Chapter 25

Per`fo*ra"tion (?), n. [Cf. F. perforation.] 1. The act of perforating, or of boring or piercing through. Bacon.

2. A hole made by boring or piercing; an aperture. "Slender perforations." Sir T. Browne.

Per"fo*ra*tive (?), a. [Cf. F. perforatif.] Having power to perforate or pierce.

Per"fo*ra`tor (?), n. [Cf. F. perforateur.] One who, or that which, perforates; esp., a cephalotome.

Per*force" (?), adv. [F. par (L. per) + force.] By force; of necessary; at any rate. Shak.

Per*force", v. t. To force; to compel. [Obs.]

Per*form" (?), v. t. [imp. & p. p. Performed (?); p. pr. & vb. n. Performing.] [OE. performen, parfourmen, parfournen, OF. parfornir, parfournir, to finish, complete; OF. & F. par (see Par) + fournir to finish, complete. The word has been influenced by form; cf. L. performare to form thoroughly. See Furnish.] 1. To carry through; to bring to completion; to achieve; to accomplish; to execute; to do.

I will cry unto God most high, unto God that performeth all things for me.

Ps. lvii. 2.

Great force to perform what they did attempt.

Sir P. Sidney.

2. To discharge; to fulfill; to act up to; as, to perform a duty; to perform a promise or a vow.

To perform your father's will.

Shak.

3. To represent; to act; to play; as in drama.

Perform a part thou hast not done before.

Shak.

Syn. -- To accomplish; do; act; transact; achieve; execute; discharge; fulfill; effect; complete; consummate. See Accomplish.

Per*form", v. i. To do, execute, or accomplish something; to acquit one's self in any business; esp., to represent sometimes by action; to act a part; to play on a musical instrument; as, the players perform poorly; the musician performs on the organ.

Per*form"a*ble (?), a. Admitting of being performed, done, or executed; practicable.

Per*form"ance (?), n. The act of performing; the carrying into execution or action; execution; achievement; accomplishment; representation by action; as, the performance of an undertaking of a duty.

Promises are not binding where the performance is impossible.

Paley.

2. That which is performed or accomplished; a thing done or carried through; an achievement; a deed; an act; a feat; esp., an action of an elaborate or public character. "Her walking and other actual performances." Shak. "His musical performances." Macaulay.

Syn. -- Completion; consummation; execution; accomplishment; achievement; production; work; act; action; deed; exploit; feat.

Per*form"er (?), n. One who performs, accomplishes, or fulfills; as, a good promiser, but a bad performer; especially, one who shows skill and training in any art; as, a performer of the drama; a performer on the harp.

Per"fri*cate (?), v. t. [L. perfricatus, p. p. of perfricare.] To rub over. Bailey.

Per*fu"ma*to*ry (?), a. Emitting perfume; perfuming. [R.] Sir E. Leigh.

Per*fume" (?), v. t. [imp. & p. p. Perfumed (?); p. pr. & vb. n. Perfuming.] [F. parfumer (cf. Sp. perfumar); par (see Par) + fumer to smoke, L. fumare, fr. fumus smoke. See Fume.] To fill or impregnate with a perfume; to scent.

And Carmel's flowery top perfumes the skies.

Pope.

Per"fume (?), n. [F. parfum; cf. Sp. perfume. See Perfume, v.] 1. The scent, odor, or odoriferous particles emitted from a sweet-smelling substance; a pleasant odor; fragrance; aroma.

No rich perfumes refresh the fruitful field.

Pope.

2. A substance that emits an agreeable odor.

And thou shalt make it a perfume.

Ex. xxx. 35.

Per*fum"er (?), n. 1. One who, oe that which, perfumes.

2. One whose trade is to make or sell perfumes.

Per*fum"er*y (?), n. 1. Perfumes, in general.

2. [Cf. F. parfumerie.] The art of preparing perfumes.

Per*func"to*ri*ly (?), adv. In a perfunctory manner; formally; carelessly. Boyle.

Per*func"to*ri*ness, n. The quality or state of being perfunctory.

Per*func"to*ry (?), a. [L. perfunctorius, fr. perfunctus dispatched, p. p. of perfungi to discharge, dispatch; per (see Per) + fungi to perform. See Function.] 1. Done merely to get rid of a duty; performed mechanically and as a thing of rote; done in a careless and superficial manner; characterized by indifference; as, perfunctory admonitions. Macaulay.

2. Hence: Mechanical; indifferent; listless; careless. "Perfunctory in his devotions." Sharp.

Per*func"tu*rate (?), v. t. To perform in a perfunctory manner; to do negligently. [R.]

Per*fuse" (?), v. t. [imp. & p. p. Perfused (?); p. pr. & vb. n. Perfusing.] [L. perfusus, p. p. of perfundere to pour over; per + fundere to pour.] To suffuse; to fill full or to excess. Harvey.

Per*fu"sion (?), n. [L. perfusio.] The act of perfusing.

Per*fu"sive (?), a. Of a nature to flow over, or to spread through.

{ Per`ga*me"no*us (?), Per`ga*men*ta"ceous (?), } a. [L. pergamena parchment. See Parchment.] Like parchment.

Per*haps" (?), adv. [Per + hap chance.] By chance; peradventure; perchance; it may be.

And pray God, if perhaps the thought of thine heart may be forgiven thee.

Acts viii. 22.

Per"i- (?). [Gr. &?;, prep.] A prefix used to signify around, by, near, over, beyond, or to give an intensive sense; as, perimeter, the measure around; perigee, point near the earth; periergy, work beyond what is needed; perispherical, quite spherical.

Pe"ri (?), n.; pl. Peris (#). [Per. per a female genus, a fairy.] (Persian Myth.) An imaginary being, male or female, like an elf or fairy, represented as a descendant of fallen angels, excluded from paradise till penance is accomplished. Moore.

<! p. 1066 !>

Per`i*a"gua (?), n. See Pirogue.

Per"i*anth (?), n. [Pref. peri- + Gr. &?; flower: cf. F. pÈrianthe.] (Bot.) (a) The leaves of a flower generally, especially when the calyx and corolla are not readily distinguished. (b) A saclike involucre which incloses the young fruit in most hepatic mosses. See Illust. of Hepatica.

||Per`i*an"thi*um (?), n. [NL.] (Bot.) The perianth.

Per"i*apt (?), n. [Gr. &?;, fr. &?; hung about, &?; to hang about; &?; about + &?; to tie: cf. F. pÈriapte.] A charm worn as a protection against disease or mischief; an amulet. Coleridge.

Now help, ye charming spells and periapts.

Shak.

Per`i*as"tral (?), a. Among or around the stars. "Comets in periastral passage." R. A. Proctor.

Per`i*as"tron (?), n. [NL., fr. Gr. &?; about + &?; a star.] (Astron.) That point, in the real or apparent orbit of one star revolving around another, at which the former is nearest to the latter.

Per"i*au"ger (?), n. See Pirogue. W. Irving.

Per"i*blast (?), a. [Gr. &?; to grow around. See Peri-, and -blast.] (Biol.) The protoplasmic matter which surrounds the entoblast, or cell nucleus, and undergoes segmentation. -- Per`i*blas"tic, a.

Per"i*blem (?), n. [Pref. peri- + root of Gr. &?; to sprout.] (Bot.) Nascent cortex, or immature cellular bark.

||Pe*rib"o*los (?), n. [Nl., fr. Gr. &?;, fr. &?;, adj., going round, ||fr. &?; to throw round; cf. L. peribolus.] In ancient architecture, ||an inclosed court, esp., one surrounding a temple.

Per`i*bran"chi*al (?), a. (Anat.) Surrounding the branchiÊ; as, a peribranchial cavity.

Per`i*bran"chi*al (?), a. (Anat.) Around the bronchi or bronchial tubes; as, the peribronchial lymphatics.

||Per`i*cam"bi*um (?), n. [NL. See Peri-, and Cambium.] (Biol.) A layer ||of thin-walled young cells in a growing stem, in which layer certain ||new vessels originate.

{ Per`i*car"di*ac (?), Per`i*car"di*al (?), } a. (Anat.) Of or pertaining to pericardium; situated around the heart.

Pericardial fluid (Physiol.), a serous fluid of a pale yellow color contained in the pericardium.

Per`i*car"di*an (?), a. Pericardiac.

Per`i*car"dic (?), a. Pericardiac.

||Per`i*car*di"tus (?), n. [NL. See Pericardium, and -itis.] (Med.) ||Inflammation of the pericardium. Dunglison.

Per`i*car"di*um (?), n. [NL., fr. Gr. &?;, fr. &?; about or near the heart; &?; about + &?; heart.] (Anat.) The double baglike fold of serous membrane which incloses the heart.

The inner layer is closely adherent to the outer surface of the heart, and is called the cardiac pericardium. The outer layer loosely incloses the heart and the adherent inner layer, and is called the parietal pericardium. At the base of the heart the two layers are continuous, and form a narrow closed cavity filled with fluid, in which the pulsations of the heart cause little friction.

Per"i*carp (?), n. [Gr. &?;; &?; around + &?; fruit: cf. F. pÈricarpe.] (Bot.) The ripened ovary; the walls of the fruit. See Illusts. of Capsule, Drupe, and Legume.

{ Per`i*car"pi*al (?), Per`i*car"pic (?) }, a. (Bot.) Of or pertaining to a pericarp.

Per`i*cel"lu*lar (?), a. (Anat.) Surrounding a cell; as, the pericellular lymph spaces surrounding ganglion cells.

Per"i*chÊth (?), n. [See PerichÊtium.] (Bot.) The leafy involucre surrounding the fruit stalk of mosses; perichÊtium; perichete.

Per`i*chÊ"ti*al (?), a. (Bot.) Of or pertaining to the perichÊth.

||Per`i*chÊ"ti*um (?), n.; pl. PerichÊtia (#). [NL., fr. Gr. &?; about ||+ &?; flowing hair, foliage.] (Bot.) Same as PerichÊth.

Per`i*chÊ"tous (?), a. [See PerichÊtium.] (Zoˆl.) Surrounded by setÊ; -- said of certain earthworms (genus PerichÊtus).

Per"i*chete (?), n. Same as PerichÊth.

Per`i*chon"dri*al (?), a. (Anat.) Of or pertaining to the perichondrium; situated around cartilage.

||Per`i*chon*dri"tis (?), n. [NL. See Perichondrium, and -itis.] (Med.) ||Inflammation of the perichondrium.

||Per`i*chon"dri*um (?), n. [NL., fr. Gr. &?; around + &?; cartilage.] ||(Anat.) The membrane of fibrous connective tissue which closely ||invests cartilage, except where covering articular surfaces.

Per`i*chor"dal (?), a. Around the notochord; as, a perichordal column. See Epichordal.

{ Per"i*clase (?), Per`i*cla"site (?), } n. [Pref. peri- + Gr. &?; to break.] (Min.) A grayish or dark green mineral, consisting essentially of magnesia (magnesium oxide), occurring in granular forms or in isometric crystals.

||Per`i*clin"i*um (?), n.; pl. Periclinia (#). [NL., fr. Gr. &?; around ||+ &?; a bed.] (Bot.) The involucre which surrounds the common ||receptacle in composite flowers.

Pe*ric"li*tate (?), v. t. [L. periclitatus, p. p. of periclitari, fr. periculum.] To endanger. [Obs.]

Periclitating, pardi! the whole family.

Sterne.

Pe*ric`li*ta"tion (?), n. [L. periclitatio: cf. F. pÈriclitation.] 1. Trial; experiment. [Obs.]

2. The state of being in peril. [Obs.]

||Pe*ric"o*pe (?), n. [L., section of a book, Gr. &?;; &?; around + &?; ||to cut.] A selection or extract from a book; especially (Theol.), a ||selection from the Bible, appointed to be read in the churches or ||used as a text for a sermon.

Per`i*cra"ni*al (?), a. (Anat.) Of or pertaining to the pericranium.

Per`i*cra"ni*um (?), n. [NL.] (Anat.) The periosteum which covers the cranium externally; the region around the cranium.

Pe*ric"u*lous (?), a. [L. periculosus. See Perilous.] Dangerous; full of peril. [Obs.]

||Pe*ric"u*lum (?), n.; pl. Pericula (#). [L.] (Rom. & O.Eng. Law) 1. ||Danger; risk.

2. In a narrower, judicial sense: Accident or casus, as distinguished from dolus and culpa, and hence relieving one from the duty of performing an obligation.

Per"i*derm (?), n. 1. (Bot.) The outer layer of bark.

2. (Zoˆl.) The hard outer covering of hydroids and other marine animals; the perisarc.

||Per`i*di*as"to*le (?), n. (Physiol.) The almost inappreciable time ||which elapses between the systole and the diastole of the heart.

||Pe*rid"i*um (?), n.; pl. Peridia (#). [NL., fr. Gr. &?; about + &?;, ||a dim. ending.] (Bot.) The envelope or coat of certain fungi, such as ||the puffballs and earthstars.

Per"i*dot (?), n. [F. pÈridot.] (Min.) Chrysolite.

Per"i*do*tite (?), n. [Cf. F. pÈridotite.] (Min.) An eruptive rock characterized by the presence of chrysolite (peridot). It also usually contains pyroxene, enstatite, chromite, etc. It is often altered to serpentine.

The chief diamond deposits in South Africa occur in a more or less altered peridotite.

Per"i*drome (?), n. [Gr. &?;, fr. &?; running around, fr. &?; to run round; &?; round + &?; to run: cf. F. pÈridrome.] (ArchÊol.) The space between the columns and the wall of the cella, in a Greek or a Roman temple.

Per`i*e"cians (?), n. pl. See Periúcians.

||Per`i*en"te*ron (?), n. [NL. See Peri-, and Enteron.] (Anat.) The ||primitive perivisceral cavity.

Per"i*er`gy (?), n. [Gr. &?;, fr. &?; overcareful; &?; about, beyond + &?; work.] 1. Excessive care or diligence. [Obs.]

2. (Rhet.) A bombastic or labored style. [R.]

Per`i*gan`gli*on"ic (?), a. (Anat.) Surrounding a ganglion; as, the periganglionic glands of the frog.

Per`i*gas"tric (?), a. (Zoˆl.) Surrounding the stomach; -- applied to the body cavity of Bryozoa and various other Invertebrata.

Per`i*ge"an (?), a. Pertaining to the perigee.

Perigean tides, those spring tides which occur soon after the moon passes her perigee.

{ Per"i*gee (?), Per`i*ge"um (?), } n. [NL. perigeum, fr. Gr. &?; about, near + &?; the earth: cf. F. pÈrigÈe.] (Astron.) That point in the orbit of the moon which is nearest to the earth; -- opposed to apogee. It is sometimes, but rarely, used of the nearest points of other orbits, as of a comet, a planet, etc. Called also epigee, epigeum.

Per`i*gen"e*sis (?), n. (Biol.) A theory which explains inheritance by the transmission of the type of growth force possessed by one generation to another.

Per`i*gen"e*tic (?), a. (Biol.) Of or pertaining to perigenesis.

Per"i*gone (?), n. [Pref. peri- + Gr. &?; productive organs.] 1. (Bot.) (a) Any organ inclosing the essential organs of a flower; a perianth. (b) In mosses, the involucral bracts of a male flower.

2. (Zoˆl.) A sac which surrounds the generative bodies in the gonophore of a hydroid.

||Per`i*go"ni*um (?), n.; pl. Perigonia (#). [NL.] Same as Perigone.

Per"i*gord pie` (?). [From PÈrigord, a former province of France.] A pie made of truffles, much esteemed by epicures.

Per"i*graph (?), n. [Gr. &?; outline; &?; round, about + &?; to write.] A careless or inaccurate delineation of anything. [R.]

||Per`i*gyn"i*um (?), n.; pl. Perigynia (#). [NL. See Perigynous.] ||(Bot.) Some unusual appendage about the pistil, as the bottle-shaped ||body in the sedges, and the bristles or scales in some other genera ||of the Sedge family, or CyperaceÊ.

Pe*rig"y*nous (?), a. [Pref. peri- + Gr. &?; woman.] (Bot.) Having the ovary free, but the petals and stamens borne on the calyx; -- said of flower such as that of the cherry or peach.

{ Per`i*hel"ion (?), Per`i*he"li*um (?), } n.; pl. Perihelia (#). [NL., fr. Gr. &?; about, near + &?; the sun.] (Astron.) That point of the orbit of a planet or comet which is nearest to the sun; -- opposed to aphelion.

Per"il (?), n. [F. pÈril, fr. L. periculum, periclum, akin to peritus experienced, skilled, and E. fare. See Fare, and cf. Experience.] Danger; risk; hazard; jeopardy; exposure of person or property to injury, loss, or destruction.

In perils of waters, in perils of robbers.

2 Cor. xi. 26.

Adventure hard With peril great achieved.

Milton.

At, or On, one's peril, with risk or danger to one; at the hazard of. "On thy soul's peril." Shak.

Syn. -- Hazard; risk; jeopardy. See Danger.

Per"il, v. t. [imp. & p. p. Periled (?) or Perilled; p. pr. & vb. n. Periling or Perilling.] To expose to danger; to hazard; to risk; as, to peril one's life.

Per"il (?), v. i. To be in danger. [Obs.] Milton.

||Pe*ril"la (?), n. [Etymol. uncertain.] (Bot.) A genus of labiate ||herbs, of which one species (Perilla ocimoides, or P. Nankinensis) is ||often cultivated for its purple or variegated foliage.

Per"il*ous (?), a. [OF. perillous, perilleus, F. pÈrilleux, L. periculosus. See Peril.] [Written also perillous.] 1. Full of, attended with, or involving, peril; dangerous; hazardous; as, a perilous undertaking.

Infamous hills, and sandy, perilous wilds.

Milton.

2. Daring; reckless; dangerous. [Obs.] Latimer.

For I am perilous with knife in hand.

Chaucer.

-- Per"il*ous*ly, adv. -- Per"il*ous*ness, n.

Per"i*lymph (?), n. (Anat.) The fluid which surrounds the membranous labyrinth of the internal ear, and separates it from the walls of the chambers in which the labyrinth lies.

Per`i*lym*phan"gi*al (?), a. (Anat.) Around, or at the side of, a lymphatic vessel.

Per`i*lym*phat"ic (?), a. (Anat.) (a) Pertaining to, or containing, perilymph. (b) Perilymphangial.

Per*im"e*ter (?), n. [Gr. &?;; &?; around + &?; measure: cf. F. pÈrimËtre.] 1. (Geom.) The outer boundary of a body or figure, or the sum of all the sides.

2. An instrument for determining the extent and shape of the field of vision.

{ Per`i*met"ric (?), Per`i*met"ric*al (?), } a. Of or pertaining to the perimeter, or to perimetry; as, a perimetric chart of the eye.

Per*im"e*try (?), n. The art of using the perimeter; measurement of the field of vision.

Per"i*morph (?), n. [Pref. peri- + Gr. &?; form.] (Min.) A crystal of one species inclosing one of another species. See Endomorph.

Per`i*my"sial (?), a. (Anat.) (a) Surrounding a muscle or muscles. (b) Of or pertaining to the perimysium.

||Per`i*my"si*um (?), n. [NL., fr. Gr. &?; about + &?; muscle.] (Anat.) ||The connective tissue sheath which surrounds a muscle, and sends ||partitions inwards between the bundles of muscular fibers.

||Per`i*nÊ"um (?), n. See Perineum.

Per`i*ne"al (?), a. (Anat.) Of or pertaining to the perineum.

Per`i*ne"o*plas`ty (?), n. [Perineum + -plasty.] (Med.) The act or process of restoring an injured perineum.

Per`i*ne*or"rha*phy (?), n. [Perineum + Gr. &?; to sew.] (Med.) The operation of sewing up a ruptured perineum.

||Per`i*ne*phri"tis (?), n. [NL. See Peri-, and Nephritis.] (Med.) ||Inflammation of the cellular tissue around the kidney. -- ||Per`i*ne*phrit"ic, a.

||Per`i*ne"um (?), n. [NL., fr. Gr. &?;, &?;.] (Anat.) The region which ||is included within the outlet of the pelvis, and is traversed by the ||urinogenital canal and the rectum.

Per`i*neu"ri*al (?), a. (Anat.) Surrounding nerves or nerve fibers; of or pertaining to the perineurium.

||Per`i*neu"ri*um (?), n. [NL., fr. Gr. &?; about + &?; a nerve.] ||(Anat.) The connective tissue sheath which surrounds a bundle of ||nerve fibers. See Epineurium, and Neurilemma.

Per`i*nu"cle*ar (?), a. (Biol.) Of or pertaining to a nucleus; situated around a nucleus; as, the perinuclear protoplasm.

Pe"ri*od (?), n. [L. periodus, Gr. &?; a going round, a way round, a circumference, a period of time; &?; round, about + &?; a way: cf. F. pÈriode.] 1. A portion of time as limited and determined by some recurring phenomenon, as by the completion of a revolution of one of the heavenly bodies; a division of time, as a series of years, months, or days, in which something is completed, and ready to recommence and go on in the same order; as, the period of the sun, or the earth, or a comet.

2. Hence: A stated and recurring interval of time; more generally, an interval of time specified or left indefinite; a certain series of years, months, days, or the like; a time; a cycle; an age; an epoch; as, the period of the Roman republic.

How by art to make plants more lasting than their ordinary period.

Bacon.

3. (Geol.) One of the great divisions of geological time; as, the Tertiary period; the Glacial period. See the Chart of Geology.

4. The termination or completion of a revolution, cycle, series of events, single event, or act; hence, a limit; a bound; an end; a conclusion. Bacon.

So spake the archangel Michael; then paused, As at the world's great period.

Milton.

Evils which shall never end till eternity hath a period.

Jer. Taylor.

This is the period of my ambition.

Shak.

5. (Rhet.) A complete sentence, from one full stop to another; esp., a well-proportioned, harmonious sentence. "Devolved his rounded periods." Tennyson.

Periods are beautiful when they are not too long.

B. Johnson.

The period, according to Heyse, is a compound sentence consisting of a protasis and apodosis; according to Becker, it is the appropriate form for the coˆrdinate propositions related by antithesis or causality. Gibbs.

6. (Print.) The punctuation point [.] that marks the end of a complete sentence, or of an abbreviated word.

7. (Math.) One of several similar sets of figures or terms usually marked by points or commas placed at regular intervals, as in numeration, in the extraction of roots, and in circulating decimals.

<! p. 1067 !>

8. (Med.) The time of the exacerbation and remission of a disease, or of the paroxysm and intermission.

9. (Mus.) A complete musical sentence.

The period, the present or current time, as distinguished from all other times.

Syn. -- Time; date; epoch; era; age; duration; limit; bound; end; conclusion; determination.

Pe"ri*od (?), v. t. To put an end to. [Obs.] Shak.

Pe"ri*od, v. i. To come to a period; to conclude. [Obs.] "You may period upon this, that," etc. Felthman.

Per*i"o*date (?), n. (Chem.) A salt of periodic acid.

Per`i*od"ic (?), a. [Pref. per- + iodic.] (Chem.) Pertaining to, derived from, or designating, the highest oxygen acid (HIO&?;) of iodine.

{ Pe`ri*od"ic (?), Pe`ri*od"ic*al (?), } a. [L. periodicus, Gr. &?;: cf. F. pÈriodique.] 1. Of or pertaining to a period or periods, or to division by periods.

The periodicaltimes of all the satellites.

Sir J. Herschel.

2. Performed in a period, or regular revolution; proceeding in a series of successive circuits; as, the periodical motion of the planets round the sun.

3. Happening, by revolution, at a stated time; returning regularly, after a certain period of time; acting, happening, or appearing, at fixed intervals; recurring; as, periodical epidemics.

The periodic return of a plant's flowering.

Henslow.

To influence opinion through the periodical press.

Courthope.

4. (Rhet.) Of or pertaining to a period; constituting a complete sentence.

Periodic comet (Astron.), a comet that moves about the sun in an elliptic orbit; a comet that has been seen at two of its approaches to the sun. -- Periodic function (Math.), a function whose values recur at fixed intervals as the variable uniformly increases. The trigonomertic functions, as sin x, tan x, etc., are periodic functions. Exponential functions are also periodic, having an imaginary period, and the elliptic functions have not only a real but an imaginary period, and are hence called doubly periodic. -- Periodic law (Chem.), the generalization that the properties of the chemical elements are periodic functions of their atomic wieghts. "In other words, if the elements are grouped in the order of their atomic weights, it will be found that nearly the same properties recur periodically throughout the entire series." The following tabular arrangement of the atomic weights shows the regular recurrence of groups (under I., II., III., IV., etc.), each consisting of members of the same natural family. The gaps in the table indicate the probable existence of unknown elements.

A similar relation had been enunciated in a crude way by Newlands; but the law in its effective form was developed and elaborated by Mendelejeff, whence it is sometimes called Mendelejeff's law. Important extensions of it were also made by L. Meyer. By this means Mendelejeff predicted with remarkable accuracy the hypothetical elements ekaboron, ekaluminium, and ekasilicon, afterwards discovered and named respectively scandium, gallium, and germanium.

-- Periodic star (Astron.), a variable star whose changes of brightness recur at fixed periods. -- Periodic time of a heavenly body (Astron.), the time of a complete revolution of the body about the sun, or of a satellite about its primary.

Pe`ri*od"ic*al, n. A magazine or other publication which appears at stated or regular intervals.

Pe`ri*od"ic*al*ist, n. One who publishes, or writes for, a periodical.

Pe`ri*od"ic*al*ly, adv. In a periodical manner.

Pe`ri*od"ic*al*ness, n. Periodicity.