I U P I T E R. 



ftrength in battle, Mars. In procefs of time lliey ufed dif- 

 ferent repiefentatlons of this Jupiter, &c. and conlidered 

 lliem, vulgarly at leail, as fo many different perlons. They 

 afterwards regarded each of tliem in different views : e. g. 

 the Jupiter that (howered down blefTings, was called the 

 KmJ Jupiter: and when punifning, the Tirrible Jupiter. 

 There was alfo one Jupiter for Europe, and another for 

 Africa ; ard in Europe, there was one great Jupiter v.ho 

 was the particular friend of the Athenians, and another v.ho 

 ^as the fpeclal proteftor of the Romans : nay, there was 

 fcarcely a town or hamlet perhaps, in Italy, that had not a 

 Jnpiter of its own ; and the Jupiter of Terracina or Jupiter 

 WiKxur, reprefentcc- in medals as young and beardlels, with 

 rays round his head, more rcfcmblcd Apollo than the great 

 J .'piter at the Capitol. In this way Jupiter at length had 

 temples and different characters almoil every where : at 

 Carthage, he was called Ammon ; in Egypt, Serapis ; at 

 Athens, the great Jupiter was the Olympian Jiipiter ; and 

 at Rome, the grcatcll Jupiter was the Capitoline Jupiter, 

 ■who was the guardian and benefactor of the Romans, and 

 whom they called the bell and greatefl Jupiter, " Jupiter 

 optimus maximus." The figure of this Jupiter was repre- 

 fented in his chief temple or. the Capitoline hill, as fitting 

 «n a turule chair, witii the fulmen or thunder, or rather 

 lightning, in one hand, and a fceptre in the other. This 

 fulmcn in the figures of the old artifts was always adapted 

 to the charafter under which they were to reprefent Jupiter. 

 If his appearance was to be mild and calm, they gave him 

 the conic fulmcn or bundle of flames wreathed clofe to- 

 gether, held down in his hand. When punifhing, he holds 

 tip the fame figure, with two tranlverfe darts of lightning, 

 fometimes with wmgs added to each fide of it, to denote its 

 fwiftnefs: this was called by the poets, the three-forked 

 bolt of Jove : and when he was going to do fome exemplary 

 execution, they put in his hand a handful of flames, all let 

 loofe in their utmoft fury ; and fometimes filled both his 

 hands with flames. The fupcriority of Jupiter was prin- 

 cipally manifefted in that air of majefly which the ancient 

 artifts endeavoured to exprefs in his countenance : particular 

 *tention was paid to the head of hair, the eye-brows, and 

 the beard. There are feveral heads of the mild Jupiter on 

 ancient fcals, where his face has a mixture of dignity and 

 eafe in it, admirably defcriheJ by Virgil, JEn. i. v. 2j6. 

 The ftatues of the Terrible Jupiter were generally of black 

 marble, as thofe of the former were of white : the one fitting 

 with an air of tranquillity ; the other Handing, more or lefs 

 difturbed. The face of the one is pacific and fercne ; of the 

 other angry or clouded. -On the heads of the one tlie hair 

 is regular and compofed ; in the other, it is fo difcompt^fed, 

 that it falls half-way down the foreltead. The face of the 

 Jupiter Tfjtians refembles that of the Terrible Jupiter : he 

 J8 reprefented on gems and medals as holding up the triple 

 bolt in his right hand, and Handing in a chariot, which 

 feems to be whirled on impetuoully by four horfes. Thus 

 he is alfo deferibed by the poets. Ovid. Deian. Here. 

 V. 28. Horace, lib. i. od. 34. v. 8. Jupiter, as the intelli- 

 gence, prefiding over a fingle planet, is reprefented only in 

 a chariot and pair : on all other occafions, if reprefented in 

 a chariot, he is always drawn by four horfes. Jupiter is 

 well known as the chief ruler of the air, whofe particular 

 province was to direft the rains, the thunders, and the llglit- 

 nings. As the difpenfe* of rain, he was called Jupiter 

 Pluvius ; under which charafter he is exhibited feated in the 

 clouds, holding up his right hand, or extending his arms 

 almoft. in a llraight line each way, .and pouring a dream of hail 

 and rain from his right hand on the earth ; whilft the fulmen 

 is held down in his left. The wings tliat are given to liim 



relate to his charafter of prefiding over the air : his hair am! 

 beard in the Antonine pillar are all fpread down by the rain, 

 which defcends in a flieet from him, and falls for the re- 

 frefiiment of the Romans ; wiiilft their enemies are repre- 

 fented as ftruck with the lightnings, and lying dead at their 

 feet. Spence's Polymetis, p. 46. 1S2, and 21", &c. 



JupiTf.n, in j4jlrotiomy, the largeft of the planets of the 

 folar fyftem ; his diameter being 1 1 times greater than that 

 of the earth, or 89,170 Engliih miles. Its revolution on its 

 axis is performed in 9 hours, 55 minutes, and 37 feconds. 

 This planet moves from weft to eaft in a period of 1 1 ye.ars, 

 3 iS days, 14 hours, 27 minutes, 10.7 feconds. Its fynodical 

 revolution is about 399 days. Before its oppofition with the 

 fun, and at about 115- from it, its motion becomes retro- 

 grade, and its velocity continually augments till the moment 

 of oppofition, after w hich it diininifhes, and when at about 

 I I J- from the fun, its motion changes from retrograde to 

 direft. The duration of this retrograde motion is about 121 

 days, and the arc of retrogradation about 10 degrees : and 

 it may be obferved as a general rule with, the fuperior 

 planets, that the farther they are from the fun, the lefs is 

 their arc of retrogradation ; but the longer time, is taken in 

 defcribing it, for were the dillance of planets indefinitely 

 great, the arc of retrogradation would be extremely fmall, 

 and its retrograde motion would laft half a year, refembling 

 the effeft of parallax of a fixed liar, if ever this Ihould be ren- 

 dered fenfible to our inllruments. 



Jupiter is, next to Venus, the mofl brilliant of the planets, 

 and fometimes even furpaffes it in brightnefs. Its apparent 

 diameter is greater at the oppofitions, and is then equal to 

 nearly 4S" ; its mean equatorial diameter is eftimated at 38.8". 

 Its figure is an oblate fpheroid, the proportion of its equa- 

 torial to its polar axis being about 1410 13. La Place from 

 theory deduces this proportion to be 1,000,000 to 9,286,922, 

 a refult obtained from computing the effecl of the equa- 

 torial regions of the planet in difturbing the nodes of the fa- 

 tellites. Almoil every perfon is fufficiently acquainted with 

 the telefcopic appearance of Jupiter, to know that its fnrface 

 IS remarkable for being always covered with u number of 

 belts or ilripes of various Ihades. Thcfe appearances differ 

 much at different times, and even at the fame time in tele- 

 fcope? of different powers. Ufually thefe belts feem to be of 

 an uniform tint ; but in very favourable weather, they fome- 

 times appear to confift of a number of curved lines, like the 

 ilrokesof anengraving. Fi^s. T43, 144, 145, 146. PlauXYl. 

 yljlronomf, reprefent four views of this planet, as given by 

 j5r. Herfchel and Mr. Schroeter. 



Thefe belts were firft obferved at N.iplcs by Zuppi and 

 Bartoli, two Jefuits ; and about the year 1660, they were 

 obferved by Campani, with refracting telefcopes of his own 

 conftruflion, and not much inferior in diflintfnefs to thofe 

 of th.e prefent day ; the great modern improvement in re- 

 fradting telefcopes, coniiilmg rather in the reduftion of their 

 fize tlian in the iccreafe of their magnifying power. 



Jupiter is accompanied by four fatellites, which were dif- 

 covered by Galileo, the Sth of January 1610. He at firit 

 took them for telefcopic fixed ftars ; but continued obferv- 

 ation foon convinced him that they really accompanied the 

 planet. The relative fituation of thefe fmall bodies changes 

 at every inllant : they dfcillate on each fide the planet, and 

 ii is by the extent of thefe ofcillations that the rank of thefe 

 fatellites is determined ; that being called the firft fatelhte, 

 whofe ofcillation is the leaft. They are fometimes feen to 

 pafs over the difc of the planet, and projeft a fhadow in the 

 form of a well-defined black fpot, which then defcribes a 

 cherd of this difc. 



J I. piter and his fatellites, therefore, are opaque bodies, 

 5 enlightened 



