Page:Cyclopaedia, Chambers - Volume 2.djvu/55

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Month the Dog-Days begin. The French call this the Month of Red^Frms, and with Reafon, fays Quhmnie, be- caufe they are then in their height. On the 17th Day of this Monih, according to Hippocrates and Pliny, the Dog- Srar rifes, the Sea boils, Wine turns, Dogs go mad, the liilc is increafed and irritated,' and all Animals decline and languish, &c. The word is derived from the Latin Julius, the Sirname of C. Qefar the Dictator, who was born in it. Mark Anthony firft gave it this Name 3 before, it was called Quintilis, as being the fifth Month of the Year, in the old Raman Calendar eitabliflied by Romulus, which begun in the Month of March. For the fame reafon Au- «i>ji was called Sextilis, and September, OBober, November, and December flill retain the Name of their firft Rank,

Qu<£ fequitur, Numero turba notata'fuo. Ovid. Faft.

JUNCTURE, is any kind of Joint, or doling of two Bodies.

JUInE, the fixth Month of the Year, when the Sun enters the Sign of Cancer. In this Month is the Summer Solitice. The word comes from the Latin Junius, which fome derive <? Junone. Ovid % in the 6th of his Faftl t makes the Goddcfs fay,

Junius a noftro Nomine Nomen habet.

Others rather derive it a Junioribus, this being for young People, as the Month of May was for old ones.

Junius eft Juvenum qui fuit ante Senv.m.

JUNIPER-BERRIES, the Fruit of a Shrub of" the fame Name 5 much ufed in Medicine. Etmuller had a vaft Opinion of them, and thought they deferved a whole Treatife to be wrote of them. The Rob (a Form of Medicine now out of ufe) made of the exprcfled Juice of the Green Berries, has been called thcTheriaca Germa- nomm ■■, fo much have they been in elteem amongfl: them for anti-pelHlential Qualities. They are certainly carmi- native, but their molt remarkable Properties are in fcour- jng the Vifcera, and particularly the Reins and Urinary Tallages, as all of the Turpentine-kind do. The Wood of this Shrub is alfo of considerable Ufe in .Phyfic, it iireng- thens the Stomach, expels Wind, clears the Lungs, pro- vokes the Menfes, and removes Obftru&ions of the Vifce- ra. It is further faid to be Sudorific, Cephalic, and Hyfle- ric. From it they draw a Spirit, a Tincture, an Elixir, Ex- tract, and a Ratifia. 'Tis faid it will kit an hundred Years without corrupting 5 and the Chymifts add, that a Coal of Junifer, covered with Allies of the fame kind, will keep lire an entire Year.

JUNTA, an AfTembly, Council, or Society, of feve- ral Perfons meeting for the Difpatch of any Buiinefs. This Term is particularly in ufe in thcSpanifi and Portu- guefe Affairs. On the Death of Charles II. King of Spain, the Kingdom was governed, during the Abfence of Phi- lip V. by a Junta. In Portugal they have three confide- rable Junta's, the Junta of Commerce, that of the three Eftates, 'and that of Tobacco. The fir ft was cftablimed by King John IV. this is a Council of Marine. Thefame King affemblcd the States of his Kingdom to create the Tribunal of the Junta of the three Eftates. K.-Fete>-II. created the Junta of Tobacco in 1675, it confiits of aPre- fident and fix Counfellors.

Junta was the Name of a Society of Bookfellers or Printers at Venice, who published many beautiful and cor- rect Editions of Books, which llill go by the Name of Junta's.

IVORY, the Tooth or Tusk of an Elephant growing oneach fide of his Trunk, in form of an Horn. Ivory is much elkem'd for its Colour, its Polifh, and the Finenefs of its Grain when wrought. Diofcorides fays, that by boil- ing it the fpace of fix hours with the Root of Mandrago- ras, it becomes fo foft and tradable, that one may ma- nage it as hepleafes. The Ivory of the Ifle of Ceylon and that of thcllleof Achem have this Peculiarity, that they never become yellow, as that of the Terra-firma and Eaji- htdiesdoes ; on which account 'tis much dearer.

Black Ivory is no more than Ivory burnt, and drawn into a Leaf when it is become black. It is ground with Wa- ter, and made up into little Cakes or Troches, ufed by the Painters.

JUPITER, one of the feven Planets: its Character is %. Its Orbit is fituate between Saturn and tdirs. It has a Rotation round its own Axis in 9 Hours, 55 Minutes 5 and a periodical Revolution round the Sun in 4332 Days, 12 Hours. It is the biggeft of all the Planets. Its Diameter to that of the Sun appears, by Agronomical Obfervations, to be as 1077 is to iccco, to that of Saturn as 1077 to 889, to that of the Earth as 1077 to 104.. The Force of Gra- vity on its Surface is to that on the Surface of the Sun as

IT

<as 797,15 to 554,:

797JS 'sto rccco, to that or Saturn &. , to that of the Earth as 79;, 1 5 10407,832. The Dcnfitl ot its Matter is to that of the Sun as 7404 to lecoo, to that ot &t»ro as 7404 to (foil, to that of the Earth as' 7404 to 39z 1. The Quantity of Matter contained irt its Body is to that of the Sun as 9,248 to iooog, to that of Saturn as?, 248 to 4,22?, to that of the Earth as 9 -48 to 0,0044. The mean Diiianceof Suiter -from the Sun is 5201 of thofe Parts, whereof the mean Diftance of the Earth from the Sun is 1000, cho' Kepler makes it 519* of thofe Parts. M. Cajfmi calculates Jupiter's mean Diilance from the Earth to be 1 1 5,000 Semi-Diameters of the Earth. Gregory computes the Diflar.ce of Jup iter from the Sun to be above five times as great as that of the Earth from the Sun ; whence he gathers, that the Diameter of the Sun, to an Eye placed in Jupiter, would not be a fifth part of what it appeals to us ; and therefore his Disk would be twenty-five times lefs, and his Light and Heat in thfi fame Proportion. The Inclination of Jupiter's Otbir, that is, the Angle formed by the Plane of its Orbit, with the Plane of the Ecliptic, is 1 Deg. 20 Min. His Eccentricity is 250 ; arid Huygens computes his Surface to be four hun- dred times aslargc as that of ourEarth. See Solar Syflem.

Jupiter is one of the fuperior Planets, that is, one of the three above the Sun. Hence it has no Parallax, its Di- ilance from the Earth being too great, to have any fenfi- ble Proportion to the Diameter of the Earth. Thought it be the grcateft of the Planets, yet its Revolution about its Axis is the fwiftett. Its Polar Axis is obferved to be ftlorter than its Equatorial Diameter ; and Sir I. Neiston determines the Difference to be as 8 to 9. So that its Figure is a Spheroid, and the Swiftnefs of its Rotation occafions this Spheroidifm to be more fcnfible than that of any other of the Planets. Jupiter appears almoft as large as Venus, but is not altogether fo bright. He is eclips'd by the Moon, by the Sun, and even by Mars, Hevelius obferved Jupiter's Diameter 7 Inches, having In- equalities like the Moon. He has three Appendages, call'd Zones, or Belts, which Sir I. Newton thinks are form'd in his Atmofphere. In thefe are feveral Macule, or Spots ; from whole Motion, the Motion of Jupiter round its Axis is faid to have been firft determined. The Dif- covery of this is controvered between Euftachio, P. Goth- nies, Cajfmi, and Campani.

The four little Stars, or Moons, which move round Ju- piter, were firft difcover'd by Galileo, who call'd them the rljira de MeHicis i but we the Satellites of Jupiter. Cuffim obferved, that the firft or innermoft of thefe Satellites was five Semi-diameters of Jupiter diftant from Jupiter it- felf, and made its Revolution in 1 Day, 18 Hours, and 32 Minutes. The fecond, which is fomewhat greater, he found 8 Diameters diftant from Jupiter, and its Revolution 3 Days, 13 Hours, and 12 Minutes. The third, which is the greatcft of all, is diftant from Jupiter 13 Semi-diame- ters, and finiihes its Courfe in 7 Days, 3 Hours, and 50 Minutes. The laft, which is the leal! of all, is diftant from Jupiter 23 Semi-diameters ; its Period is i<f Days, iS Hours, and 9 Minutes. Thefe four Moons mail make a very pleafing Spectacle to the Inhabitants of Jupiter, if it be true there are any; for fometimes they rife all toge- ther 5 fometimes they are all together in the Meridian; ranged one under another; and fometimes all appear in' the Horizon, and frequently undergo Eclipfes ; the Ob- fervations whereof are found of efpecial Ufe in deter- mining the Longitude. Cajfim has made Tables for calcu- lating the Immerfions and Emerfions of Jupiter's firft Sa- tellite.

The Day and Night are of the fame Length in Jupiter all over his Surface, viz. five Hours each ; the Axis of his Diurnal Rotation being nearly at right Angles to the Plane of his Annual Orbit. Though there are four pri- mary Planets below Jupiter, yet an Eye placed on his Sutface would never perceive any of them, except Sa- lurn; unle fs, perhaps, as Spots pafling over the Sun's Disk, when they happen to come between the Eye and the Sun. The Parallax of the Sun, view'd from Jupiter, wilt fcarce be fcnfible, no more than that of Saturn 5 neither being much above 20 Seconds ; fo that the Sun's apparent Diameter in Jupiter will not be above fix Minutes, The outermoft of Jupiter's Satellites will appear almoft as big astheMoon doestous, •viz. five times the Diameter, and 25 times the Disk of the Sun. Dr. Gregory adds, that an. Aftronomer in Jupiter would eafily diftinguifh two kinds of Planets, four nearer him, viz. the Satellites, and two, viz. the Sun and Saturn, more remote. The former, however,) will fall vaftly (hort of the Sun in Brightnefs, notwithfiand- ing the great Difproportion in the Diftances and apparent Magnitudes. From thofe four different Moons, the Inhabi- tants of Jupiter will have four different kinds of Months; and the Number of Moons in their Year will hot be lefs than 4500. Thefe Moons are eclips'd as often as, being iri- oppofition to the Sun, they fall within the Shadovv of "Ju- piter 5