the members of the family who had committed this offence against religion, as it was an indirect way of attacking Pericles and driving him into exile. The Athenians retorted by urging the Lacedæmonians to cleanse themselves from the guilt incurred by the death of Pausanias.

Pericles lived to direct the Peloponnesian war for two years. His policy was to induce the Athenians to consider Attica merely as a post, to be held or resigned as occasion required. In the speech which he made before war was declared, as it is recorded by Thucydides, he impressed the Athenians with these opinions, representing the superiority of their navy and the importance of avoiding conflicts in the field, which, if successful, could only bring temporary advantage-if the contrary, would be irretrievable.

At the end of the first campaign, Pericles delivered an oration upon those who had fallen in the war. This speech, the full transfusion of which into a modern language is an impossibility, exhibits a more complete view of the intellectual power and moral character of Pericles than all that the historian and biographer have said of him. The plague of Athens followed, and while it damped the activity of the Athenians, it increased their impatience of war. In spite of another harangue, in which he represented how absurd it would be to allow such an event as a pestilence to interfere with well-laid plans, he was brought to trial and fined, but his influence

REPIKALT

Bust of Pericles.

returned when the panic was over. In the third year of the war, having lost his two legitimate sons, his sister, and many of his best friends, by the plague, he fell ill, and after a lingering sickness, died.

The connection of Pericles with Aspasia is a part of his private life which is not quite clear. Aspasia was a foreigner who came to Athens, and Pericles lived with her after divorcing his wife. He appears to have been much attached to her, and probably, as she was a woman of talent and of great personal charms, she had some influence over him.

PERICRA'NIUM is the tough fibrous membrane which covers the bones of the skull, and bears the same relation to them which the periosteum does to the bones of the rest of the skeleton. [BONE.]

PERIGEE, the point of the moon's orbit in which she is nearest to the earth.

PE'RIGORD, a former province of France, included in the military government of Guienne, now forms the department of DORDOGNE, and part of GIRONDE. Its capital was Périgueux.

PERIGUEUX. [DORDOGNE.]

PERIHE'LION, the point of the earth's orbit in which it is nearest to the sun. [APHELION.]

PERIM, a small and barren islet, about 3 miles long by 2 broad, situated at the mouth of the Red Sea, about 1 mile from the Arabian, and 13 miles from the African coast. It is destitute of fresh water, and owes all its importance to its commanding the entrance of the Red Sea. It was first occupied by the British in 1799; abandoned in 1801; and again taken possession of in February, 1857, as a check to the supposed designs of France in promoting the construction of the Suez Canal. It has been strongly fortified, and a lighthouse erected for the guidance of navigators. On the south-west side lies an excellent harbour, 6 furlongs broad, which could accommodate a fleet of forty men-of-war.

PERIMETER, the circuit or bounding lines of a plane figure; a term usually applied to rectilinear figures only, but without any particular reason for the restriction.

PERIODICAL, a journal of criticism, art, literature, religion, and belles lettres, published at regular intervals. The first which appeared in England was the Philosophical Transactions of the Royal Society, 1665. In 1692 appeared the Gentlemen's Journal, the first English magazine; and in 1749, the Monthly Review, the first English periodical devoted to criticism. The following dates may be useful:

Gentlemen's Magazine, .
Edinburgh Review,
Quarterly Review,

Blackwood's Magazine,
Westminster Review,
The Athenæum,
Frazer's Magazine,
North British Review,

Saturday Review,.
Cornhill Magazine,

Nineteenth Century,.

started in 1731

PERIODS OF REVOLUTION. By a period we mean a definite portion of time, beginning from a given epoch, which, being repeated again and again, will serve to divide all time subsequent to the epoch (or precedent, if the repetitions be also carried backwards from the epoch) into equal parts, for the purposes of common reckoning and historical chronology.

Periods may be divided into natural and artificial: the former immediately suggested by some recurrence of astronomical phenomena; the latter arbitrarily chosen.

When one period is contained an exact number of times in another, each recommencement of the larger one is also a recommencement of the smaller one: thus the day being exactly twenty-four hours, if any one day begin at the beginning of an hour, all days will do the same. But if the smaller period be not a measure of the larger, a longer period may be imagined, which may be called a cycle, consisting of the interval between the two nearest moments at which the smaller and larger periods begin together. Thus a week of seven days and a month of thirty days give a cycle of seven months or thirty weeks, these two periods being equal.

The periods in which all others are expressed is the day, which is not, as many suppose, the simple time of the revolution of the earth, but the average time between

noon and noon. To distinguish it from other days it is called the mean solar day.

The year, or the time between two vernal equinoxes, is not a uniform period, nor does the average of one long period give precisely the same as that of another. For chronological purposes, however, it is useless to take account of this variation, and 365-2422414 days, the year of astronomers in our day, may be considered as more than sufficiently exact for any time. In fact the year is made to consist, in the long run, of 365-2425 days in the Gregorian calendar.

An Era means either the commencement of an indefinite reckoning, or of a succession of periods. In the following list the figures following the years refer to months and days: thus A.D. 729-6-13 would stand for the 13th day of June, A.D. 729. We do not mean to say that the events in the following list did take place in the years, far less in the months, or on the days, which are set down; but only that those who used them as eras took them as having happened in those years, months, and days. Thus the death of Alexander, according to Clinton, took place in B.C. 323, which is most likely to be right; but if those who afterwards made an era of this death reckoned from the 12th of November B.C. 324, that day is the era, whether the event happened

then or not:

B.C. 49

B.C. 38.1.1 B.C. 30.1.1

A.D. 8

A.D. 38

A.D. 312.9.1 A.D. 552.7.9 A.D. 622.7.16 A.D. 632.6.16 A.D. 1582 A.D. 1752

Before the change of style in 1752, and from the fourteenth century to that time, the legal and ecclesiastical year began on the 25th of March, though it was very common in writings, &c., to begin it on the 1st of January. Hence January, February, and twenty-four days of March, were in one year, according to lawyers, &c.; and in another according to others. Thus the Revolution, so called, of 1688, took place in the February of that legal year, or, as we should now say, February,

1. The Cycle of the Sun is a period of 28 years, compounded of 7 and 4, the number of days in a week, and the number of years in the interval of two leapyears. This, in the old style, makes the Sundays return to the same days of the year.

2. The Cycle of the Moon is that of 19 years, which is very nearly 235 complete lunations, as follows:-The 235 mean lunations of 29-53059 days each make 6939-69 days, while 19 years of 365 days each give 6935 days, and allowing 4 days for leap years, 6939-75 days. Hence 235 lunations fall short of 19 Julian years by 06 of a day, or one day in about 317 years. Hence during a period of 300 years, and as far as the mean place of the moon is concerned, the new and full moons of the cycle of 19 years would fall on the same days.

3. The Indiction was an edict of the Roman emperors, fixing the tribute, and as one such edict was supposed to have appeared every fifteen years, years were naturally reckoned according to their distance from the year of Indiction. There is doubt about the first origin of indictions, about their meaning and their earliest date: all we have here to do with is the fact, that from Athanasius downwards, they were more or less employed by ecclesiastical writers in describing epochs. The popes afterwards adopted this mode of dating, and the common Indiction found in chronological tables begins so that 313 is the first year of the first cycle of Indiction, each cycle containing 15 years. At this rate A.D. 1 was the fourth year of an imaginary preceding indiction, and the remainder of three more than the date of any year divided by 15 will give its position in its cycle of Indiction. Thus 1239, increased by 3 and divided by 15, gives the remainder 12, or 1239 is the twelfth year of a cycle of Indiction.

4. The Paschal Cycle is one compounded of 28 and 19 years, or 532 years, during which time the cycles of the sun and of 19 years run through all their combinations, and recommence them again. According to the old system then, this is the cycle of Easter days, which begin again in the same order when it is finished.

A.D.

1 was the second year of the first paschal cycle, being also 2 of the cycle of 19 years, and 10 of its solar cycle. The paschal cycle of the Gregorian Calendar would be 53,200 years.

5. The Julian Period was imagined by Julius Scaliger, and is a combination of the solar cycle, the cycle of 19 years, and that of Indictions. Now 28 + 1915 gives 7980 years, which is the length of the period in question. It was made to begin at a year B.C., which was the first year of each cycle, namely, B.C. 4713 years. Hence, subtract any year B.C. from 4714, or add any year A.D. to 4713, and you have the year of the Julian period answering to the date used. The advantage (if it be one) of this period is, that by dividing the year in it by 28, 19, and 15, the remainders show the years of the different cycles belonging to the

Julian date used, remembering when the remainder is nothing to substitute the divisor instead.

PERICECI (go), an old astronomical term for those who have the same latitude, but opposite longitudes. PERIOSTEUM. [BONE.]

PERIPATETICS (Gr. #iginativ, 'to walk about'), a school of ancient philosophers, founded by Aristotle, who instructed his scholars in a giraros, or covered walk, of the Lyceum at Athens. His doctrines were afterwards taught by Theophrastus, Aristoxenus, Strato, and Eudemus, Glycon and Hieronymus; but none of these, or of their successors, ever attained a wide reputation or permanent influence.

PERIPHERY, the Greek word for circumference; a term applied both to rectilinear and curvilinear figures. PERIPLUS (Gr. #ig, around,' and λt, 'I sail'), a record or narration of a voyage of circumnavigation. The title is almost wholly confined to some fragments of voyages handed down to us from the classic writers, as the Periplus of Hanno, which refers to a voyage along the western coast of Africa; the Periplus of Scylax, describing the coasts of Europe and Asia; and the Periplus of Arrian, which relates to the Euxine and the Persian Gulf. PERIPNEUMONY (Peripneumonia). [LUNGS, DISEASES OF THE.]

PERIPTERAL. [CIVIL ARCHITECTURE.]

PERI'SCII (whose shadows move round'). In those latitudes which are high enough to have the sun for twenty-four hours together, the shadows make complete revolutions, whence the inhabitants may be called Periscii (Περίσκιοι).

PERISTALTIC (Gr. #igiadrinos, 'compressing'), in Medicine, a term applied to the peculiar vermicular or worm-like motion of the intestines, by which their contents are regularly discharged. This act of defocation occurs, in most cases, once or twice in twenty-four hours, and any marked irregularity is indicative of a derangement of the system.

PERISTO MIANS, the name for a family of fluviatile operculated Gastropods, breathing water, consisting of the genera Valvata, Paludina, and Ampullaria. The genus Valvata has hitherto been found only in Europe and North America. The genus Paludina is widely spread, occurring in Europe, Asia, Africa, and America. Example, Paludina vivipara (Helix vivipara, Linn.), common in the rivers and ponds in England, France, Germany, &c. The genus Ampullaria is found in the rivers and lakes of warm climates only.

PERISTO'MIUM, in mosses, the ring or fringe of bristles or teeth which are seated immediately below the operculum, and close up the orifice of the seed-vessel. This organ is highly hygrometrical, and is supposed to assist in dispersing the spores or seed-like particles by which such plants are propagated.

PERISTYLE (Gr. wigs, and rudos, 'a column'), a court or interior area, surrounded with columns on three sides.

PERITONE'UM, the membrane by which the walls of the abdominal cavity are lined, and all the abdominal organs covered. The name is also sometimes applied to the cavity itself. The arrangement of the peritoneum is similar to that of other serous membranes. It is the peritoneum which gives to all the organs within the abdomen their peculiar shining surfaces, and which, by its duplicatures, forms the mesentery, omentum, and other folds, by which those organs are attached to each other and to the wall of the abdomen, and through which their vessels pass.

PERITONITIS, an inflammation of the peritoneum.

It may exist either as an acute or as a chronic disease. The chief symptons of the acute form are pain, swelling, and tenderness of the abdomen, accompanied with fever and a frequent, small, and hard pulse. The pain in peritonitis is usually much more severe than that of any other inflammatory disease of the intestines or other abdominal organs. It is acute and cutting, and sometimes occurs in paroxysms; it is generally diffused, but occasionally it is almost confined to a single part of the abdomen; but its most distinguishing character is that it is greatly increased by pressure, so that in a severe case the patient cannot support so much as the weight of the bed-clothes, but lies on his back with his knees drawn up, and breathes quickly and lightly, moving the diaphragm as little as possible, so as to avoid the pain which its pressure would excite in the inflamed parts. The bowels in cases of peritonitis are usually, but by no means constantly, constipated; commonly also there are present nausea, vomiting, and hiccup, and almost always excessive thirst and prostration of strength. If not checked in its course, acute peritonitis usually terminates fatally in from five to ten days; the patient becoming more and more depressed, and all the symptoms regularly increasing till within a short time of death, when the pain commonly ceases, and a deceptive improvement in many of the other signs of the disease takes place.

The usual morbid effects of peritonitis are the effusion of serum with lymph or pus into the cavity of the abdomen, and adhesions of the opposite surfaces of the several organs within it.

The causes of peritonitis are-exposure to cold, and injuries of the peritoneum, as by tumours developed within the abdomen; by the obstructions which occur in strangulated hernia, and intussusception, of which it is a constant consequence; by the spreading of disease from the adjacent viscera; by heavy blows and falls on the abdomen; by penetrating wounds inflicted in operations for hernia or in other circumstances; by the passage of foreign bodies into the cavity of the abdomen; and especially by the ulcerative perforation or accidental rupture of any of the organs contained within it, and the escape of their contents, circumstances which are productive of the most certainly and rapidly fatal form of the disease.

The appropriate treatment of peritonitis consists in the early employment of copious bleeding, and the administration of calomel and opium.

Acute peritonitis sometimes, after fifteen or twenty days' continuance, assumes a chronic form; or the inflammation may from its commencement be of slow progress. In either case the symptoms are usually very obscure; the pain being but slight, or discoverable only by considerable pressure, and the swelling or tension of the abdomen occurring only at a late period of the disease. In the treatment of chronic peritonitis, local bleedings should be frequently employed, and blisters, or other counter-irritants applied over the abdomen. The diet should be light and nutritious, and, as often as they seem necessary, mild purgatives may be administered. Frictions of ointments containing mercury or iodine are also useful, and iodine should be administered internally when the patient is of a scrofulous constitution.

PERIWINKLE, (Fr. pervenche) the vernacular name for the well-known species of Turbo hawked about the streets and sold in great quantities, especially to the poorer classes. In very hot weather and the decline of the year they are unwholesome, especially if there be any predisposition to disordered functions of the abdominal

PERIWINKLE (Fr. pervenche), the popular name for Vinea, a genus of Apocynaceous plants, comprising but few species. Several varieties are well adapted for ornamenting artificial rockwork.

PERJURY (from the Latin perjurium), by the common law of England, is the offence of falsely swearing to facts in a judicial proceeding. To constitute this offence the party must have been lawfully sworn to speak the truth by some court, judge, or officer having competent authority to administer an oath; and, under the oath so administered, he must wilfully assert a falsehood in a judicial proceeding respecting some fact which is material to the subject of inquiry in that proceeding. In a legal sense, therefore, the term has a much narrower import than it has in its popular acceptation. A person may commit perjury by swearing that he believes a fact to be true which he knows to be false. It is immaterial whether the false statement has received credit or not, or whether any injury has been sustained by an individual in consequence of it. The offence of perjury is a Misdemeanor. Perjury must be proved by more than the mere contradictory oath of the prosecutor; he must be corroborated by some independent witness.

A defendant in equity is guilty of perjury by false swearing in his answer to a plaintiff's bill.

The punishments of perjury by the common law were -discretionary fine and imprisonment; the pillory, which punishment was abolished (by 1 Vict. c. 28) in 1837; and a perpetual incapacity to give evidence in courts of justice. The present penalties of perjury are fixed by statute: they are fine, imprisonment, and transportation for seven years. In Scotland, where statute does not enact the punishment, the crime is punished by imprisonment since the abolition of the pillory, which was at one time the punishment.

Oaths may now be dispensed with in many cases, if the person has a conscientious objection to them, but a false declaration or affirmation subjects the offender to all the penalties of perjury. [OATH.]

PERM, an extensive government of Russia, is situated partly in Europe and partly in Asia, between 55° 30' and 61° 30′ N. lat., and 53° 20' and 65° 10′ E. long. It is bounded on the N. by Wologda and Tobolsk, on the E. by Tobolsk, on the S. by Orenburg, and on the W. by Viatka. The area is estimated at 128,600 square miles, and the population, at the last census, was 2,046,572.

The government is mountainous, and is divided by the Ural mountains, which traverse it from north to south, into two unequal parts, the smaller of which is in Asia. More than three-fourths of the surface are covered with dense forests, in some of which there are immense marshes. The southern parts, on the European side, are fertile and well cultivated, but the other portions are more suitable to pasture than tillage. The principal

Perm was formerly the centre of an extensive and flourishing empire, which was ruined by the Mongols in the thirteenth century. Three-fourths of the inhabitants are Russians, the remainder Permians. Nearly all profess Christianity.

There are some manufactures of cloth, leather, soap, candles, &c. Trade is very brisk, partly in consequence of the facility for water-carriage.

Perm, the capital of the government, is a modern town, having been built in obedience to a ukase of Catherine II., issued in 1780. It is situated in 58° N. lat. and 56° 30′ E. long., at the conflux of the Iagouschika and the Kama. The streets are broad and regular, the houses almost all of wood, and the town is surrounded by a boulevard planted with trees. It is the see of an archbishop, and has several churches and hospitals. There are some iron forges, and a steel foundry was established by the government in 1865. The inhabitants, who number about 14,000 altogether, trade chiefly in metallic produce, tea, and other Chinese imports, by way of Kiakhta. There are eleven other districts in the government, but the only large towns are EKATERINBURG; Kungour, 42 miles S.E. of Perm, on the Silva, with 8400 inhabitants, which contains some tanneries, famous for their Russia leather, and has some iron-works in the vicinity; Nijny Tagilsk, a town in the Ural mountains, 135 miles E. of Perm, with a population of 27,000, the chief Zavod of the Demidoff family, has copper mines, an observatory, forges, and manufactures of machinery; Neviansk, on the Neiva, 50 miles N. of Ekaterinburg, which has 18,000 inhabitants, and is celebrated for its metallurgic riches, and its mint, the tower of which leans more than that of Pisa; and Irbit, a Siberian town 100 miles E.N.E. of Ekaterinburg, on the Nitsa, and on a route from Tobolsk into Europe, which is inclosed by a palisade, and is chiefly noted for a large annual fair, lasting for a month, in February and March, and attended by a great concourse of European and Asiatic merchants. It is, after that of Nijni Novgorod, the most important fair in the Russian empire. A line of steam-packets was established in 1863 between this place and the towns on the Tobol, Irtish, and Obi.

PERMIAN LIMESTONE, the name given to the laminated, brecciated, fossiliferous, and compact magnesian limestones of the Permian series of rocks, as they are developed especially in Durham and Yorkshire. These are severally represented on the Continent by the German stinkstein, rauchwake, dolomite, and zechstein. These beds are associated with parti-coloured marls gypseous marls, and marl slates. [GEOLOGY.]