Authorities.—The standard treatise in English is H. D. Taylor, A System of Applied Optics (1906); reference may also be made to R. S. Heath, A Treatise on Geometrical Optics (2nd ed., 1895); and L. A. Herman, A Treatise on Geometrical Optics (1900). The ideas of Abbe were first dealt with in S. Czapski, Theorie der optischen Instrumente nach Abbe, published separately at Breslau in 1893, and as vol. ii. of Winkelmann’s Handbuch der Physik in 1894; a second edition, by Czapski and O. Eppenstein, was published at Leipzig in 1903 with the title, Grundzüge der Theorie der optischen Instrumente nach Abbe, and in vol. ii. of the 2nd ed. of Winkelmann’s Handbuch der Physik. The collection of the scientific staff of Carl Zeiss at Jena, edited by M. von Rohr, Die bilderzeugung in optischen Instrumenten vom Standpunkte der geometrischen Optik (Berlin, 1904), contains articles by A. König and M. von Rohr specially dealing with aberrations. (O. E.)
ABERSYCHAN, an urban district in the northern parliamentary division of Monmouthshire, England, 11 m. N. by W. of Newport, on the Great Western, London and North-Western, and Rhymney railways. Pop. (1901) 17,768. It lies in the narrow upper valley of the Afon Lwyd on the eastern edge of the great coal and iron mining district of Glamorganshire and Monmouthshire, and its large industrial population is occupied in the mines and ironworks. The neighbourhood is wild and mountainous.
ABERTILLERY, an urban district in the western parliamentary division of Monmouthshire, England, 16 m. N.W. of Newport, on the Great Western railway. Pop. (1891) 10,846; (1901) 21,945. It lies in the mountainous mining district of Monmouthshire and Glamorganshire, in the valley of the Ebbw Fach, and the large industrial population is mainly employed in the numerous coal-mines, ironworks and tinplate works. Farther up the valley are the mining townships of Nantyglo and Blaina, forming an urban district with a population (1901) of 13,489.
ABERYSTWYTH, a municipal borough, market-town and seaport of Cardiganshire, Wales, near the confluence of the rivers Ystwyth and Rheidol, about the middle of Cardigan Bay. Pop. (1901) 8013. It is the terminal station of the Cambrian railway, and also of the Manchester and Milford line. It is the most popular watering-place on the west coast of Wales, and possesses a pier, and a fine sea-front which stretches from Constitution Hill at the north end of the Marine Terrace to the mouth of the harbour. The town is of modern appearance, and contains many public buildings, of which the most remarkable is the imposing but fantastic structure of the University College of Wales near the Castle Hill. Much of the finest scenery in mid-Wales lies within easy reach of Aberystwyth.
The history of Aberystwyth may be said to date from the time of Gilbert Strongbow, who in 1109 erected a fortress on the present Castle Hill. Edward I. rebuilt Strongbow’s castle in 1277, after its destruction by the Welsh. Between the years 1404 and 1408 Aberystwyth Castle was in the hands of Owen Glendower, but finally surrendered to Prince Harry of Monmouth, and shortly after this the town was incorporated under the title of Ville de Lampadarn, the ancient name of the place being Llanbadarn Gaerog, or the fortified Llanbadarn, to distinguish it from Llanbadarn Fawr, the village one mile inland. It is thus styled in a charter granted by Henry VIII., but by Elizabeth’s time the town was invariably termed Aberystwyth in all documents. In 1647 the parliamentarian troops razed the castle to the ground, so that its remains are now inconsiderable, though portions of three towers still exist. Aberystwyth was a contributory parliamentary borough until 1885, when its representation was merged in that of the county. In modern times Aberystwyth has become a Welsh educational centre, owing to the erection here of one of the three colleges of the university of Wales (1872), and of a hostel for women in connexion with it. In 1905 it was decided to fix here the site of the proposed Welsh National Library.
ABETTOR (from “to abet,” O. Fr. abeter, à and beter, to bait, urge dogs upon any one; this word is probably of Scandinavian origin, meaning to cause to bite), a law term implying one who instigates, encourages or assists another to commit an offence. An abettor differs from an accessory (q.v.) in that he must be present at the commission of the crime; all abettors (with certain exceptions) are principals, and, in the absence of specific statutory provision to the contrary, are punishable to the same extent as the actual perpetrator of the offence. A person may in certain cases be convicted as an abettor in the commission of an offence in which he or she could not be a principal, e.g. a woman or boy under fourteen years of age in aiding rape, or a solvent person in aiding and abetting a bankrupt to commit offences against the bankruptcy laws.
ABEYANCE (O. Fr. abeance, “gaping”), a state of expectancy in respect of property, titles or office, when the right to them is not vested in any one person, but awaits the appearance or determination of the true owner. In law, the term abeyance can only be applied to such future estates as have not yet vested or possibly may not vest. For example, an estate is granted to A for life, with remainder to the heir of B, the latter being alive; the remainder is then said to be in abeyance, for until the death of B it is uncertain who his heir is. Similarly the freehold of a benefice, on the death of the incumbent, is said to be in abeyance until the next incumbent takes possession. The most common use of the term is in the case of peerage dignities. If a peerage which passes to heirs-general, like the ancient baronies by writ, is held by a man whose heir-at-law is neither a male, nor a woman who is an only child, it goes into abeyance on his death between two or more sisters or their heirs, and is held by no one till the abeyance is terminated; if eventually only one person represents the claims of all the sisters, he or she can claim the termination of the abeyance as a matter of right. The crown can also call the peerage out of abeyance at any moment, on petition, in favour of any one of the sisters or their heirs between whom it is in abeyance. The question whether ancient earldoms created in favour of a man and his “heirs” go into abeyance like baronies by writ has been raised by the claim to the earldom of Norfolk created in 1312, discussed before the Committee for Privileges in 1906. It is common, but incorrect, to speak of peerage dignities which are dormant (i.e. unclaimed) as being in abeyance. (J. H. R.)
ABGAR, a name or title borne by a line of kings or toparchs, apparently twenty-nine in number, who reigned in Osrhoene and had their capital at Edessa about the time of the Christian era. According to an old tradition, one of these princes, perhaps Abgar V. (Ukkāmā or Uchomo, “the black”), being afflicted with leprosy, sent a letter to Jesus, acknowledging his divinity, craving his help and offering him an asylum in his own residence, but Jesus wrote a letter declining to go, promising, however, that after his ascension he would send one of his disciples. These letters are given by Eusebius (Eccl. Hist. i. 13), who declares that the Syriac document from which he translates them had been preserved in the archives at Edessa from the time of Abgar. Eusebius also states that in due course Judas, son of Thaddaeus, was sent (in 340＝A.D. 29). In another form of the story, derived from Moses of Chorene, it is said further that Jesus sent his portrait to Abgar, and that this existed in Edessa (Hist. Armen., ed. W. Whiston, ii. 29-32). Yet another version is found in the Syriac Doctrina Addaei (Addaeus＝Thaddaeus), edited by G. Phillips (1876). Here it is said that the reply of Jesus was given not in writing, but verbally, and that the event took place in 343 (A.D. 32). Greek forms of the legend are found in the Acta Thaddaei (C. Tischendorf, Acta apostolorum apocr. 261 ff.).
These stories have given rise to much discussion. The testimony of Augustine and Jerome is to the effect that Jesus wrote nothing. The correspondence was rejected as apocryphal by Pope Gelasius and a Roman Synod (c. 495), though, it is true, this view has not been shared universally by the Roman church (Tillemont, Mémoires, i. 3, pp. 990 ff.). Amongst Evangelicals the spuriousness of the letters is almost generally admitted. Lipsius (Die Edessenische Abgarsage, 1880) has pointed out anachronisms which seem to indicate that the story is quite unhistorical. The first king of Edessa of whom we have any trustworthy information is Abgar VIII., bar Maʽnu (A.D. 176–213). It is suggested that the legend arose from a desire to trace the christianizing of his kingdom to an apostolic source.
