being converted into vapour, and afterward condensed drop by drop.

DIVELLENT, from divello, to tear asunder; that which causes separation.

DIVERGENT, from di, in different directions, and vergo, to bend ; tending to various parts from one point.

DODECAHEDRON, from dúdɛka, twelve, and Edpa, a base or side; a solid figure contained by twelve equal sides. DYNAMICS, -ICAL, from dúvaus, power; that branch of mechanical science which treats of moving powers, and of the action of forces on solid bodies, when the result of that action is motion.

E.

EBULLITION, from ebullio, to boil; the act of boiling. EDUCT, from e, out of, and duco, to draw; anything separated from another with which it previously existed in combination.

EFFLORESCENCE, from effloresco, to blow as a flower; the formation of small crystals on the surfaces of bodies, in consequence of the abstraction of moisture from them by the atmosphere.

ELASTICITY, IC, from 2aúvw, to push or thrust; the property bodies possess of resuming their original form when pressure is removed.

ELECTRICITY, from λekтроv, amber; the name of a power of matter, which produces a variety of peculiar phenomena, the first of which were observed in the mineral substance called amber; the laws, hypothesis, and experiments by which they are explained and illustrated, constitute the science of electrity.

ELECTRODE, from λεктроv, electricity; and ddos, a way; the point at which an electric current enters or quits the body through which it passes.

ELECTROLYSIS, -LYTE, &c., from λεKтрov, electricity, and

2ów, to loosen; the act of decomposing bodies by electricity.

ELECTRO-MAGNETISM; magnetism produced by electricity. ELECTROMETER; an instrument for ascertaining the quality and quantity of electricity in electrified bodies. ELECTROPHORUS; an instrument for producing electricity.

ELECTROSCOPE; an instrument for exhibiting the attractive and repulsive agencies of electricity.

ELEMENT, -ARY, from elementum, an element; that which cannot be resolved into two or more parts, and contains but one kind of ponderable matter.

ELLIPSE, from ¿k, deficiently, and 2ɛíπw, to leave; one of the conic sections formed by the intersection of a plane and a cone, when the plane makes a less angle with the base than that formed by the base and the side of the cone.

EMANATION, from e, out, and mano, to flow; that which issues from any substance or body.

EMPIRICAL, from ev, in, and πεipάoμal, to make trial; that which is made or is done as an experiment, independently of hypothesis or theory.

EMPYREUMATIC, from ev, in, and up, fire; having the taste or smell of burned animal or vegetable substances. ENDOSMOSE, from evdov, within, and wouòs, the act of pushing; a flowing from the outside to the inside.

EPIDERMIS, from eπì, upon, and dépμa, the skin; the exterior layer of the skin.

EQUATOR, from æquus, equal; a great circle of the sphere, equally distant from the two poles; when the sun is in this circle, the days and nights are equal in all parts of the world.

EQUILIBRIUM, from æquus, equal, and libra, a balance; the state of rest produced by forces equally balancing one another.

EQUIVALENT, from æquus, equal, and valeo, to be worth; equal in value.

ETIOLATION; the blanching of vegetables by exclusion from light.

EVAPORATION, from e, out, and vapor, vapour; the conversion of a liquid into vapour.

EXOSMOSE, from tw, without, and wouòs, the act of pushing; a flowing from inside to the outside.

EXPANSION, from expando, to open out; the enlargement or increase in the bulk of bodies, which is produced by heat.

EXPERIENCE, from experior, to attempt, to try; knowledge gained by observation.

EXPERIMENT; Something done in order to discover an uncertain or unknown effect.

EXPLOSION, from ex, out, and plaudo, to utter a sound; a sudden expansion of an elastic fluid with force, and a loud report.

EXTRANEOUS, from extra, without; foreign and contrary to the nature of a thing.

F.

FELLY; the exterior rim of a wheel, supported by the spokes. FERRUGINOUS, from ferrum, iron; of iron.

FILTER; a strainer.

FILTRATION; the process whereby liquids are strained. FLEXURE, from flecto, to bend; the act of bending; also the bend or curve of a line or figure.

FLUORINE, from fluo, to flow; an elementary principle of fluor spar, which is so called from its acting as a flux in the working of minerals.

FOCUS, -CAL, from focus, a fireplace; a point in which a number of rays of light or heat meet after being refracted or reflected.

FORMULA, a general theorem; it is called Algebraic, Logarithmic, &c., according to the branch of mathematics to which it relates.

FRICTION, from frico, to rub; the rubbing or grating of the surfaces of bodies upon one another; also the retarding force caused by this rubbing of surfaces together.

G.

GALVANISM, from Professor GALVANI; current electricity is sometimes so called.

GALVANOMETER; an instrument for measuring galvanism. GAS, -EOUS; a term first introduced by VAN HELMONT; & permanent aeriform fluid.

GELATINOUS, from gelo, to freeze; resembling jelly. GONIOMETER, from ywvía, an angle, and μérpov, a measure; an instrument for measuring angles.

GENUS, -ERIC, from genus, a whole race or kind

GEOMETRY, -ICAL, from yn, the earth, and μérpov, a measure;

the science which treats of the relative magnitudes of extended bodies.

GRAVITATION, from gravis, heavy; the abstract power which draws bodies towards each other's centres.

GRAVITY, from gravis, heavy; the natural tendency of bodies to fall towards a centre.

GRAVITY, SPECIFIC; the relative gravity of a body considered with regard to some other body, which is assumed as a standard of comparison.

H.

HALO, from aλws, a crown; a luminous circle, appearing occasionally around the heavenly bodies; but more especially about the sun and moon.

HELIOGRAPHIC, from λos, the sun, and ypάow, to write; delineated by the sun.

HELIX, from ¿λioow, to twist round; a screw or spiral. HEMISPHERE, from μovs, half, and σpaipa, a sphere; the half of a sphere formed by a plane passing through the

centre.

HERMETIC SEAL; when the neck of a glass vessel or tube is heated to the melting point, and then twisted with pincers until it be air-tight, the vessel or tube is said to be hermetically sealed, or to have received the seal of Hermes, the reputed inventor of chymistry. HETEROGENEOUS, from repos, different, and yévoç, kind; different in nature and properties.

HOMOGENEOUS, from óμòç, alike, and, yévos, kind; alike in nature and properties.

HORIZONTAL, from opiw, to bound or terminate; parallel to the horizon.

HYDRATE, from dwp, water; any uncrystallized substance which contains water in a fixed definite proportion. HYDROGEN, from dwp, water, and yɛvváw, to produce; an inflammable, colourless, and aeriform fluid; the lightest of all known substances, and one of the elements of water.

HYDRO; when prefixed to the name of a chymical substance, denotes that hydrogen enters into the composition of the substance which it signifies.

HYDROMETER, from dwp, water, and μérpov, a measure; an instrument for comparing the density and gravity of liquids with water.

HYDROSTATICS, from vdwp, water, and oraròs, standing; that

branch of Natural Philosophy which treats of the pressure and equilibrium of non-elastic fluids, and also of the weight, pressure, &c., of solids immersed in them. HYGROMETER, from vypòs, moist, and μérpov, a measure; an instrument for ascertaining accurately the quantity of moisture in the atmosphere.

HYGROSCOPE, from vypòç, moist, and σkowéw, to consider; an instrument for exhibiting approximatively the moisture of the atmosphere.

HYPERBOLA, from vrèp, excessively, and Báλw, to place; one of the conic sections formed by the intersection of a plane and a cone, when the plane makes a greater angle with the base of the cone than that formed by the base and the side of the cone.

HYPO, from vaò, under; when prefixed to a word, denotes an inferior quantity of some ingredient which enters into the composition of the substance which it signifies. HYPOTHESIS, -TICAL, from úrò, under, and ríonui, to place; a principle supposed or taken for granted in order to prove a point in question.

I.

IMMEDIATELY, from im, without, and medius, intervening; without the intervention of a second cause.

IMPINGING, from impingo, to strike against; dashing against. INCANDESCENT, from incandesco, to grow white; white or glowing with heat.

INCIDENCE, from in, upon, and cado, to fall; the direction in which one body falls on or strikes another; the angle which the moving body makes with the plane of the body struck, is called the "angle of incidence." INCREMENT, from incresco, to increase; the quantity by which anything increases or becomes greater.

INDUCTION, -IVE, from in, to, and duco, to lead; the process of reasoning, by which we are led from general to particular truths.

INDUCTION, ELECTRICAL; the effect produced by the tendency of an insulated electrified body to excite an opposite electric state in neighbouring bodies.

INDUCTOMETER; an instrument for measuring electrical induction.