waterings must not be frequent nor plentiful, and during winter, very sparing. The pots must constantly remain plunged in the tan-bed; for if they are taken out and placed on shelves in the stove, their fibres often shrink, and thus their roots decay. By this management these plants have greatly multiplied, and the common ginger has produced roots, weighing five or six ounces; but the others have been nearly a pound weight. In the West Indies the ginger thrives best in a rich cool soil; in a more clayey soil the root shrinks less in scalding. The land laid out for the cul ure of it is first well cleared and hoed, and then slightly trenched, and planted in March or April; it flowers about September; and when the stalks are wholly withered, the roots are fit to be taken up, which is generally done in January and February.

AMONTONS (WILLIAM), in biography, an ingenious French experimental philosopher, was born in Normandy the 31st of August 1663. While at the grammar school, he by sickness contracted a deafness that almost excluded him from the conversation of mankind. In this situation he applied himself to the study of geometry and mechanics; with which he was so delighted, that it is said he refused to try any remedy for his disorder, either because he deemed it incurable, or because it increased his attention to his studies. Among other objects of his study, were the arts of drawing, of land-surveying, and of building; and shortly after he acquired some knowledge of those more sublime laws, by which the universe is regulated. He studied with great care the natue of barometers and thermometers; and wrote his treatise of "Observations and Experiments concerning a new Hourglass, and concerning Barometers, Thermometers, and Hygroscopes;" as also some pieces in the Journal des Savans. In 1687, he presented a new hygroscope to the Academy of Sciences, which was much ap. proved. He found out a method of conveying intelligence to a great distance in a short space of time: this was by making signals from one person to another, placed at as great distances from each other, as they could see the signals by means of telescopes: this was unquestionably done upon the principal of modern telegraphs, which were brought into general use in 1794, almost a century after the death of Amontons. Amontons was chosen a member of the Royal Academy in 1699, as an eleve under the third astronomer; and he read there

his "New Theory of Friction," in which he happily cleared up an important object in mechanics. He had a particular genius for making experiments: his notions were just and delicate: he knew how to prevent the inconveniences of his new inventions, and had a wonderful skill in executing them. He died of an inflammation in his bowels, the 11th of October 1705, being only 42 years of age. His pieces are contained in tlie different volumes of the memoirs of the Academy of Sciences; these are numerous, and upon various subjects, as the air, action of fire, barometers, thermometers, hygrometers, friction, machines, heat, cold, rarefactions, pumps, &c. They may be seen in the volumes for the years 1696, 1699, 1702, 1703, 1704, and 1705. The character of Amontons for integrity, modesty, and can dour, was no less distinguished than his talents and genius in philosophical pursuits Upon his death in 1705, M. Fontenelle delivered an elegant and impressive eulogium on his merits. See MEMOIRS of the Academy for that year.

AMORPHA, in botany, bastard indigo, a genus of plants, belonging to the Diadelphia Decandria class of Linnæus; the flower of which consists of one petal vertically ovated, hollow, and erect; and the fruit is a lunulated pod, of a compressed form, and covered with tubercles, in which are contained two seeds, of an oblong kidney-like shape. There are two species.

This shrub grows naturally in Carolina, where formerly the inhabitants made a coarse sort of indigo, which occasioned its name of the bastard indigo. It rises with many irregular stems to the height of twelve or fourteen feet, with very long-winged leaves. It was observed by Thunberg in the island of Niphon, belonging to Japan, but is now become very common in the gardens and nurseries near London, where it is propagated as a flowering shrub. It is propagated by seeds sent from America.

AMPELIS, in natural history, the chatterer, a genus of birds of the order Passeres: bill straight, convex, subincurved, each mandible notched: nostrils covered with bristles: tongue sharp, cartilagenous, bifid: middle toe connected at the base to the outside. There are, according to Gmelin, fourteen species: we shall notice the following: A. garrulus, or waxen chatterer; a beantiful bird about eight inches long. Its bill is black, and has a small notch at the end ; its eyes are placed in a band of black, which passes from the base of the bill to the hinder

part of the head. Its throat is black; its feather on the head are long, forming a crest; all the upper parts of the body are of a reddish ash colour; the breast and belly inclining to purple; the tail feathers are black, tipped with pale yellow; the quills are black, the third and fourth tipped on their outer edges with white; the five following with straw colour, but in some, bright yellow; the secondaries are tipped with white, each being pointed with a flat horny substance of a bright vermilion colour. These appendages vary in different subjects. This rare bird visits our island only at uncertain intervals. Their summer residence is supposed to be in the northern parts of Europe, within the arctic circle, whence they spread themselves into other countries, where they remain during the winter, and return in the spring to their usual haunts. The food of this bird is berries of various kinds; in some countries it is said to be extremely fond of grapes. Only this species of the chatterer is found in Eu. rope, the others are natives of America. See Plate I. Aves, fig. 5. A. caruncula, has a black bill, with a pendulous, expansile, moveable caruncle at the base, inhabits Cayenne and Brazil, and is about twelve inches long. The bill is an inch and half long, and black: at the base is a fleshy car buncle, hanging over it, like that of a turkey cock. The female is furnished with one as well as the male. These birds are said to have a very loud voice, to be heard half a league off, which is composed of merely two syllables, in, an, uttered in a drawling tone; but some have compared it to the sound of a bell.

AMPELITES, cannel-coal, a hard, opaque, fossil, inflammable substance, of a black colour. The ampelites examined by a microscope appears composed of innumerable very small thin plates, laid closely and firmly upon one another, and full of very small specks of a blacker and more shining matter than the rest. There is a large quarry of it in Alençon, in France. It is dug also in many parts of England; but the most beautiful is found in Lancashire and Cheshire: it lies usually at considerable depth. It is capable of a very fine polish, and is made into trinkets, and will pass for jet. Husbandmen dress their vines with it, as it kills the vermin which infests them: it is likewise used for dyeing the hair black,

AMPHIBIA, in natural history, a class of animals that live either on land or in water. The title Amphibia, applied to this

class of animals by Linnæus, may perhaps be considered as not absolutely unexceptionable; the power of living with equal facility both in land and water being not granted to all the animals which compose it; yet, since it is certain that the major part are found to possess that faculty in a considerable degree, the title may be allowed to continue. The Amphibia, from the peculiar structure of their organs, and the power which they possess of suspending respiration at pleasure, can not only support a change of element uninjured, but can also occasionally endure an abstinence which would infallibly prove fatal to the higher order of animals. It has been a general doctrine among anatomists, that the hearts of the Amphibia were, in the technical phrase, unilocular, or furnished with only one ventricle or cavity; a doctrine maintained by many eminent anatomists, and, in general, assented to by the greatest physiologists, as Boerhaave, Haller, &c. &c. and only occasionally called in question on viewing in some animals of this tribe a seemingly different structure. Thus the French academicians of the seventeenth century pronounce the heart of an Indian land tortoise, which they examined, to have in reality three ventricles instead of one. Linnæus, in his Systema Naturæ, acquiesces in the general doctrine, and accordingly, makes it a character of this class of animals. Among later physiologists, however, there are not wanting some who think it more correct to say, that the hearts of the Amphibia are in reality double, or furnished with two ventricles, with a free or immediate communication between them. The lungs of the Amphibia differ widely in their appearance from those of other animals; consisting, in general, of a pair of large bladders or membranaceous receptacles, parted, in the different species, into more or fewer cancelli, or subdivisions, among which are beautifully distributed the pulmonary blood-vessels, which bear but a small proportion to the vesicular part through which they ramify; whereas, in the lungs of the Mammalia, so great is the proportion of the blood-vessels, and so very small are the vesicles, or aircells, that the lungs have a fleshy rather than a membranaceous appearance. In the Amphibia, therefore, the vesicular system may be said greatly to prevail over the vascular; and in the Mammalia, or warm-blooded animals, the vascular system to prevail over the vesicular. Many of the Amphibia are possessed of a high degree of reproductive,

power, and will be furnished with new feet, tails, &c. when those parts have by any accident been destroyed. Many are highly beautiful in their colours, as well as elegant in their forms; while others, on the contrary, are, in the common acceptation of the words, extremely deformed, and of unpleasing colours. Their bodies are sometimes defended by a hard, horny shield, or covering; sometimes rather by a coriaceous integument; sometimes by scales, and sometimes have no particular defence or coating; the skin being merely marked by soft, pustular warts or protuberances, more or less visible in the different species. The bones of the Amphibia, except in a very few instances, are of a more cartilaginous nature than in either the Mammalia or Birds: many species are destitute of ribs, while others have those parts very numerous: some are furnished with formidable teeth; others are toothless: some are fierce and predacious; others inoffensive. Few, except among the serpent-tribe, are of a poisonous nature; the general prejudice against them having arisen rather on account of their form than from any real poisonous quality; but among the serpents, we meet with some species possessed of the most dreadful poison, as well as with the power of applying it with fatal force to the animals which they attack. The number of poisonous serpents is, however, not so great as was formerly imagined; perhaps not more than a sixta part of the whole number of kuown species being of that character. Among no animals do we meet with beings of a more singular form than in the Amphibia; some of which present appearances so unusual, so grotesque, and so formidable, that even the imagination of the poet or painter can hardly be supposed to exceed the realities of nature. The Amphibia in general are extremely tenacious of life, and will continue to move, and exert many of their animal functions, even when deprived of the head itself. The experiments which have been occasionally made on these subjects, can hardly be recited without horror. The natural life of some of the Amphibia, more particularly of the tortoise tribe, is extremely long; and even to the smaller tribes of frogs and lizards, a considerable space seems allotted. The same is also highly probable with respect to the serpent-tribe. By far the major part of the Amphibia are oviparous, some excluding eggs covered with a hard or calcareous shell, like those of birds; others, such as are covered only with a tough skin, VOL, L

resembling parchment; and in many, they are perfectly gelatinous, without any kind of external covering, as in the spawn of the common frog. Some few are viviparous; the eggs first hatching internally, and the young being afterwards excluded in their perfect form, as in the viper, &c. &c. In cold and temperate climates, most of the Amphibia pass the winter in a torpid state; and that sometimes in a degree of cold which would seem but ill calculated for the preservation of animal iife. The common large water-newt, in particular, is said to have been occasionally found completely imbedded in large masses of ice, in which it must have remained inclosed for a very considerable period; and yet, on the dissolution of the ice, has been restored to life. The Amphibia may be divided into four distributions, viz. Testudines, Ranæ, Lacertæ, and Serpentes; or Tortoises, Frogs, Lizards, and Serpents. The animals belonging to the three former of these divisions constitute the order entitled Reptilia, containing the Amphibia Pedata, or Footed Amphibia. The last division, or that of Serpents, constitutes the order Serpentes; containing the Amphibia Apoda, or Footless Amphibia.

AMPHITRITE, a genus of worms, of the order Mollusca: body projecting from a tube, and annulate: penduncles or feet small, numerous; feelers two, approximate, feathered; no eyes. There are seven species: of which the A. reniformis, with a rounded body and simple feelers, is three inches long, and inhabits the seas about Iceland. The body is of a most beautiful red: head defended by two semicircular arches: plumes fourteen, and alternately red and white: annulations of the body from 80 to 90, with each a minute tubercle on each side: tail pointed, and not jointed: tube red, tough, coriaceous, simple, and four inches long.

AMPHISBÆNA, in natural history, a genus of Serpents, of which the generic character is, body cylindric, equal; annular divisions on body and tail. According to Gmelin there are five species; but Dr. Shaw mentions two only, viz. the Alba and the Fuliginosa. The whole genus is allied to that of the Anguis, and in some degree to the Lacerta; it is, however, readily distinguished by the manner in which the exterior surface of its skin is marked in well-defined numerous circles or rings, completely surrounding the body, and divided in a longitudinal direction by still more numerous straight lines; thus forming so many square

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or parallelogramic scales. The alba is about 18 or 20 inches long, and of a proportional thickness. The head, which is covered with large scales, being but little larger in diameter than the body: the tail is short, terminating in a rounded extremity. The colour is, as the name imports, white, though in some instances it is tinged with a pale rose colour. The usual number of circles in this snake is about 223 on the body, and 16 on the tail. It is a native of South America, where it is found in woods, prey. ing on insects and worms. It is a harmless animal; but on being handled, it excites a slight itching on the skin, accompanied by small pustules, owing to an acrimonious moisture exuding from the animal. A. fuliginosa is at all times readily distinguished by its colours. There are about 230 rings on its body and tail. It is white, variegated with black or deep brown spots. The head is without spots. It is found in many parts of South America, resembling the alba in its manners, and being equally innoxious. The skin of the amphisbæna is remarkably strong and tenacious, and of a smooth or glossy surface: it is supposed to be able to perforate the ground with great facility, in the manner of earth worms, to obtain its food. The other species are found in America. See plate Serpentes, fig. 2.

AMPLITUDE, in astronomy, an arch of the horizon intercepted between the east or west point thereof, and the centre of the sun, star, or planet, at its rising and setting, and so is either north or south.

If the amplitude be taken from the rising sun, or star, it is called its rising or ortive amplitude; if when it sets, its setting or occasive amplitude. The sun's amplitude, either rising or setting, is found by the globes, by bringing the sun's place to the horizon, either on the east or west side, and the degrees from the east point, either north or south, are the amplitude required. To find the amplitude trigonometrically, say, as the cosine of the latitude radius :: sine of the present declination: sine of the amplitude. This problem is useful in navigation, to find the variation of the compass. Thus, in latitude 51° 31', when the sun's declination is 23° 28', then we say,

As 60. S. 51° 31' 10. &c. :: S. 23° 28′ : S. Amp. or, as 9.793990: 10. &c. :: 9.600118 : 9.806127 sine of 39° 47′ the amplitude sought: that is, the sun then rises or sets 39° 47' from the east or west point, to the north or south, as the declination is either north or south.

AMPLITUDE, magnetical, the different rising or setting of the sun, from the east or west points of the compass. It is found by observing the sun, at his rising and setting, by an amplitude compass. The difference between the magnetical amplitude and the true amplitude is the variation of the compass. If the magnetical amplitude be found to be 61° 55′ at the time it is

computed as above

to be............. 39° 47′

then the difference 22° 8' is the variation westward.

AMPLITUDE of the range of a projectile, the horizontal line subtending the path in which the projectile moved. See PRO

JECTILE.

AMPUTATION, in surgery, the cutting off a limb, or other part of the body, with an instrument.

AMULET, a charm, or preservative against mischief, witchcraft, or diseases. Amulets were made of stone, metal, simples, animals, and, in a word, of every thing which fancy or caprice suggested; and sometimes they consisted of words, characters, and sentences, ranged in a particular order, and engraved upon wood, &c. and worn about the neck, or some other part of the body. At other times they were neither written nor engraved, but prepared with many superstitious ceremonies, great regard being usually paid to the influence of the stars. The Arabians have given to this species of amulet the name of talisman.

All nations have been fond of amulets; the Jews were extremely superstitious in the use of them, to drive away diseases: and the Misna forbids them, unless received from an approved man, who had cured at least three persons before, by the same

ovate, obtuse, concave, inserted into the calyx; the stamina have filaments about 30, filiform, erect, shorter by half than the corolla, inserted into the calyx; anthers simple; the pistillum has a roundish, villose germ, simple style, of the length of the stamens, and headed stigma; the pericarpium is a roundish, villose, large drupe, with a longitudinal furrow; the seed is a nut, ovate, compressed, acute, with prominent sutures on each side, reticulated with furrows, and dotted with small holes. The nut of the almond is covered with a dry skin; that of the peach with a small pulp. There are seven species, of which we shall notice, 1. A. persica, with all the serratures of the leaves acute, and the flowers sessile and solitary. There are two varieties, viz. the peach-tree, with downy fruit, and the nectarine, with smooth fruit. 2. A. communis, the almond-tree, with the lower serratures of the leaves glandulous, and the flowers sessile and in couplets. The common almond has leaves which resemble those of the peach, but the lower serratures are glandular; they proceed from buds both above and below the flowers, and not, as in the peach, from the ends of the shoots above and not below the flowers. The form of the flowers is not very different; but they usually come out in pairs, and vary more in their colour from the fine blush of the appleblossom to a snowy whiteness. The chief obvious distinction is in the fruit, which is flatter, with a coriaceous covering, instead of the rich pulp of the peach and nectarine, opening spontaneously when the kernel is ripe. The shell is not so hard as in the first species, and is sometimes tender and very brittle; it is flatter, smoother, and the furrows or holes are more superficial. This tree is a great object in some parts of Italy, and in the south of France; and there are large plantations of it in Provence and Dauphine. It is common in China, and most of the eastern countries; and also in Barbary, where it is a native. In the time of Cato it seems not to have been cultivated in Italy; for he calls the fruit nuces Græcæ, or Greek nuts. With us it is valuable as an ornamental tree in clumps, shrubberies, &c. within view of the mansion; for it displays its delicate red-purple bloom in the month of March, when few other trees have either leaves or flowers. An almond-tree, covered with its beautiful blossoms, is one of the most elegant objects in nature. In a forward spring they often appear in February; but in this case the frost generally destroys

them, and they bear little or no fruit; but when they flower in March, they seldom fail to bear plenty of fruit, very sweet, and fit for the table when green; but they will not keep long. The amygdalus, or almondtree, is cultivated both for the advantage of the fruit, and as being highly ornamental in shrubberies, plantations, and other descriptions of pleasure ground, from its coming into bloom early in the spring. It is, however, less important in the former than the latter point of view, as the fruit is often liable to miscarry in this climate. All the species and varieties of this tree are deciduous, and of a hardy nature, thriving well in most common garden soils. Those of the tree kind frequently rise to fifteen or twenty feet in height, dividing into many spreading branches, which ultimately form beautiful heads, that are generally well adorned in the beginning of March with innumerable flowers, which continue in full bloom for a fortnight or three weeks, and are followed by the leaves, which are long and narrow, and the fruit takes its growth. This is downy, rather large, and of an oval form; consisting of a thick, tough, leathery substance, that embraces an oblong nut or stone, in which the kernel or almond is inclosed, which is the only part of the fruit that is capable of being made use of. The dwarf, shrubby sorts of this tree do not, however, in general, exceed three or four feet in height, having slender stems, which send forth a great number of small branches near to the ground; and in the single-flowered kind various suckers are frequently sent up from the root. And in both the double and single-flowered almond-tree, all the young branches are thickly beset with flowers in the spring, which, from their having a fine pale red colour, and continuing some time in blow, are highly ornamental. The single sort have their flowers coming out about the end of March, and the double kind in the beginning of April, each remaining about a fortnight in blow. The sorts chiefly cultivated for use in this country are, according to Mr. Forsyth, the tender-shelled almond, the sweet almond, the common, or bitter almond, the sweet Jordan almond, and the hard-shelled almond. Those propagated only for ornament are the dwarf and the double-flowering almonds.-Amygdalus Persica, or peach-tree. Its native country is not known. It came to the Romans from Persia, as its Latin name, malus Persica, indicates; and it has been cultivated from time immemorial in most parts of Asia ;