2. The Egyptians made use of the Dog-star, Slria- cal, or Soihic Period, as it is variously called, to com- pare their civil year of 3G5 daj'S with the true or Julian year of 365j days. The period consequently consisted
PERIODENT^
950
PERISTERION
of 1460 Julian years, corresponding to 1-161 Egj'ptian years, after the lapse of wliicli the dates in both reck- onings coincided. By comparing the solar and lunar years, Meton, an Athenian, invented (B.C. 432) a lunar period of 6940 days, called from him the Metonic Cycle, also the Lunar Cycle. About a ccnturj' afterwards the cycle of Meton was discovered to be an insufficient approximation to the truth, and as he had made the solar jear too long by about y'yth of a daj', at the end of 4 Metonic cycles the solar reckoning was in advance of the lunar bj' about 1 day 6 hours. To remedy this, a new period, called the Calippic Perud, was invented by Calippus, and consisted of 4 Metonic cycles less bv' 1 day. or 27,759 days. But as this period still gave a difference of 6 hours between the solar and lunar reck- onings, it was improved by Hipparchus, who invented the Hippaichic Period of 4 Calippic periods less bj' 1 day, or 111,035 days, or about 304 Julian j'ears, which is an exceedingly close approximation, being only 6| minutes too long, when measured by the tropical year ; and too short by an almost inappreciable quantity, when measured bj' the Synodic Month.
3. The period of the Heliacal or Solar Cycle, after which the same day of the month falls upon the same daj' of the week, consists of 28 Julian years. If the year had regularly consisted of 365 days, that is, one daj' more than an exact number of weeks, it is evident that at the end of seven j'cars the days of the month and week would again correspond ; but the introduc- tion of an intercalary da}' into every fourth year causes this coincidence to recur at irregular periods of 6, 11, 6, and 5 years successively. However, by choosing a period such as will preserve the leap-v'ears in the same relative position to the other years, and at the same time consist of an exact number of weeks (both of which objects are effected by using the number 28, which is the least common multiple of 4 and 7), we in- sure the regular recurrence of the coincidence between the days of the week and of the month. The solar cycle is supposed to have been invented about the time of the Council of Nice (A.D. 325), but it is ar- ranged so that the first 3-ear of the first cjcle corre- sponds to B.C. 9. In calculating the position of any 3'ear in the solar cycle, care must be taken to allow for the omission of the intercalar}' day at the begin- ning of each century, and its insertion in the first j'ear of ever}' fourth century.
4. The Julian Period is a cycle of cycles, and con- sists of 7980 ( = 28 X 19 X 15) years, after the lapse of which the solar cycle, lunar cycle, and the Indiction (q. V.) commence together. The period of its com- mencement has been arranged so that it will expire at the same time as the other three periods from which it has been derived. The year 4713 B.C. is taken as the first year of the first period, consequently A.D. 1 was the 4714th. — Chambers.
Periodentee, a name given to itinerating or vis- iting presbyters decreed by the Council of Laodicea, A.D. 360, to supersede the Chorepiscopi (q. v.) in the country villages.
Pei'ion, Joachim, a learned Frenchman, was born about 1499 at Cormery (Touraine). in 1517 he took the religious habit of the Benedictines in tlie abbey of Cormery ; came to Paris in 1527, and was there received as doctor of tlieology in 1542. He sometimes gave liiniself the honnrary title of interpreter to the king. Me possessed tiie talents for it, if he did not do the work ; for he made the study of ancient languages tiie occupation of his whole life. He professed a su- perstitious admiration for Cicero, and he regarded Aristotle as the oracle of the school ; he also delivered against K'anuis, who did not share in his fondness, three harangues full of invectives. Perion died at Cormery in 1559 ; or, according to Dom Liron, in 1561. We have of his works, De fabiilirnm, bidorum, theatrorum anti- qua tonsuetudlne ^Paris, 1540, 4to) : — Topicoritm theolo-
fficornm lib. it (ibid. 1549, 8vo); he supports the Cath- olic doctrine by well-chosen extracts from Scripture and from the fathers : — De vHls et rebus gestis aposto- lorum (ibid. 1551, 16mo), translated into French in 1552 : — De vita rthmqae gestis J. C, Marice Virginis, et Johannis Baptisto' (ibid. 1553, 16mo) : ■ — De origine lingua; Gullicm et ejus cum Graca cognatione diutogo- rum lib. iv (ibid. 1555, &vo) ; this treatise, divided into four parts, falls below criticism, but is not so bad as La Monnoye pretends, and contains some curious particulars: — Z>d sunetorum virorum qui patriarchce ab ecclesia apjiel/antur rebus gestis ac vitis (ibid. 1555, 4to), transhited into French : — De magistralihus Ro- manorum ac Gracoruni (ibid. 1560, 4to), and in the Aniiq. Gr. of Gronovius. The numerous Latin ver- sions of Dom Perion are more elegant than faithful, and derive their principal merit from the time in which they appeared. We cite only those from Aristotle (1540-59, 7 vols.) ; from the Traiie des Heresies of John of Damascus (1548, fol.) ; from the CEuvres of Saint Justin (1554, fol.), and from Saint Denis the Areopa- gite (1556, fol.), etc. See Sccvole de Sainte-Marthe, Elogia, lib. i; Teissier, Eloges; Hilarion de Coste, Vie de Frangois Le Pic ird, p. 335 ; La Jlonnoye, Notes sur " la Biblioth. de La Croix du Maine f Essais de Litlera- tire, Nov. 1702; Niccron, Memnires, vol. xxxvi. — Hoefer, Xouv. Blog. Generale, xxxix, 613.