, but soon recovered, and remained without any material injury. The fate of Rozier, the first aerial navigator, and of his companion Romain, has been much lamented. They ascended with an intention of crossing the channel to England. Their machine consisted of a spherical balloon, filled with hydrogen gas, and under this balloon, a smaller one filled with rarefied air, designed to diminish the specific gravity of the whole apparatus. For the first twenty minutes they seemed to pursue the proper course; but the balloon appeared to be much inflated, and the aeronauts appeared anxious to descend. Soon, however, when they were at the height of three-quarters of a mile, the whole apparatus was in flames, and the unfortunate adventurers fell to the ground, and were killed. The invention of balloons cannot be considered as having added much to the comfort or utility of man. The only practical purposes which it has been made to subserve, are those of aiding meteorological inquiries, and of inspecting the fortifications and reconnoitring the camp of an enemy, which could not be approached by other means. The difficulties, under which this species of navigation labors, appear at present to be insurmountable; and the want of some means to control and regulate the movements of the aerial vessel is so essential, as to excite a fear that it cannot be supplied. AFFINITY. In law, is that degree of connexion, which subsists between one of two married persons and the blood relations of the other. It is no real kindred. A person cannot, by legal succession, receive an inheritance from a relation by affinity; neither does it extend to the nearest relations of husband and wife, so as to create a mutual relation between them. The degrees of affinity are computed in the same way as those of consanguinity, or blood. By the Jewish law, marriage was prohibited within certain degrees. Nearly the same limitations are adopted in the laws of Europe and America. All legal impediments, arising from affinity, cease upon the death of the husband or wife, excepting, of course, those which relate to the mar riage of the survivor. The table of forbidden degrees of affinity, by the ecclesiastical law of England, is commanded to be hung up in all churches. AFFIRMATION. Signifies, in one sense, the solemn declarations of Quakers, and of members of some other sects, in confirmation of their testimony in courts of law, or of their statements on other occasions, on which the sanction of an oath is required of other persons. The English laws did not permit affirmations instead of oaths, in criminal cases, until 1828. No distinction has been made in the United States, between testimonies in civil and criminal cases in this respect, it having been permitted to Quakers generally, and, for the most part, to other persons scrupulous about swearing, to give testimony upon mere solemn affirmation. Even the President of the United States is allowed to affirm instead of taking the usual oath, when inducted into office, if he has conscientious scruples about swearing. The privilege of affirmation is allowed in Prussia only to sects recognised by government, and whose principles do not permit them to make oath. False affirmation is subjected to the same penalties as perjury in England and elsewhere. AGA. Among the Turks, the commander of a body of infantry; likewise a title of politeness. The aga of the Janizaries, their commander in chief, had nearly as much authority as the grand vizier, and was the only person allowed to appear before the grand signior, without his arms crossed on his breast, in the attitude of a slave. The word Aga is often used, as a complimentary title in Turkey, much in the same way as captain in some parts of the United States. AGAPE. The feasts of friendship, charity, or kindness, in use among the primitive Christians, were called by this name. The following account is given of their origin. The first Christians had all things in common, as we read in the Acts of the Apostles; but when that equality of possession ceased, as it did even in the time of the apostles, the agape or love-feast was substituted in the room of it. Upon certain days after partaking of the Lord's Supper, they met at a common feast, the rich bringing provisions, and the poor who had nothing, being invited. The Jews had certain devotional entertainments, in some degree related to the agape. On their great festival days they made feasts for their family, the priests, the poor, and orphans; or they sent portions to them. These repasts were made in Jerusalem. Also, there were certain sacrifices and first fruits appointed by the law, to be set apart for this purpose. The love-feasts of the Christians, during the three first centuries, were held in the churches without scandal, but, in after-times, they became occasions of wickedness. The heathen charged them with impurity. This led to a reformation. The kiss of charity, with which the ceremony used to end was no longer given between different sexes, and it was expressly forbidden to have any beds or couches for the convenience of those who wished to eat at their ease. AGATE. A precious stone, which naturalists have ranked among the demi-transparent precious stones. It is supposed that the name agate comes from that of the river Achates, in the valley of Noto, in Sicily, which is at present called Drillo; it being said, that the first agates that were noticed were found upon the shores of that river. Agates are distinguished with reference to their degrees of transparency, into two kinds, and called oriental and occidental: the first generally comes from the eastern parts of the world, as its name implies; and the second is found in the western, as Germany, Bohemia, and other countries. The oriental agate is known by its clearness, transparency, and the beautiful polish of which it is susceptible: the occidental, on the other hand, is obscure, its transparency cloudy, and its polish much inferior to that of the former. All agates from the east have not, however, the perfections for which this class are celebrated; and some occidental are occasionally found, that may be compared to the oriental without disadvantage. It is more difficult to distinguish the agate from other demi-transparent stones, such as the chalcedonix, the sardonix, than to recognise it among stones entirely opaque. Owing to this variety, and this affinity to other stones, which are its characteristics, the agate has been divided into several kinds. The agate, simply so called, is of one color or |