FERGUSSON. 543 FERMAT. cesses which impaired his health. He became melancholy, and, after a fall down a stairway, insane. In 17SII liurns placed over lii- grave a me rial bearing a verse epitaph. Kcrgusson, a lluent and natural versifier in the Scotch dia- lect, was the forerunner of Burns. Consult: Works, edited with Life, and Essay on Poetical Genius by Grosart (Edinburgh, 18.51); and Ward. English Poets, vol. iii. (London and New York, 1889) . FERGUSSON, Sir William (1808-77). An English surgeon. He was born at Prestonpans, Scotland, and was educated at Edinburgh. In 1831 he was elected surgeon of the Edinburgh Royal Dispensary, and after 1830 he served in the same capacity at the Royal Infirmary, lie afterwards successively became professor of sur- gery at King's College, London (1840-70) ; sur- geon in ordinary to the Prince Consort (184!U, and to the Queen (1867) ; president of the Royal College of Surgeons (1870), and clinical professor • I surgery at King's College (1870-77). He was for many years the leading operator in London, and was the inventor of numerous ingenious sur- gical instruments, such as the 'bulldog' forceps and the mouth-gag for cleft palate. He was especially successful with the operations for hare- lip and cleft palate, and for the amputation of limbs. His principal work is the System of Practical Surgery (5th ed. 1870). FE'RI^ (Lat., holidays). Holidays during which political and legal transactions were sus- pended in ancient Rome, and slaves enjoyed a cessation from labor. Feria? were thus dies nefasli, the opposite of the dies fasti. (See Fasti.) Days which were consecrated to a par- ticular divinity, on which any public ceremony was celebrated, and the like, were feriae. In con- tradistinction to these, which were ferice publico; (public holidays), there were ferice privates, which were observed by single families, in com- memoration of some particular occurrence of importance to them or their ancestors. Birth- days, days of purification after a funeral, etc.. were also observed as family ferioe. The public feri.T were divided into those which were always kept (stativas) on certain days marked in the calendar, and those which were kept by com- mand of the consuls or other superior magistrates on the occasion of any public emergency i im- peratival). There were forty-five fixed holidays in ancient Rome, and a large number of movable ferine, the most important of which were the ferice latinos, the original common festival of the Latin tribes, held on the top of the Alban Mount, afterwards carried to Rome along with the su- premacy over Latium; the ferine sementives or sowers' festival, in the spring; and the ferice oindemialcs, or vintage festival, in the fall. FERISHTAH, or FIRISHTAH, fe-resh'ta, Mohammed Kasim Hixoushah (c. 1550-c. 1012). A Persian historian, born at Astrabad. Under mission from Ibrahim Adil Shah (1585- 1028), he wrote the Tarilh-i-Ferishtah, n history of the Mahammedan dynasties of India from about the end of the tenth century, with an in- troduction on Indian history previous to Moham- medan dominion. This work is considered one of the must reliable of Oriental histories. It »»< translated into English by Dow (2 vols., 1768) and Briggs (4 vols'., 1832). FERLAND, far'la.x'. ,li an I: roiNE 1 ]*"■"' 04), A Canadian clergyman and hi torian, born in Montreal. In 1828 he was ordaini d I pi iesi of i he Roman ' atholic < Ihurch, and was made icai of Quebec. In L847, while profi in the Seminar; of tvieolet, he distinguished him -elt for his courage during an • pidei of tj phoid fever. He was appointed professor of history in the Laval University in is:,;,. His reputation as an historian rests on his Court d'hi toin du Canada i vol ; i.. 1861 ; vol. ii. by La r< rdii n 1865), in which an attempt is made to harmonize the confused accounts of the early settlers. FERMANAGH. fSr man's or f§r-ma'na (named from the Irish clan Fir tonach, men of Monach). An inland county in the southwest oi the Province of Ulster, Ireland (Map: Ireland, D 2). Area, 714 square miles. The chief towns are Fermanagh and Enniskillcn. The population, chiefly engaged in agriculture, shows a gradual decline since IS41, when it was 156,850, In 1S51 it was 116,400; in 1891, 74,170; in 1901, 05.240. FERMAT, far'ma'. Pierke he (1001-05). A French mathematician, horn at Beaumont-de- Lomagne, near Montauban. He was one of the most versatile mathematicians of his time, and was unsurpassed as a contributor to the theory of numbers. Fermat was educated privately, was of a retiring disposition, and published little dur- ing his lifetime. At one time he turned his attention to law, and in 1631 became counselor for the Parliament of Toulouse. The first edition of his works, gathered from his papers, annota- tions, and personal letters, was published in two volumes unter the title, Opera Mathcmatiea i 1070- 79) . Copies of this edition have become quite rare. The first volume contains the Arithmetic of Diophantus annotated, and the second, mono- graphs on maxima and minima tangents, and centres of gravity, and copies of his correspon- dence with Huygens, Pascal, Descartes, and others. His chief contributions to the theory of numbers are found in his commentaries on Dio- phantus. Among them are such well-known propositions as follow: If a is prime to p. p being a prime number, then av~' — 1 is divisible by /', or. expressed in the notation of congruences (q.V.), ai'" 1 — 1=0 (mod. p) . A prime greater than 2 can be uniquely expressed as the difference of two squares. p*--q~. where p is prime to g, is not divisible by a prime of the form 4h — 1. If p, g. r, are integers such that p- + q 2 =r 2 , then /»'/ cannot be a square. The equation x* -4- 2=//"' has a unique solution, and the equation x- -f- 4 = ;/ 3 has two solutions. The equation a,D + :V n = s ° has no integral root if n is integral and greater than 2. In the case of particular curves. Fermat obtained the maximum and mini- mum values of their functions; also the sub- tangents of the ellipse, cycloid, conchoid, and quadratrix. The methods employed so resembled those afterwards developed through the differen- tial calculus that some mathematicians, espe- cially Laplace and Lagrange, have suggested IViinai a- the inventor of the calculus. The rise of the theory of probability (see Probability) may l»' dated practically from the correspondence of Fermat and Pascal (1054). Fennat's an- swers to the problems suggested by Pascal re- veal his firm grasp on the fundamental princi-
