Al'goroth (Arab.), in chemistry, the submuriate of antimony, obtained as a white powder by mingling the chloride of mercury with water.

Alha'gi (Arab.), a genus of plants, the manna tree, believed by Arab writers to be a supernatural production. In hot weather the manna exudes from the leaves and branches. It is found in Mesopotamia, and other places in Asia and Africa.

Alhen'na, or Alken'na (Arab.), in botany, the plant Lawsonia alba, with the pulverized leaves of which the Egyptian women dye their nails yellow. Alhir'to (Arab.), in astronomy, a star of the third magnitude, in the constellation Capricornus.

Alicula'ria (Lat. drink), in botany, a genus of scale mosses, of the order Jungermanniaceæ.

Al'iform (Lat.), wing-shaped. Al'ioth (Arab.), in astronomy, a star of the third magnitude, in the constellation Ursa Major.

Al'iped (Lat. wing-footed), in zoology, an animal whose toes are connected by a membrane, which, like those of the bats, serve for wings.

Alis'ma, a genus of plants, the waterplantain, a type of the nat. order Alismaceæ, which contains three genera, Alisma, Damasoma, and Sagittaria; their flowers being in racemes, umbels, or pannicles.

Al'itrunk (Lat. ala a wing, and trunk), in entomology, the hinder segment of the body of an insect, with which the legs are connected.

Al'kali (Egyp. kali, a marine plant, the glass-wort), a term originally applied to certain plants of a soapy quality, but often used to designate their calcined produce, and in modern chemistry applied to bodies possessing similar chemical properties. It is the property of the alkalies to change vegetable blues to green, yellows to brown, and red to violet. The alkalies are arranged under three classes:-1. Those which have a metallic base combined with oxygen, soda, and lithia;-2. Ammonia, containing no oxygen; -3. Those contain ing oxygen, hydrogen, and carbon. The Alkaline earths arelime, baryta, and strontia.-Alkalescent, Alkaline, &c., are epithets applied to any substance of an alkaline nature.Alkaloid (Gr. like alkali) is a term applied to certain compounds obtained from organic bodies, which possess the alkaline principle, in order to distinguish them from the mineral alkalies, from which they differ in their general properties, but agree in their being composed of the

same elements. -Alkahest is the pretended universal solvent of the alchemists; the word being first used by Paracelsus, and adopted by his followers, to signify a universal dissolvent or liquor, which, if found out, was to have the power of resolving all compounds into their elementary constituents.

Alkalim'eter (alkali, and Gr. metron a measure), a graduated measure used by chemists for ascertaining the amount of alkali in any substance; the operation being called Alkalimetry.

Al'kanet, a purple dye, obtained from the root of the dyers' bugloss. Alkar'sine, in chemistry, a compound of hydrogen, carbon, arsenic, and oxygen.-Brande.

Al'kool (Arab.), a preparation of antimony, used by the ladies of the East in staining the eye-lids and eyelashes.

Al'lagite, in mineralogy, a massive opaque mineral, with a conchoidal fracture; it consists of manganese, silica, carbonic acid, and lime. Allaman'da (so called in honour of Dr. Allamand, of Leyden), a genus of plants, with yellow flowers, a native of Guiana; order Apocynaceæ. In medicine, an infusion of the leaves makes a valuable cathartic.

Al'lanite, an opaque mineral, found in West Greenland, so named from Thos. Allan, of Edinburgh; its component parts consist of oxide of cerium, oxide of iron, silica, lime, and alumina; sp. gr. 3.1.

Allantoi'dia (Gr. like a sausage), a genus of ferns, of the order Polypodi

aceæ.

Allantois (Gr. ut supra), in comparative anatomy, a thin transparent membrane, situate between the amnion and the chorion, or external and internal membrane, which contains the fœtus; the vesicle or sac which projects at the lower end of the alimentary canal in the embryo animal, organized by the hypogastric ar. teries and umbilical vein. Allantoid, having the appearance of allantois. -Allantoic acid is an acid found in the allantois and amnion of the fœtal calf, formerly called Amniotic acid. Allantox'icon (Gr. sausage poison), a poison exhibited in putrid sausages made of liver and blood. Allegro (Ital.), in music, a quick and sprightly movement.-Allegretto is the diminutive of allegro, and not so quick. Allegressimo is the superlative of allegro, and signifies very brisk and lively.

Al'lemande (Fr.), a slow piece of music. Allia'ria (Lat. garlic), a genus of plants, with a strong smell, like garlic; hedge garlic, or Jack-in-the-hedge;

order Cruciferæ.

Alligator (Port.), a large Saurian of the Crocodile family, which inhabits the American rivers.

Alliga'tor Apple, a species of the custardapple, which grows wild in the marshy grounds of Jamaica; the tree which produces it is the Annona palustris, which yields a kind of corkwood.

Allium (Lat. garlic), in botany, a genus of bulbous-rooted plants, which yield a strong aromatic smell, as the onion, garlic, leek, shallot, and numerous other pot-herbs of an edible character; order Asplodeleæ.

Allochroite (Gr. varied colour), in mineralogy, a species of dodecahedral garnet found in Norway, consisting of silica, alumina, lime, oxide of iron, oxide of manganese, and carbonate of lime. - Allochrous is an epithet applied to a mineral which has various colours.

Allogo'nus (Gr. a reciprocal angle), in mineralogy, a kernel-shaped crystal, with the form of a dodecahedron. Allopathy (Gr. other disease), in pathology, the art of curing disease by inducing symptoms different or otherwise from those of the primary disease; the ordinary medical practice as opposed to Homœopathy.-Allopathic pertains to allopathy, or the ordinary method of medical practice. Allophane (Gr. varied appearance), a mineral of various colours, found in Derbyshire and Thuringia; massive, and extremely brittle; consisting of alumina, silica, water, carbonate of copper, and sulphate of iron; sp. gr. 185.

Allos'orus (Gr. varied heap), inbotany, a genus of ferns, of the order Polypodiaceæ.

Allospermum (Gr. other seed), a genus of composite plants, of the sub-order Tubulifloræ.

Allotropy (Gr. another mode), in chemistry, the capacity to undergo a change of physical properties without change of medical composition. -Faraday.

Allox'an (Gr. other acidity), the action of nitric with uric acid.-Brande. Alluvium (Lat. a washing down), in geology, the increase of earth on a shore or on the bank of a stream by the deposit of earthy matter carried thither by water. - Alluvial is a term generally applied to those superficial stratified deposits of sand and gravel, in many places abounding with the remains of existing ani

mals and plants. Such deposits occur, in many parts, hundreds of feet above the level of the present ocean, or that of any existing water by which they could have been formed. In many places the alluvial formations are of considerable thickness, and, in some instances, partially consolidated into rock. When the Boulder formation is present, the alluvial beds overlie it; the term is therefore properly restricted to such stratified deposits as have occurred since the convulsive period, when the erratic boulders were spread over many portions of the earth's surface. See Diluvium.

Almacan'tar (Arab.), a small circle of the sphere parallel to the horizon, which passes through the centre of the sun. Almacantar staff, an instrument used to take observations of the

sun when it rises or sets. Al'magist (Arab. and Gr. megistos greatest), a collection of problems in astronomy and geography drawn up by Ptolemy of Egypt. Alma'gra (Sp.), in mineralogy, a fine deep-red ochre, which is very heavy and friable; it is used as a medicine and as a paint.

Al'ma-Ma'ter (Lat. a fostering mother), a term applied to a university, or to a college or seminary of education. Alman'dine (Fr. from Arab.), in mineralogy, an inferior kind of ruby; a precious garnet.

Almonds (Fr.), in anatomy, two round glands on the sides of the basis of the tongue; the tonsils.

Almug Tree (Heb.), a tree mentioned in Scripture, supposed to be the Shittim

wood.

Alnus (Sax.), a genus of trees allied to the birch; the alder; order Betulaceæ.

Aloe, pl. Aloes (Gr.), a tree or species of wood used in the East for perfumes. The medicinal gum, or inspissated bitter juice of this plant, is highly purgative. There are various species: as A. caballina, or horse aloes; A. spicata, or Cape aloes; and A. vu.garis, or Barbadoes aloes. - Alves wood is a resinous fragrant substance derived from the A. agallochum and the Aquillaria ovata. Aloetic acid is a precipitate obtained by heating nitric acid on aloes.

Alonso'a, a genus of flowering S. American plants, of the order Solaneæ. Alopecia (Gr. alopex a fox), in pathology, the falling off of the hair; bald

Alo'sa, a migratory fish, the shad, of the Clupeæ or Herring family. Alpa'cha, in zoology, a species of Peruvian sheep, the llama, of the order Ruminantia, and tribe Camelidæ its fur or wool is fine and soft, and of late years has become of great importance as an article of

commerce.

Alpes'tris (from the Alps), in botany, an epithet applied to those plants which grow on elevated mountains.

Alphon'sin, in surgery, an instrument for extracting balls, called after Alphonso Ferrier, the inventor.

Alphon'sin Tables, a series of astronomical tables, compiled in 1252, by Aphonso XII., King of Castile and Leon.

Alpine (Lat. Alpinus), in natural history, an epithet applied to the Alps or any mountainous country, or to the productions thereof.

Al'quifou, in mineralogy, a kind of lead ore, found in Cornwall, commonly called potter's ore, because used by them to give a green varnish to their wares.

Alsine (Gr. a shady grove), a genus of herbaceous plants (chickweed), of the order Caryophyllaceæ.

Alsodei'a (Gr. leafy), a genus of Madagascar plants, of the order Violaceæ or Violets, and of the tribe Alsodineæ. Alt-az'imuth (Gr. and Arab.), in astronomy, a term applied to an instrument for observing both the altitude and azimuth of a celestial body.

Alter'ative (Lat. to alter), in pathology, a medicine which gradually re-establishes the healthiness of the natural functions of the body.

Alter'nant (Lat. alter another), in mineralogy, an epithet applied to a rock which is composed of alternating laminæ or layers.

Alternanthe'ra (Gr. alternate anthers), a genus of plants whose stamens are alternately fertile and barren; order Amaranthaceæ.

Alter'nate Genera'tion, in zoology, a form of reproduction in which the young do not resemble the parent of the animal, but the grand-parent.

Althæ'a (Gr. to heal), a genus of plants, including the hollyhock (A. rosea), and the marshmallow (A.officinalis); order Malvaceæ.

Al'theine, in chemistry, the name of a salifiable base found in Althea officinalis.

Al'tica (Gr. nimble), in entomology, a genus of minute coleopterous insects, which jump to a great height, and with amazing quickness.

Altim'etry (Lat. and Gr. measuring of heights), the science or art of measur

ing altitudes, generally by means of the quadrant, whether accessible or otherwise.

Al'tingia (so called from Alting, the German botanist), a magnificent class of trees, which attain a great height and magnitude, especially the species Altingia excelsa; order Coniferæ. Altiros'tres (Lat. high-beaked), in ornithology, a name given to those scansorial or climbing birds, which have their beaks elevated but not large. Alto (Ital. high), in music, the higher part of the gamut; the counter-tenor, or highest natural pitch of the adult male voice, usually from F, the fourth line in the base, to C, the third space on the treble.-Altissimo is the superlative of alto; the musical scale in altissimo commencing with F, the octave above the fifth line in the treble. Alto-clef is one of the names of the C clef, when placed in the third line.

Altom'eter (Lat. and Gr. a measurement of heights), an instrument for measuring heights and distances; a name for the theodolite.

Al'to-relie'vo (Ital. high relief), in sculpture and architecture, that species of ornamentation which projects from the surface to which it is attached nearly as much as if the figures were isolated from the body of the work. Alto-rip'iendo (Ital. from Lat. altus high), in music, the tenor of the great chorus:

Alu'del (Lat. without lute), in chemistry, a kind of subliming pot, without a bottom. In operating, the aludels are fixed into one another, as many as there is occasion for, without luting. At the bottom of the furnace there is a pot which holds the matter to be sublimed, and at the top there is a head to retain the flowers that rise up. Quincy.

Al'ula (Lat. and Fr. a wing), in ornithology, the bastard wing or group of feathers attached to the joint of the carpus. In entomology, a small scaly convexo-concave appendage fixed to the base of the wing of some dipterous insects.

Al'um (Lat. alumen), in mineralogy, an earthy chalk, a sulphate of alumina, or of potash. It occurs as an efflorescence in sulphureous shales, lavas, &c., or as stalactites in delicate capillary crystals. It consists of sulphuric acid, alumina, potash, and water.-In medicine, A. exsiccatum, dried alum; A. rupeum, rock alum; and A. Romanum, Roman alum. Alu'mina (Lat. alumen), in chemistry, the oxide of Aluminum, which forms the basis of all clays, and to which

the plastic property of clay is owing. -Aluminum, in a state of purity, resembles platina in appearance; but when burnished it has the lustre of polished tin.

Al'umite, in mineralogy, a hard variety of alum stone, sometimes used for mill-stones.

Alum-meal, a name for the granular alum which occurs in the manufacture of salt.

Alum'nus (Lat.), one educated at a college or public institution, of which he is called the Alumnus.

Alum-slate, or Schist, in mineralogy, a variety of clay-slate or shale, which, when exposed to the action of the atmosphere, effloresces into soft delicate fibres of the ferro-sulphate of iron. Alum-slate occurs near Whitby, in Yorkshire, and at Hurlet and Campsie, near Glasgow, at which large manufactories have been long in existence. Alum-stone is a crystallized mineral, which occurs at La Tolfa, in Italy; it consists of sulphuric acid, alumina, potash, and iron. Alu'ta (Lat.), in mineralogy, a sort of leather stone, which is soft and pliable, and not laminated.

Alva-Mari'na (Lat, a sea-weed,, in commerce, the scientific name for certain dried sea-weeds, which in the arts are used for stuffing cushions, beds, bolsters, &c.

Alveoli (Lat.), in anatomy, the sockets of the teeth; the alveolar processes. In botany, the small honey-comblike cavities, which are symmetrically arranged on certain plants. Alveolar, belonging to the sockets in which the teeth are fixed.

Alveolites (Lat. honey-combed, and Gr. a stone), in geology, a genus of fossil zoophytes, composed of small hemispherical cells.

Alvus (Lat.), the abdomen or lower intestines. In pathology, Alvine concretions are those formed in the large intestines by accumulation of fæces. Amal'gam, or Amalgama (Gr. a welding together), the mixture of metals by amalgamation, particularly by the agency of mercury. Native amalgams in Sweden, Hungary, and other places, in a semi-fluid, massive, or crystallized state, are composed of mercury 64, and silver 36.

Amal'thus, a fossil Cephalapod; a genus of the Ammonite family. Aman'dola, in mineralogy, a variety of green marble.

Amanita (Gr. a fungus), a genus of mushrooms, said to be poisonous.Amanitine is a name of the venomous principle contained in poisonous fungi.

Amarantha'cese (Gr. ever-blooming), a nat. order of apetalous plants, of which the Amaranth is the type: "Immortal amaranth! a flower which

once

In Paradise, fast by the tree of life, Began to bloom."-Milton.

The principal species cultivated in this country are, the globe amaranth, the cockscomb, love-lies-bleeding, and the prince's feather.-Amaranthine is a general epithet applied to an unfading flower.

Amaryllida'cesæ, or Amaryllid'ee (Lat.), a nat. order of indigenous, bulbousrooted plants, of which the Amaryllis is the typc. This order contains the narcissus, the daffodil, the belladonna, and the blood-flowers. Amasthen'ic (Gr.), in optics, an epithet applied to a lens photographically perfect, or which unites all the chemical rays into one focus.

Amauro'sis (Gr. obscure), in pathology, a disease of the eye, attended with weakness or loss of vision, the retina and optic nerves being paralytically affected; sometimes called Gutta

serena.

Amazon Stone, a species of stone found on the river Amazon, and also in New Zealand and other South-Sea Islands; it is manufactured into hatchets and other warlike implements; also a green variety of felspar, found on the Ural Mountains. Amber (Arab.), in mining, a fossil, yellow-coloured resin, easily cut with a knife, and supposed to be of vegetable origin. Its component parts are carbon, hydrogen, oxygen, and ashes. It is highly electric, and is called in Greek electron, whence the term electricity. Insects are frequently found enclosed within amber. In the arts it is extensively used, especially as mouth-pieces of tobacco pipes. Am'bergris (Arab. and Fr. gris grey), a substance used as a perfume, found in the intestines of the spermaceti whale, and considered to be a morbid product analogous to biliary calculi.

Ambig'enal (Lat. double-kneed), in geometry, a term applied to one of the triple hyperbolas of the second order, having one of its infinite legs falling within an angle formed by the asymptotes, and the other without.

Am'bitus (Lat.), in conchology, a term applied to the outline or circumference of the valves. In botany, the encompassing border of a leaf.

Amblyg'onite (Gr. oblique-angled), a crystallized mineral, of a greenishwhite colour, consisting of alumina,

lithia, and phosphoric acid; sp.

gr. 3.

Amblyop'ia (Gr. dull-eyed), imperfect sight, incipient amaurosis. Amblyopus (Gr. ut supra), a genus of eel-like fishes, with very minute eyes; family Gobideæ.

Amblypterus (Gr. obtuse-finned), in palæontology, a genus of fossil fishes, with obtuse rounded fins.

Amblyrhynchus (Gr. obtuse-snouted), in herpetology, a genus of spinybacked lizards; fam. Iguanidæ. Ambon (Gr.), in anatomy, the margin or tip of a socket, in which the edge of a bone is lodged.

Amboy'na-wood, in the arts, the name of a beautifully mottled wood, the produce of the Pterospermum Indi

сит.

Ambre'ic Acid, in chemistry, an acid formed by the combination of ambrein with nitric acid.--Ambreate is a salt formed from the combination.

Am'brein, in chemistry, the fatty matter of ambergris, changed by nitric acid into ambreic acid.

Ambrosia'ceæ (Gr. immortal), an order of annual composite plants, of which Ambrosia is the type.

Ambulac'ra (Lat. an alley), in zoology, the narrow longitudinal portions of the echinus or sea-urchin shell.

Ambulato'res (Lat. walkers), in ornithology, a term applied to an order of walking birds, which are nearly feathered to the toes.

Amel, the material used in the art of enamelling.

Amenorrhœ'a (Gr.wanting the monthly course), in pathology, irregularity or defectiveness of the menstrual discharge.

Amen'tia (Lat.), in pathology, want of intellect; madness; idiotcy. Amen'tum (Lat. a thong), in botany, a term applied to the male inflorescence of the birch, willow, or hazel; a form of inflorescence resembling a pike. Ametabolia (Gr. without change), in entomology, a class of insects which do not undergo the metamorphosis of other insects.

Am'ethyst (Gr. not intoxicating), in mineralogy, a precious stone, of two varieties, one an adamantine spar or corundum, the other a beautiful violet-coloured transparent quartz; it consists of silica, alumina, manganese, and oxide of iron.

Amhers'tia, in botany, a genus of fine flowering plants, so named in honour of the Countess Amherst; order Leguminosæ.

Amianthus (Gr. undefiled), a variety of the mineral asbestos, which occurs in long flexible fibres, and when

woven in cloth is capable of resisting the action of fire; it is composed of silica, magnesia, lime, and alumina. -Amianthoide (Gr. like the amianthus), a mineral of an olive-green colour and silky lustre, which occurs in long capillary filaments; its component parts are silica, oxide of iron, lime, manganese, and magnesia. Am'miolite, in mineralogy, an antimoniate of quicksilver, imported as a kind of red powder from Chili. Am'mite (Gr. sand), in mineralogy, a variety of sandstone, oolite, or roe

stone.

Ammocæ'tes (Gr. sand-bed), a genus of round-mouthed fishes, which bury themselves in sand, and have wormlike habits; they have the lowest grade of vertebral organism.

Am'mochryse (Gr. gold-sand), in mineralogy, a soft yellow-looking stone, found in Germany.

Ammodytes (Gr.sand-ducker), a genus of apodal fishes, the sand-eels. Ammonia (so called from the temple of Ammon, in Libya, which was visited by the camels from whose dung the muriate of ammonia was first produced), in chemistry, an important volatile alkali, obtained from the decomposition of animal matter, or artificially by subjecting bones, horns, hoofs, &c., to heat, in iron cylinders; or from portions of vegetable matter which contain nitrogen. Ammonia chemically consists of 3 atoms of hydrogen, I of nitrogen; or hydrogen 17.64 and nitrogen 82°36. When moderately heated ammonia expands, but by a strong heat it is decomposed, and when decomposed it is found to consist of three volumes of hydrogen and one of nitrogen, condensed into one volume, or if estimated by the weight, according to the atomic system of chemistry, we shall find: 3 atoms of hydrogen 3... 17.64 I atom of nitrogen 14... 82.36

Equivalent to

17...100

The salts of ammonia are decomposed by the fixed alkalies and alkaline earths, with the evolution of ammonia. When a salt of magnesia, and a soluble phosphate, are added to them, precipitation takes place, and crystals are the result, which are compounds of the phosphate of ammonia and the phosphate of magnesia. The proper application of ammonia to peat land is very important. Ammonia has a variety of compounds, of which the following are among the most important:-Acetate of ammonia, a salt produced by the