EPOCHA
, or Epoch, a term or fixed point of time, from whence the succeeding years are numbered or reckoned.
Different nations make use of different Epochs. The christians chiefly use the Epoch of the nativity or incarnation of Jesus Christ; the Mahometans, that of the Hegira; the Jews, that of the creation of the world, or that of the Deluge; the ancient Greeks, that of the Olympiads; the Romans, that of the building of their city; the ancient Persians and Assyrians, that of Nabonassar; &c.
The doctrine and use of Epochs is of very great extent in chronology. To reduce the years of one Epoch to those of another, i. e. to find what year of one corresponds to a given year of another; a period of years has been invented, which, commencing before all the known Epochs, is, as it were, a common receptacle of them all, called the Julian Period. To this period all the Epochs are reduced; i. e. the year of this period when each Epoch commences, is determined. So that, adding the given year of one Epoch to the year of the period corresponding with its rise, and from the sum subtracting the year of the same period corresponding to the other Epoch, the remainder is the year of that other Epoch.
Epoch of Christ, is the common Epoch throughout Europe, commencing at the supposed time of our Saviour's nativity, December 25; or rather, according to the usual account, from his circumcision, or the 1st of January. The author of this Epoch was an Abbot of Rome, one Dionysius Exiguus, a Scythian, about the year 507 or 527. Dionysius began his account from the conception or incarnation, usually called the Annunciation, or Lady Day; which method obtained in the dominions of Great Britain till the year 1752, before which time the Dionysian was the same as the English Epoch: but in that year the Gregorian calendar having been admitted by act of parliament, they now reckon from the first of January, as in the other parts of Europe, except in the court of Rome, where the Epoch of the Incarnation still obtains for the date of their bulls. |
| ATABLE of the Years of the most remarkable Epochs or Eras and Events. | |||
| N. B. The years before Christ, are those before the reputed year of his birth, and not reckoned back from the first year of his age, as is generally done in such tables. | Julian Period. | Year of the World. | Years before Christ. |
| The Creation of the World | 706 | 0 | 4007 |
| The Deluge, or Noah's flood | 2362 | 1656 | 2351 |
| Assyrian monarchy founded by Nimrod | 2537 | 1831 | 2176 |
| The birth of Abraham | 2714 | 2008 | 1999 |
| Kingdom of Athens founded by Cecrops | 3157 | 2451 | 1556 |
| Entrance of the Israelites into Canaan | 3262 | 2556 | 1451 |
| The destruction of Troy | 3529 | 2823 | 1184 |
| Solomon's temple founded | 3701 | 2995 | 1012 |
| The Argonautic expedition | 3776 | 3070 | 937 |
| Lycurgus formed his laws | 3829 | 3103 | 884 |
| Arbaces, 1st king of the Medes | 3838 | 3132 | 875 |
| Olympiads of the Greeks began | 3938 | 3232 | 775 |
| Rome built, or Roman Era | 3961 | 3255 | 752 |
| Era of Nabonassar | 3967 | 3261 | 746 |
| First Babylonish captivity, by Nebuchadnezzar | 4107 | 3401 | 606 |
| The 2d ditto, and birth of Cyrus | 4114 | 3408 | 599 |
| Solomon's temple destroyed | 4125 | 3419 | 588 |
| Cyrus began to reign in Babylon | 4177 | 3471 | 536 |
| Peloponnesian war began | 4282 | 3576 | 431 |
| Alexander the great died | 4390 | 3684 | 323 |
| Captivity of 100,000 Jews by Ptolomy | 4393 | 3687 | 320 |
| Archimedes killed at Syracuse | 4506 | 3800 | 207 |
| Julius Cæsar invaded Britain | 4659 | 3953 | 54 |
| He corrected the calendar | 4667 | 3961 | 46 |
| The true year of Christ's birth | 4709 | 4003 | 4 |
| The Christian Era begins here. | Years since Christ. | ||
| Dionysian, or vulgar era of Christ's birth | 4717 | 4007 | 0 |
| Christ crucified, Friday April 3d | 4746 | 4040 | 33 |
| Jerusalem destroyed | 4783 | 4077 | 70 |
| Adrian's wall built in Britain | 4833 | 4127 | 120 |
| Dioclesian Epoch, or that of Martyrs | 4997 | 4291 | 284 |
| The council of Nice | 5038 | 4332 | 325 |
| Constantine the great died | 5050 | 4344 | 337 |
| The Saxons invited into Britain | 5158 | 4452 | 445 |
| Hegira, or flight of Mohammed | 5335 | 4629 | 622 |
| Death of Mohammed | 5343 | 4637 | 630 |
| The Persian Yesdegird | 5344 | 4638 | 631 |
| Sun, Moon, and Planets in , seen from the earth | 5899 | 5193 | 1186 |
| Art of printing discovered | 6153 | 5447 | 1440 |
| The reformation begun by Martin Luther | 6230 | 5524 | 1517 |
| The Calendar corrected by pope Gregory | 6295 | 5589 | 1582 |
| Oliver Cromwell died | 6371 | 5665 | 1658 |
| Sir Isaac Newton born, Dec. 25 | 6355 | 5649 | 1642 |
| Made President of the Royal Society | 6416 | 5710 | 1703 |
| Died, March 20th | 6440 | 5734 | 1727 |
| New Planet discovered by Herschel | 6494 | 5788 | 1781 |
EQUABLE Motion, Celerity, Velocity, &c, is that which is uniform, or without alteration, or by which equal spaces are passed over in equal times. Hence, the spaces, passed over in Equable motions, are proportional to the times. So that if a body pass over 20 feet in 1 second of time, it will pass over 40 feet in 2 seconds, and so on.
Equably Accelerated or Retarded, &c, is when the motion or change is increased or decreased by equal quantities or degrees in equal times.
