I R V 



uera! fenfe, the capability of being irritated or excited, or that 

 property by which hving parts are enabled to execute their 

 fimftions : when thus employed, it is fynonymous with ex- 

 citability, and may be regarded as denoting the moll cha- 

 raclenllic peculiarity of hving matter. It is very commonly 

 employed, in a more limited acceptation, to exprefs the 

 property by which mufcles are enabled to contraft, either 

 in obedience to the will, or to any mechanical or chemical 

 ftimuh. In either cafe, this word is to be underftood as 

 fignifying merely a property of living bodies, the real na- 

 ture of which is as entirely unknown to us as that of attrac- 

 tion or chemical affinity. All the fpecidations which have 

 been entertained on the fubje£l of its nature, fuppollng it to 

 be a peculiar fubtle matter like thoie (whofe exiftence, be 

 it obferved, rells alfo on fuppofition) of electricity com- 

 mon or Voltaic, of magnetifra or light, or confidering it as 

 identical with oxygen, may be difmiifed without any formal 

 refutation, as they are completely gratuitous a'.Tumptions. 

 See Life, Muscle, and Nekve. 



IRRITATION, in jll.Jidnc, fignifiesa ftate of feverifh- 

 nefs and inquietude, in which the funftions are impeded, 

 and the rtrength gradually impaired, arifing either from in- 

 ternal or external caufes, but principally from the former. 

 It is fynonymous with the erethifm, l^s^is-^i;, of the Greek 

 ■writers. Irritation is produced, in different inftanccs, by 

 extraneous fubftances in the cavities or organs of the body, 

 as calcuh in the bladder, kidnies, or ureters ; worms in the 

 ftomach or inteftines, &c. ; or by chronic difeafe in the 

 vifcera, fuch as fcinhus of the liver, of the mefenteric 

 glands, &c. ; or flow inflammation in any part ; or by the 

 prevalence of any depreffing paffion, as grief and anxiety ; 

 or by long watching ; and various other caufes. In febrile 

 difeafes, from whatever origin, a ftate of irritation is more 

 readily produced ; i. e. the fame ftimuh which excite little 

 effedl in the ftate of health, tend to aggravate the feverifli 

 fymptoms, fuch as external heat, ftrong light, noifes, muf- 

 cular or mental exertion, and the like : whence, in every 

 fever, whether idiopathic or fymptomatic, the removal of 

 every fource of irritation is an indication conftantly to be 

 ■kept in view. 



IRRSUMIT, in Geography, a town of Eaft Greenland. 

 N. lat. 6l lo'. W. long. 45 35'. 



IRSOA, a fmall ifland near the coaft of Portugal, on 

 the fouth fide of the mouth of the Minho. N. lat. 41 50'. 

 W. long. 8^ :?6'. 



IRTISCH, or Irtysh, a river of Ruffia, which rifes 

 in the Chinefe Soongoria, flows through the lake Norfnifan, 

 in N. lat. 46" 30', then enters the Ruffian territory, and 

 after meandering through a large traft of country, throws 

 itfelf, in N. lat 61% and E. long. 56 , into the Oby. In 

 its way it takes up feveral fmaller rivers, and forms feveral 

 iflands, of which fome occafionally difappear, and their 

 places are fupplied by others ; and the intervals in which it 

 is navigable are perpetually changing. Its water in the 

 inferior regions is whitilh and light, fo that it ffiould feem 

 to flow over a bottom conliiling chiefly of calcareous marie. 

 It fwarms with fi(h, and its fturgeons have a peculiar deli- 

 tate flavour. 



IRVINE, or Irewin-e, a fea-port town and royal bo- 

 rough in the bailiwick of Cunningham, and county of Ayr, 

 Scotland, is feated on the northern bank of the river Irvine, 

 fhe.eftuary of which forms the liarbour. On the fouthern 

 fAe of the river is a row of boufes uniformly built ; and 

 thefe, with others, are hamlets to the parilh of Dundonald. 

 The town appears to have been chartered at an early 

 period; for in a grant from Alexander II., reference is 

 RMie to previous charters. The magiilracy ot this towa 

 2 



I S A 



had formerly extenfive jurifdiiflion, but this has been 

 abridged ; but it ftill derives an ample revenue from a large 

 traft of land near the town. Here is a commodious har- 

 bour, which has 10 or 12 feet of water on the bar at fpring- 

 tides. Several vefTcls, called budes, were formerly em- 

 ployed in the herring-tiihery : at prefent the coal-trade is 

 the chief objeft with the inhabitants. Above 24,000 tons 

 have been (hipped from this port in one year. Attached to 

 the town is a dock-yard for fliip-bnilding, a large tan-yard, 

 rope-ground, and a bleach-fitid. Many of the inhabitants 

 are alfo engaged in the manufaftory of carpets, muflins, 

 filks, lawns, and other articles. In the year 1800, the 

 town contained 729 houfes, and 4584 inhabitants ; though 

 its population was eftimated, in 1790, at 3500. The town 

 is 61 miles W. by S. from Edinburgh. The church is de- 

 fcribed as a prominent objeft of beauty and intereft in the 

 town. Bowtree hill, in the vicinity of Irvine, is a feat of 

 the honourable Mr. Hamilton ; and near it is an old caiUe, 

 belonging to the earl of Eghngtown, who has a feat in the 

 neighbouring parifli of Kilwining. In the parifli of Irvine 

 it is faid that a religious feet called Buchannites, from the 

 name of the founder, had its origin. Sinclair's Statiftical 

 Account of Scotland, vol. vii. p. 169, &c. by the Rev. 

 James Richm.ond. 



ISA, in Hindu Mythology, one of the thoufand names of 

 Siva, the perfoniiication of the deltruclive or regenerative 

 power of the deity. (See Siva.) With the epithet Maha, 

 or great, prefixed, Mahefa is formed, another of Siva's 

 names. In this form, the name of his confort or fakti (fee 

 Sakti) is Ifi. Under thefe names fir William Jones re- 

 cognizes the Ofiris and Ifis of Egypt. Ifwara feenis but 

 another mode of writing and pronouncing Ifa ; and the de- 

 duction of Ofiris from that found is no (trained etymology, 

 efpecially when confirmed by many hiftorical and charac- 

 teriftic coincidences. Ifa and Ifi are both perfonitications 

 of the moon ; for with the Hindus, that luminary is both 

 male and female : and here we (ind Parvati (of whom I(i is 

 only another form and name) again correfponding with the 

 Diana of the Greeks, one of whofe names is Luna. 



ISAAC, in Scripture Biography, the fon of Abraham 

 and Sarah, was born at Gerar, in the countrv of the Phi- 

 liftines, B.C. 1896, when his father was ico, and his 

 mother 90 years of age. His birth was prc-vioully an- 

 nounced to Abraham, as the fon of covenant and promifc, 

 in whofe feed all the nations of the earth fhould be bleifed. 

 His name, according to its Hebrew etymology, which de- 

 notes " he has laughed, or ftiall laugh," expreffes the plca- 

 fure with which his parents received the prediction of his 

 birth, and augured the honour that awaited his polterity. 

 A circumlhmce, however, occurred, which tended to abate 

 their joy ; and this was a divine command to offer liaac as a 

 fiicrifice. (See AflHAilA.M.) At the age of 40 years, 

 Ifaac married Rebecca, the daughter of Nahor, Abraliam's 

 brother ; and by her he had two twin-fons, Efau and Jacob. 

 (See their articles.) This venerable patriarch, for whole 

 hillory we refer to the book of Genelis, ch. xviii— xxxv. 

 died at the age of 180 years, B.C. 1716, and was buried 

 with his parents in the cave of Machpelah. 



I.sA.\c I. Co.MXENus, in Biography, emperor of the Eaft, 

 fon of Manuel, was the firft of the noble family of Comneni 

 who arrived at the imperial throne. Ifaac and his brother 

 John were bequeathed by an afle£lionate father, confcioui 

 of his own deierts in the fervice of his country, to the grati- 

 tude and favour of his fovereigu. The noble youths were 

 carefully trained in the learning of the times, the arts of the 

 palace, and the exercifes of the camp ; and had become ex- 

 iremelj popular with the people and the army. On the ele- 

 vation 



