capital.-In mechanics, a large and strong axle.

Shale (Germ. schalen to peel off), in geology, a term applied to all argillaceous or clayey strata which peel off in thin laminæ.

Shells, in the science of gunnery, hollow iron balls to throw out of mortars or howitzers; - Message shells are howitzer shells fired into a garrison or camp to communicate information;-Shrapnel shells are of a peculiar construction, invented by General Shrapnel.

Shingle, in geology, loose imperfectlyrounded stones and pebbles. Shorlite, a mineral occurring at Altenburg, in Saxony.

Sial'ogogue (Gr. sialon saliva, and agogos drawing forth), a medicine that increases the flow of saliva and other fluids.

Sib'erite (from Siberia), in mineralogy, rubellite, or red tourmaline. Sibthorpia'cese (from Dr. Sibthorp of Oxford), an order of exogenous plants, consisting of herbs with alternate undivided leaves.

Sidera'tion (Lat. sidus a star), in pathology, a name given to erysipelas of the face or scalp.

Side'real (Lat. sideralis, from sidus), pertaining to the stars. The sidereal day is the time in which the earth makes a complete revolution on its axis according to the fixed stars, being nearly four minutes shorter than the solar day. The sidereal year is the time in which the earth performs a complete revolution in its orbit, in reference to the fixed stars, which is equal to 365 days 6 hours 9 minutes 9.6 seconds.

Sid'erite (Gr. sideros iron), in mineralogy, the loadstone; a phosphate of iron.

Siderog'raphy (Gr. sideros steel, and grapho to write), the art or practice of engraving on steel.

Sider'olites (Gr. sideros, and lithos a stone), a name given to those nummulites which have a stellated ap

pearance.

Sideroschis'tolite (Gr. sideros, schistos fissile, and lithos a stone), a black mineral which occurs in small sixsided prisms, composed of protoxide of iron, silica, alumina, and water: sp. gr. 3.0; H = 2.0-3.0.

Sid'eroscope (Gr. sideros, and skopeo to view), an instrument for detecting small particles of iron.

Si'enite (from Siene in Egypt), in mineralogy, a rock or stone compounded of quartz, felspar, and hornblende.

Sigilla'ria (Lat. sigillum a seal), in

geology, a large genus of fluted tree stems, with seal-like punctures on the ridges.

Sigmoid (like the Greek letter sigma), in anatomy, a term applied to various structures in the body.

Sign (Lat. signum), in pathology, anything by which the presence of disease is known. In astronomy, the twelfth part of the ecliptic.

Silex (Lat. flint), the siliceous material which constitutes the principal portion of most of the hard stones that compose the crust of the globe.

Silhouette' (Fr.), representation of an object, or a small portrait, filled in with a black colour; a profile likeness by shade.

Silica, the scientific term for silex. Silicalca'reous, consisting of silica and calcareous matter.

Silicate (Lat. Silex, which see), a compound of silicic acid and a salifiable base. Silicate of cerium is a mineral which occurs in regular hexagonal prisms of a pale yellowish-brown colour. The silicates constitute the greater number by far of the hard minerals which encrust the globe. Silicical'ce (Lat. silex, and calx lime), a mineral substance which occurs in amorphous masses under strata of limestone in Provence. Silicif'erous (Lat. silex, and fero to produce).-Siliciferous hydrate of alumina, a mineral which occurs in white and nearly opaque masses, perfectly sectile, and composed of alumina, silica, and water: sp. gr. 2'06-211. -Siliciferous oxide of manganese, a mineral which occurs massive, of a pale rose-red colour: sp. gr. 3°5; H = 5.0.

Silicification (Lat. silex), the conversion of a substance into stone by the infiltration of siliceous matter.

Silicimu'rite (Lat. silex, and muria brine), an earth composed of silica and magnesia.

Silic'eous, Silic'ious (Lat. Ainty), containing silica. - Siliceous oxide of zinc is a mineral which occurs crystallized, stalactitic, mammillated, botryoidal, and massive; composed of oxide of zinc, silica, and water: sp. gr. 33-36; H = 5.0.

Sil'icite, a mineral composed of silica, alumina, lime, and soda.

Sili'cium, in chemistry, the metallic base of silica.

Sil'icon (Lat. silex), an elementary substance of a dark brown colour, incombustible in atmospheric air and oxygen gas, and infusible by the blowpipe.

Silic'ula, or Sil'icule (Lat.), in botany, a dry bivalve pericarp, divided in

teriorly by a membranous septum, which contains the seeds.

Sil'iqua (Lat.), in botany, the pod, husk, or shell of plants of the Pulse kind, as the Bean, Pea, &c.-In gold refinery, a carat, of which six make a scruple. Sillimanite, a mineral of a dark grey colour and vitreous lustre, so called from Professor Silliman, of Connecticut, composed of alumina, silica, oxide of iron, and water: sp. gr. 3.41; H=6.0.

Sillon (Fr.), in fortification, a work raised in the middle of a ditch, in order to defend it when too wide.

Sil'phidae (Gr. silphe a grub), a family of coleopterous insects, of which the Silpha is the type.

Silurian (from the ancient Silures of Wales), in geology, noting a series of rocks, or a group of fossiliferous strata, such as are found in Wales. The system is divided into the Ludlow rocks, Wenlock limestone, Caradoc sandstone, and Llandeilo rocks. Siluridae (Gr. silouros), a family of malacopterygious fishes, in which the body is mailed or naked, and without true scales: Silurus, or Cat-fish, is the type and genus.

Sil'vanite (Lat. silva), in mineralogy, a very sectile mineral of a metallic lustre, and composed of tellurium, gold, and silver.-Dana.

Silver (Ger. silber), in metallurgy, a white, malleable, ductile, and tenacious metal, of a brilliant lustre when polished. Silver is one of the fiftyfive simple or elementary bodies, and included in the subdivision termed metals nearly white: sp. gr. when melted, 10°47; fusing point, 1873° Fahr.; symb. Ag; equiv. 108.-German silver, an alloy much used for the manufacture of domestic articles, such as forks, spoons, &c.; its ingredients being copper, nickel, and

zinc.

Silvic, in chemistry, applied to an acid which, with pinic acid, constitutes the greater portion of common rosin. Simaru'ba (Caribbean name), in medicine, the bark of the root Quassia simaruba, used as a tonic.

Simaruba'ceæ, a nat. order of exogenous plants, consisting of trees or shrubs, of which the Simaruba is the type.

Sim'ia (Lat. flat-nosed), in zoology, a genus of animals resembling man, as the Baboon, &c. The facial angle of the Orang-outang, a genus of Simia, or Ape-monkey, is 65°.

Sim'iade (Lat.), a family of the Quadrumana, distinguished by having eight cutting teeth, four canines, and twenty grinders.

Simoom (Ind.), a hot, suffocating wind which blows occasionally in Africa and Arabia.

Simple Equation, in algebra, an equation in which the unknown quantity is only of one dimension, as 7 ax = b; 5x-ax bc.

Sina'pis (Lat. and Gr. mustard), a genus of cruciferous plants, from the seed of which is produced the well-known article mustard.-Sinapine is a peculiar principle extracted from mustard seed. It is supposed to contain sulphur, carbon, nitrogen, hydrogen, and oxygen.

Sina'pium (Lat. sinapis), in pharmacy, an infusion or decoction of mustard. Sinap'oline (Lat. sinapis), a compound obtained by depriving oil of mustard of its sulphur by the action of baryta. Sin'ciput (Lat.), in anatomy, the fore part of the head.

Sindon (Lat. fine linen), in surgery, a small rounded pledget of linen, with a thread attached thereto.

Sine (Lat. sinus), in geometry, a straight line drawn from one extremity of the arc of a circle, perpendicular to the radius, passing through the other extremity. In trigonometry, a right line drawn from one end of an arc perpendicular upon the diameter.The cosine of an arc is simply the sine of its complement.

Singul'tus (Lat. a sob), in pathology, a convulsive motion of the diaphragm; the hiccough.

Sin'ical Quadrant, an instrument formerly used for taking the altitude of the sun.

Sin'namine, a crystallized substance obtained from the oil of mustard. Sinus (Lat. an indentation), in anatomy, a cavity in a bone widest at the bottom. In surgery, an elongated cavity containing pus.

Sin'oper, Sin'ople (Gr.), in mineralogy, a red ferruginous quartz; a species of earth.

Siphon (Gr.), a bent tube used for drawing off liquids from casks.-Siphon-gauge is a glass siphon partly filled with mercury, used for indicating the degree of rarefaction which has been produced in the receiver of an air-pump. Siphon'ifers, an order of testaceous Mollusca which have a siphon contained within a polythalamous shell.

Si'phuncle, a small siphon.
Siri'asis (Gr.), in pathology, a stroke of

the sun; inflammation of the brain. Sir'ius (Lat.), a star of the first magnitude in the constellation Canis Major, or the Great Dog; the brightest star in the heavens.

Sirocco (Ital.), a periodical warm south wind, which generally blows in the south of Italy about Easter.

Sismon'dine, a mineral of a deep green colour, composed of silica, alumina, protoxide of iron, and water: sp. gr. 3.56.

Sitiology (Gr. sition food, and logos, a discourse), a treatise upon aliments. Sitti'næ (Gr. sitta a woodpecker), a sub-family of the Certhiadæ, or Creepers, of which Sitta is the type. Sivathe'rium (Siva a district in India, and Gr. therion a wild beast), in geology, an extinct genus of ruminant animals of great size.

Skeletology (Gr. skeletos dry), in anatomy, a treatise on the solid parts of the body.

Skeleton (Gr. skeletos), the bones of an animal body separated from the flesh, and retained in their natural position. Skew Bridge, in engineering and architecture, a kind of bridge introduced upon railroads, when the railway intersects obliquely any existing communication.

Skol'ezite. (See Scolecite.)
Skorodite. (See Scorodite.)
Skorzite, in mineralogy, a variety of
epidote.

It

Slate (Fr. éclater to split; Irish sglata a tile), in geology, a dark-coloured stone of a structure termed schistose, which admits of being split into thin layers of considerable extent. consists of silica, alumina, oxide of iron, manganese, potash, carbon, and water. The Slate system is divided into-Plynlimmon rocks, consisting of grauwacke and grauwacke slate; the Bala limestone, a dark limestone associated with slate, containing shells and corals; the Snowdon rocks consist of fine-grained slates, and of grauwacke and conglomerate.

Slubbing Machine, a machine used in the manufacture of woollen, for drawing out into slubs the rolls of wool. Slugs, in gunnery, pieces of metal discharged from a gun.

Smalt (Germ. schmalz), a beautiful blue substance made by fusing glass with oxide of cobalt, by which a blue glass is formed, which, after being pulverized, is employed for relieving the yellow tint of writing paper and linen, staining glass, porcelain, and earthenware.

Smaragd, Smaragdus (Gr.), in mine

ralogy, a name for the emerald.Smaragdine, made of or resembling emerald.

Smaragdite (Gr.), in mineralogy, a green diallage of a brilliant or emerald green colour.

Smelt (Germ. schmelter to melt), in metallurgy, to melt, as ore, for the purpose of separating the metal from extraneous substances.

Smilacese, in botany, an order of dictyogenous herbaceous plants, so called from Smilax, the Greek name given to several plants, more especially to the Yew-tree.

Smyrnese, a family of umbelliferous plants, of which Smyrnium, or Myrrh, is the genus.

Snifting Valve, a valve in the steamengine, so called because it makes a noise like a man snifting with a cold.

Snow (Sax. snaw), in meteorology, congealed watery vapour which falls from the bosom of the atmosphere in white flakes.-Snow-line is the elevation at which mountains are covered with perpetual snow.

Soap (Lat. sapo, Gr. sapon), a chemical compound of oily substances boiled with potash or alkaline solutions, and prepared for the purposes of washing, shaving, &c.-Soap-stone, in mineralogy, a magnesian stone, apparently unctuous to the touch. It is composed of silica, alumina, magnesia, potash, oxide of iron, and water: sp. gr. 2.4. Socle (Ital. zoccolo a shoe), in architecture, a square member of less height than its horizontal dimension, serving to support vases or other ornaments. Soda (Ital. and Sp.), in chemistry, a mineral or fixed alkali; an oxide of sodium; natron. In commerce, it generally occurs as a carbonate, either pure, or in the impure forms of barilla and help. The carbonate of soda is an article of the greatest importance in the soap, glass, and other manufactures.-Soda-water, a refreshing drink formed by dissolving carbonate of soda in water, and saturating the solution with carbonic acid.

Soda Alum, in mineralogy, a crystalline mineral, soluble in water, and composed of sulphate of soda, alumina, and water.

Soda Ash, in chemistry, an impure carbonate of soda.

So'dalite (soda, and Gr. lithos a stone), a mineral composed chiefly of silica, alumina, and soda.

So'dium, in mineralogy, the base of the alkali soda, and one of the fifty-five elementary substances: it is a metal possessing a strong lustre, and a colour very analogous to that of silver;

it fuses at 200o, and rises into vapour at a red heat: sp. gr. 0.97.

Solana'cese (Lat. solanum nightshade), a nat. order of exogenous plants, consisting of herbs or shrubs, of which Solanum is the genus.

Sola'nia, in chemistry, the active principle of Solanum dulcamara, or Woody Nightshade.

Sol'anine (Lat. solanum), a vegetable principle which occurs in several species of Solanum.

Sola'num (Lat.), in botany, a genus of plants of which there are different species; as, S. tuberosum, the plant of which the Potato is the root; S. nigrum, the Common Nightshade; S. lycopersicum, Love-apple or Tomato. Solar (Lat. sol the sun), an epithet of frequent use in astronomy and chronology, as solar month, solar year.The solar system is that part of the universe which comprises the sun and the various heavenly bodies that revolve around him.-Solar cycle is a period of twenty-eight years, which being elapsed, the Dominical or Sunday letters return to their former place, and proceed in the same order as before.-Solar month is the time which the sun takes to run through one entire sign of the ecliptic, the mean quantity of which is 30 days, 10 hours, 29 min., 5 sec. In anatomy, solar plexus is an assemblage of ganglia, which are distributed to all the divisions of the aorta.

Solen (Gr. a channel), a surgical machine in which a broken leg is placed.

Solfatara (Ital.), in geology, a volcanic vent, from which sulphureous gases are emitted.

Solid (Lat. solidus), in geometry, a body which has length, breadth, and thickness. A solid angle is an angle formed by three or more plane angles meeting in a point, and of which the sum of all the plane angles is less than 360°. A regular solid is one which is terminated by equal and similar planes, so that the apex of their solid angles may be inscribed in a sphere. In military science, solid square is a square body of troops; a body in which the ranks and files are equal.-In anatomy and medical science, the solids are the bones, flesh, &c., of animals, distinct from the fluids.

Solidun'gulates (Lat. solidus, and ungula a hoof), a tribe of Mammalia, which includes those with only a single hoof on each foot, as the Horse.

Sol'ipeds (Lat. solidus, and pedes feet), a class of animals with a single hoof

Solstice (Lat. solstitium, from sol the sun, and sto to stand), the time at which the sun is at the greatest distance from the equator; midsummer and mid-winter.-Solstitial, belonging to or happening at the solstice.Solstitial points, the two points in the ecliptic at which the sun arrives at the time of the solstice.

Solution (Lat. solutio, from solvo to loosen), the act of separating the parts by means of a fluid; thus, in dissolving salt in water we obtain a solution of the salt.-In pathology, the termination of a disease.-In surgery, solution of continuity is a dissolving the unity and continuity of parts, as in wounds, fractures, &c.In mathematics, solution is the geometrical construction of a problem, or the algebraical expression of its conditions by an equation which gives the value of the unknown quantity. Solvent (Lat. solvo to dissolve), in chemistry, any fluid or substance which renders other bodies liquid. Somatology (Gr. soma the body, and Logos a discourse), the doctrine of material substances; a treatise on the human body. Som'ervillite, a crystallized mineral which occurs among the ancient scoriæ of Vesuvius.-Dana. Sommite, a mineral, so called from Monte Somma, a part of Vesuvius, where it occurs.

Somnop'athy (Lat. somnus sleep, and Gr. pathos a passive state), a kind of mesmeric sleep; somnambulism. Sona'ta (Ital. sonare to sound), a tune or composition to be performed wholly by instruments.-Sonatina, a short and simple sonata. Sonom'eter (Lat. sonus sound, and Gr. metron a measure), an instrument for measuring sounds, or the intervals of sounds.

Sopra'no (Ital.), in music, the highest vocal part.

Sorbic Acid, an acid found in many fruits, particularly the apple, but most commonly obtained from the Sorbus aucuparia.

Sorbine, a crystalline, saccharine substance obtained from berries of the mountain-ash.

Sordaw'alite, a mineral occurring in opaque, greyish, or bluish - black coloured masses, so called from Sordawala, in Finland. Compositionsilica, alumina, peroxide of iron, magnesia, phosphoric acid, and water: sp. gr. 2'53; H=2.5-3.0. Sordes (Lat.), in pathology, the viscid matter discharged from ulcers, &c. Soric'idæ, in zoology, a family of Mammals, comprehending the Shrews, Moles, and Hedgehogs, of which Sorex, the Shrew, is the type.

Soro'sis (Gr.), in botany, a sort of fleshy fruit formed of compound receptacles. Soru'bine (Lat.), in ichthyology, a subfamily of the Cobitidæ, consisting of fishes with large lengthened heads, of which the Sorubium is the type.

Sorus (Gr. soros a heap), in botany, one of the small clusters of capsules or fruit dots on the back of the fronds of ferns.

Sospiro (Ital.), in music, a breathing rest.

Soteriology (Gr. soterios salubrious, and logos a discourse), a treatise on health, or the science of preserving health.

Sotto-voce (Ital.), in music, with a softened or under voice.

South (Sax.), one of the cardinal points of the compass; the direction in which the sun always appears at noon to the inhabitants of the northern hemisphere,

Spadix (Lat.), in botany, a form of inflorescence in which the flowers are arranged round a fleshy rachis.

Spandrel, in architecture, the triangular space included between the curve of an arch and the square drip-stone over it.

Spargelstein (Germ.), in mineralogy, a variety of apatite of a wine-yellow colour; asparagus-stone.

Sparia'ne (Lat.), in ichthyology, a subfamily of the Chætodonidæ.

Spar'idæ, a family of acanthopterygious fishes, resembling the Perches.

Spartalite (Gr. spartos scattered, and lithos a stone), in mineralogy, red oxide of zinc, translucent and brittle: sp. gr. 5'4; H = 4.0.

Spasm (Gr. spao to draw), in anatomy, an abnormal involuntary contraction of muscular fibres.

Spasmology (Gr. spasma spasm, and logos a discourse), a treatise on convulsions.

Spathe (Gr. spathe a broad blade), in botany, a large coloured bract which encloses a spadix.

Spathic (Germ. spath spar), in mineralogy, foliated or lamellar.

Spathose Iron (Germ. spath), a mineral of a lamellar or prismatic structure, and a pearly lustre, composed of protoxide of iron, carbonic acid, oxide of manganese, and lime: sp. gr. 3.6; H = 3.5.

Spatulate (Lat. spatula a broad leaf),

in botany, applied to leaves narrow at the base, and widening towards a broad-crowned top.

Spavin (Fr.), in farriery, a disease of horses which generally causes lame

ness.

Species (Lat.), in botany and zoology, a class comprehended under a genus. A male and female of the same genus may procreate, and the offspring is called a mule or hybrid. Hybrids in the vegetable kingdom produce endless varieties, but not new species.In mineralogy, species is determined by the form of the primitive crystal, or the ingredients of which a mineral is composed.

Specific (Fr.), in pathology, an efficacious medicine appropriated to the cure of some particular disease. Specific Gravity, in chemistry and physicology, a term of very general application, as denoting the relative proportion of the weight of bodies of the same bulk as compared with rain water. Specific gravities are usually stated in whole numbers and decimal parts, that of water being stated as I, except as relates to the gases, when the weight of atmospheric air is the unit. The following is a list of the specific gravities of the most common substances :

Gypsum Honey

loose