ERA 



ERA 



Arsenic acid. . 57*68 Lime 28 



Muriatic acid 37 Magnesia... 20 



Nitric acid ... 54 Potash 48 



Sulphuric acid 40 Soda 32 



Thus 57'68 of arsenic acid, 37 of muri- 

 atic, 54 of nitric, and 40 of sulphuric, 

 combine with 28 of lime, forming, re- 

 spectively, a neutral arseniate, muriate, 

 nitrate, and sulphate of lime ; &c. &c. 



E'QUIVALVED. A term applied to 

 bivalves, when the two valves are of 

 equal size and depth. 



EQUI'VOCAL NOUN {csqud, equally, 

 voco, to call). In Logic, a noun which has 

 more than one signification, each of its 

 significations being equally applicable to 

 several objects, as bull — the animal ; the 

 pope's official letter ; a blunder. "Strictly 

 speaking, there is hardly a word in any 

 language which may not be regarded, as 

 in this sense, equivocal ; but the title is 

 usually applied only in any case where a 

 word is employed equivocally ; e. g. where 

 the middle term is used in diflferent 

 senses in the two premises ; or where a 

 proposition is liable to be understood in 

 various senses, according to the various 

 meanings of one of its terms." — Whately. 

 EQUU'LEUS PICTO'RIS. The Paint- 

 er's Horse, or Easel ; a modern southern 

 constellation, consisting of eight stars, 

 situated close to the principal star of Argo. 

 E'QUULUS. The Horse's Head; a 

 northern constellation, consisting of ten 

 stars. 



E'RA or iERA. A fixed point of time, 

 at which the computation of ensuing 

 years is commenced. The following are 

 the principal eras : — 



1. Era of the Olympiads. The most 

 ancient method of computing time, first 

 instituted in the year b.c. 776, and con- 

 sisting of a revolution of four years. It 

 originated from the Olympic games, 

 which were celebrated every fifth year 

 at Olympia, a city of Elis in Greece. 



2. Era of the Foundation of Rome. 

 This has been variously fixed. The 

 Varronian computation, which fixes it in 

 the year b.c. 753, was adopted by the 

 Roman emperors, and has received the 

 sanction of most modern chronologists. 



3. Christian Era. This commenced 

 Jan. 1, in the middle of the fourth year 

 of the 194th Olympiad, the 753rd of the 

 building of Rome, and the 4714th of the 

 Julian period. The years of this era are 

 described in ancient documents as the 

 years " of Grace," of " the Incarnation," 

 of " the Nativity," of " the Circumcision," 

 and '* annus Trabeationis." 



4. Julian Era. The era of the reform- 

 ation of the Roman Calendar by Julius 

 Caesar, who ordained that the year of 

 Rome 707 should consist of 15 months, 

 forming altogether 445 days; that the 

 ensuing year, 708, should consist of 365 

 days ; and that every fourth year should 

 contain 366 days, the additional day 

 being introduced after the 6th of the 

 calends of March, i.e. the 24th of Febru- 

 ary, which year he called bissextile, be- 

 cause the 6th of the calends of March 

 was then doubled. 



5. The Indictions. The Indictions 

 consisted of a revolution of fifteen years, 

 which are separately reckoned as Indic- 

 tion 1, Indiction 2, &c., up to 15, when 

 they recommence with 1. The first In- 

 diction is usually referred to the year 

 A.D. 313. See Indictions. 



6. Mundane Era of Alexandria. The 

 Alexandrian era of the Creation of the 

 World was fixed at 5502 years before 

 Christ, This computation Avas continued 

 until A.D. 284, or the year 5786 of the 

 Alexandrian era; but in the following 

 year, ten years were subtracted, and that 

 year was accordingly a. alex. 5777. 



7. Mundane Era of Antioch. By this 

 era, the Creation of the World was fixed 

 at 5492 years before Christ, or ten years 

 later than by the era of Alexandria. As, 

 however, ten years were subtracted from 

 the Alexandrian era in a.d. 285, the two 

 eras thenceforward coincided. 



8. Era of Constantinople. This era 

 refers the Creation of the World to the 

 5508th year before Christ, and is still 

 used by the Greek Church. In this era 

 there are two years : the civil, which be- 

 gins with the month of September ; and 

 the ecclesiastical, which commences on 

 the 21st of March, and sometimes on the 

 1st of April. 



9. Era of the Seleucidce. This era, 

 also called the "Era of the Greeks," 

 sometimes the '* Era of Alexandria," and 

 occasionally the " Era of the Syro- 

 Macedonians," commenced in the year 

 of Rome 442, twelve years after the 

 death of Alexander, and 311 years and 

 4 months before the birth of Christ, being 

 the epoch of the conquest of Babylon by 

 Seleucus I., surnamed Nicator, or the 

 Victorious. It is still used in the Levant. 



10. C cesarean Era of Antioch. This 

 era was instituted at Antioch, in conse- 

 quence of the victory gained by Julius 

 Caesar in the plain of Pharsalia, on the 

 9th of August, in the year of Rome 706, 

 and 48 years before Christ. 



