JUNK

used under the name of pounce, to prevent ink sinking into paper from which writing has been erased. JUNK. A large flat-bottomed ve el, with three masts, and a short bowsprit placed on the starboard bow, used by the Chinese. The masts are supported by two or three shrouds, which at times are all carried on the whidward side; and the fore or main mast carries a sort of lug sail of cane of bamboo. JU'NO. The Latin name of the divinity called by the Greeks Hera CH{»j). She was the sister and consort of Jupiter, and was held to preside over marriage, and protect married women. She was represented as the model of majestic beauty, in royal attire, and attended by her favourite bird the peacock. Her principal temples m Greece were at Samos and Argos. She was also the patrone of Veii, whence she was invited to Rome on the occasion of the last siege of the former city. Ju'no. One of the four small extra-zodiacal planets which circulate between the orbits of Mars and Jupiter. Juno was discovered by Profe or Harding of Lilienthal (near Bremen), on the 22d of September, 1804; Ceres and Pallas having been discovered previously. Juno appears like a star of the eighth or ninth magnitude, and is of a whitish colour, without nebulosity. This planet is distinruished by the great eccentricity of its orbit, exceeding that of any other planet, and amounting to '2578, the semi-axis major being taken as unit. The effect of this eccentricity on the motion of the planet is such, that the half of the orbit which is bisected by the perihelion is described in about half the time in which the other half is described. The sidereal revolution is performed in 1.592'66 mean solar days. The inclination of the orbit to the ecliptic is 13^4' 10"; and the greatest equation of the centre 29° 46' 19". The extreme smallne of the planet renders it impo ible to determine its apparent diameter, and consequently its magnitude, with any degree of certainty. JU'NTA. (Span, an a embly.) A grand Spanish council of state. Besides the a embly of the states or cortes, there wfere two juntas: one which presided over the commerce, the mint, and the mines; and the other forming a board for regulating the tobacco monopoly. The a embling of a junta by Napoleon in 1808, and the part they subsequently played in Spanish history, are sufficiently known to the reader. In England the term junto (evidently of Spanish origin) is used almost synonymously with cabal or faction. JU'PITER. In Mythology, the Latin name of the deity called by the Greeks Zeus {ZivsY it is derived from that word with the addition Pater, Father. He was the son of Saturn, whom he deposed from his throne, and thence became the supreme monarch of gods ^pd men. He married his sister Juno, by whom he had Vulcan; but besides this deity he had a large progeny of gods and demigods by his numerous divine and mortal paramours. The most celebrated of his children were, Minerva, who had no mother, but sprung armed from her father's forehead; Bacchus, the Muses, Venus, Apollo and Diana, Mercurj', Proser pine, Hercules, Perseus, and Minos. The most celebrated Grecian temple of this god was at 01}niipia in Elis, where every fourth year the Olympian games were celebrated in his honour: his most revered oracle was among the oak woods of Dodona in Epirus. The Romans considered Jupiter as especially the patron of their city, in which he accordingly had some splendid temples: that in the capitol was the grandest. Of that dedicated to Jupiter Stator there are still three columns standing. Jupiter was represented as the model of dignity; grave, but mild: he is seated on a throne grasping his sceptre and a thunderbolt, and by his side stands his peculiar bird, tlte eagle. It has been remarked that there is a striking similarity between Jove (from Jovis, gen. of Jupiter), and the Hebrew name of the Supreme Deity, Jehovah. Jui'iTER. In Astronomv, one of the planets, and the largest in the system. The mean diameter of Jupiter Is no le than 87,000 miles, or about eleven times that of the earth; consequently his bulk is about 1300 times greater than that of the earth. The distance of Jupiter from the sun is nearly 490 millions of miles, or about 5i times the radius of the earth's orbit; and he performs his revolution in respect of the stars in 4332 days, 14h. 2m. 8Jsec., which is nearly 12 years. The inclination of the orbit to the plane of the ecliptic was 1° 18' 51" at the beginning of the present century, and undergoes a diminution of about a fourth of a second in a year. " The disc of Jupiter is always observed to be cro ed in one certain direction by dark bands or belts. These belts are, however, by no means alike at all times; they vary in breadth and in situation on the disc (though never in their general direction). They have even been seen broken up, and distributed over the whole face of the planet; but this phenomenon is extremely rare. Branches running out from them, and subdivisions, as well as evident dark spots, like strings of clouds, are by no moans uncommon; and from these, attentively JURY, TRIAL BY. watched, it is concluded that the planet revolves in the surprisingly short period of 9h. 55 m. 50 sec. (sid. time) on an axis perpendicular to the direction of the belts. " The parallelism of the belts to the equator of Jupiter, their occasional variations, and the appearances of spots seen upon them, render it extremely probable that they subsist in the atmosphere of the planet, forming tracts of comparatively clear sky, determined by currents analogous to our trade winds, but of a much more steady and decided character, as might indeed be expected from the immense velocity of its rotation. That it is the comparatively darker body of the planet which appears in the belts is evident from this -that they do not come up in all their strength to the edge of the disc, but fade gradually away Jbefore they reach it." {HerscheVs Astronomy, Cabinet CyclopcBdia, p. 281.) The radius of Jupiter being II times greater than that of the earth, and the rotation on the axis being 2-4 times more rapid, the space pa ed over by a point on the equator of the planet will be 26 times greater than that described by a point of the terrestrial equator in the same time. Hence the centrifugal force is aboiit 26 times greater, and we may therefore conclude that its effect in impre ing a flattened form on the planet will be much greater than takes place with regard to the earth. Now observation shows this to be the case. The disc of Jupiter is evidently not circular, but elliptic, being considerably flattened in the direction of its axis of rotation; and this appearance is no optical illusion, but is authenticated by micrometrical measures, which a ign 15 to 14 as the proportion of the equatorial and polar diameters. This far exceeds the compre ion of the earth, the ratio of the equatorial -to the polar diameter of which is 302 to 301. The annual parallax of Jupiter is le than 12°; consequently the earth, as seen from Jupiter, will never appear at a greater distance than 12° from the sun. The digre ions of Mars will be 17°, those of Venus 8°, and those of Mercury only 4° 16'. An inhabitant of Jupiter would therefore probably be ignorant of the existence of Mercury, which will be almost constantly plunged in the sun's rays, and likewise diminished in splendour, on account of the greater distance. The density of Jupiter is very nearly the same as that of the sun, and about one fourth of the mean density of the earth. The ma of the planet, compared with that of the sun taken as unity, is -000943; but this is suflScient to produce a very sensible perturbation of the motions of some of the other planets. The proportion of light and heat received by Jupiter from the sun, compared with that received by the earth, is as -037 to 1. Jupiter, through the telescope, is observed to be accompanied by four moons or satellites, which revolve about the planet nearly in the plane of its equator, exactly in the same manner as the moon revolves about the earth. Their configuration changes at every instant; they appear to oscillate on each side of the planet, and their rank or order of distance is determined by the extent of their oscillations. In coming between the sun and Jupiter, the satellites throw their shadows on the planet, and produce eclipses of the sun; and when they come to the side of the planet opposite to the sun they are eclipsed in pa ing through the shadow. The beginnings and endings of these eclipses can be observed with great precision; and their observation furnishes the surest means of determining the sidereal and synodic revolutions of the satellites. The same observations also afford a means of determining terrestrial longitudes; and it was by means of them that astronomers discovered and measured the velocity of light. See Planet and JU'RISCONSU'LT. (Juris consult us, learned or skilled in law.) A title given to a cla of Roman lawyers, and commonly denoted bj; the abbreviation ictus. From what we know of the jurisconsults, they appear to have been a different cla from the advocati or causidici who conducted causes, and to have confined themselves to the employment of giving responsa or opinions on cases put to them. (See McTn. de I'Ac. dfs Inscr. vol.xli.) From the recorded opinions of the most learned jurisconsults the Digest, the great work of Just in i an, was chiefly compiled. See Advocate. JU'RISPRU'DENCE. The science of right. (From the Latin words juris prudens, skilled in law.) The term civil jurisprudence is sometimes restricted to the science of the Roman or civil law. For a literally complete list of works on this extensive subject, see Krug's Philosophisches Lexicon, art. " Rechtslehre." JURY-MAST. In Naval affairs, a temp or.ary mast erected in a ship in the room of one that has been carried away by tempest or any other accident. Jury-masts are sometimes erected in a new ship to navigate her down a river, or to a neighbouring port, where her proper masts are prepared for her. JURY, TRIAL BY. Of the origin and progre of this institution, as far as it has been very imperfectly traced by antiquarians, some account has been given in Page 636