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tain, or limited, but diifers greatly in different children, 

 fome being able to fee clearly at the end of a month, other* 

 not till after many months. 



At the time that this gentleman was diiTefting the eyes 

 of human foetufes and infants, he alfo curioudy obferved 

 the eyes of young quadrupeds. The puppy, when newly 

 brought forth, has always its eyes opaque ; the kitten, on 

 the contrary, has them clear, and every way like thofe of 

 adults of the fame fpecies. In fcctufes of other quadru- 

 peds, the lamb has its cornea a little turbid and opaque ; 

 the Ciilf and the pig have them more or lefs opaque, but the 

 calf fo moit of all. Mem. de I'Acad. Par. 1727. 



Sight, Defeas of. See Cataract ; Gutta Serena ; 

 Leucoma; Ophthalmy; Pterygium ; Trichiasis; Eye, 

 Cancer and Extirpation of ; Epiphora; Y li^rv la Lachry ma- 

 ils ; Staphyloma; Hypopium; ¥vsGVf> Hiematoe/es; Sec. 

 Sight, Short. See Myops and Short-sightedness. 

 Sight, Second. See Second Sigh/. 

 Sight, Point of. See Point of Viciu. 

 Sight, Line of . SeeCoLLijMATioN. 

 Sight. Singing or playing at fight, in Mufic, is the being 

 prepared by long praftice and experience for every difficulty, 

 not only of execution, but ilyles and expreflion : as a per- 

 fon allowed to read well in a book which he has never feen, 

 muft. not only pronounce the words correftly and dillinftly, 

 but obferve the punftuation, and enter into the author's de- 

 fign. We do not always give credit to reports of dilletants, 

 or even every profeflbr, performing a vi/la, or, as the French 

 call it, a li-vre ouvert, all kinds of compofition without ftudy 

 or praftice. See Gretry. 



SIGHTS, in Mathematics, denote two thin pieces of brafs, 

 raifed perpendicularly on the two extremes of an alidade or 

 index of a theodolite, circumferentor, or other like inftru- 

 ment ; each of which has an aperture or flit up the middle, 

 through which the vifual rays pafs to the eye, and diftant 

 objefts are feen. Their ufe is, for the juft direction of the 

 index to the line of the objeft. 



Sometimes the flits or apertures have glalFes or lenfes 

 fitted into them ; in which cafe, they are called telefcopic 

 fights, by way of diftinftion from the former ; which, in 

 refpeft of the others, are denominated plain fights. 



Mr. Flamfteed and Dr. Hooke abfolutely exploded the 

 ufe of plain fights in aftronomical obfervations. The errors 

 in Tycho's latitudes of the ftars Mr. Flamfteed afcribes 

 \yholly to his uling plain fights ; and fufpefts, that Heve- 

 lius, ufing the lame kind of fights, muft fall into the like 

 errors. Hevehus, on the contrary, in a paper in the Philo- 

 fophical Tranfattions, vindicates the ufe ofplain fights, and 

 prefers them to telefcopic ones ; the main objedion he makes 

 to the latter is, that no obfervation can be fafely taken with 

 them, without firft examining and reftifying them ; in which 

 examination, many and grols miftakcs are likely to be com- 

 mitted. To which he adds, that in fextants, oaants, azi- 

 muth quadrants, &;c. he does not fee how fuch examination 

 can be made, at all times, without much lofs of time. 



SIGILLARIA, a folemn feaft held among the ancient 

 Romans ; thus called from a cuttom which obtained therein, 

 of fending little prefents from one to another, confitting of 

 feals, little figures, and fculptures, made of gold, filver, 

 brafs, or even earthenware, and of devoting them to Saturn, 

 as in atonement for themfelves and their friends. 



The Sigillaria followed immediately after the Saturnalia, 

 and held two days ; which, with the five days of the Satur- 

 nalia, made a folemnity of feven days. 



Some derive the origin of figils and figures, in this folem- 

 aity, from the argei, or rulhen figures of men, thrown an- 



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nually into the Tiber, from the Pons Sbblicius, by the 

 Veftals, on the ides of March. Vide Macrob. Saturn, lib. i. 

 cap. 7. 10. and 11. See alfo Argea. 



SIGILLATA Terra, a name given to feveral kinds 

 of medicinal earths marked with feals, to exprefs their being 

 genuine. The principal is the Lemnian earth : this is a kind 

 of earth, or bole, dug in the ifle of Lemnos, and then alfo 

 called Lemnian earth ; of confiderable ufe in medicine. 



It was anciently found in a mountain, in the neighbour- 

 hood of the city Hepha:ftia, where Diana's priefts went, at 

 certain times, with great ceremony, to dig it up. After a 

 Lttle preparation, they made it up into troches, and fealcd 

 them with Diana's feal ; whence the appellation oi figillata. 

 fealed. 



SIGILLO, in Geography, a town of Italy, in Umbria ; 

 1 2 miles N. of Nocera. 



SIGILLUM, a feal, or fignet. 



SiGiLLU.M Maria, Lady's Seal, in Botany, a name by which 

 fome authors have called the bryonia nigra, or black bryony, 

 a climbing plant, common in hedges. 



SIGILMESSA, in Geography. See Sugulmessa. 



SIGINDUNUM, in Ancient Geography, a town of Upper 

 Moefia, on the banks of the Danube, according to Ptolemy. 

 The Itinerary of Antonine marks it on the route from Rimini 

 to Byzantium, between Taurunura and the mount of Gold. 



SIGINNI, a people of Afia, who, according to Strabo. 

 had the fame manners with the Perfians. 



SIGISA, a town of Hifpania, upon the Tader, N.W. 

 of Vergilia. 



SIGISMONDO, in Biography. See India. 



SIGISMUND, emperor of Germany, and king of Hun- 

 gary and Bohemia, was the fon of the emperor Charles IV. 

 of the houfe of Luxemburg. He was born in the year 

 1366, and at an early age was fent to the court of Lewis, 

 king of Hungary, to one of whofe daughters he was be- 

 trothed, with the intention of making him fucceflfor to the 

 throne. During his minority, a party of nobles conferred the 

 crown on Charles, king of Naples, on which event Sigif- 

 mund retired to Bohemia. Charles being afiafiinated by the 

 contrivance of the queen-mother, who was put to death for 

 the crime, Sigifmund aflembled an army, and entering Hun- 

 gary, liberated his wife Mary, who had been imprifoned, 

 and was crowned king when he was in the twentieth year 

 of his age. He feverely revenged the execution of his 

 mother-in-law ; and getting poffefTion of the perfons of the 

 nobles who had invited Charles, he caufed them all to be 

 beheaded, to the number of thirty-two. The bloody aft 

 occafioned fo m.uch difaffeftion, that the Turkifh em- 

 peror Bajazet determined upon taking the opportunity of 

 invading Hungary, which he did with complete fuccefs ; 

 and Sigifmund was dethroned. He however efcaped, and 

 retiring to Bohemia, levied troops, with which he recovered 

 his crown, and being brought to realon by adverfity, he 

 thenceforth condufted himfelf fo as to obtain the good- 

 will of his people ; and fuch was the reputation which he 

 now acquired abroad, that he was elefted emperor of 

 Germany. 



The firft objeft of Sigifmund in his new dignity, was to 

 put an end to various diforders and diffentions which pre- 

 vailed in Germany. He held a conference with pope 

 John XXIII. for the convoking of a council, the principal 

 objeft of which was the termination of the fchifm in the 

 papacy which had long divided the church. He engaged with 

 great zeal in this matter, and at length effefted the affem- 

 bling of a council at Conftance, in 1414, at which he himfelf 

 aflifted. As the oppofition of the Huffites to the doftnnes 



10 "f 



