xt 



XIRCOXIA. 



ZODIAC. 



DM 



!>> yellow YOlauta oU 1-16 



Arom.tir, .crid, toll nin 8-0 



Extractive mlublf in alcohol 0-8S 



Acliluloiu and acrid extractive, inaolublo in alcohol . 10-50 



Cum U-05 



Starch (analoicoai to bauorin) 19-85 



Apothcmc, utractrd bjr potath 26-00 



BaMorin 8-SO 



Woodjr fibre 8-00 



Water 11-90 



103-91 



Morin's analysis yields also acetic acid, acetate of potash, ami 

 sulphur, and a resin insoluble in ether aud oils ; while the ashes give 

 numerous metallic salts and alkaline salts. 



The volatile oil is of a pale yellow, lighter than water ; taste at first 

 mild, then hot. The soft resin, obtained by digesting the alcoholic 

 extract of ginger first in water, then in ether, and evaporating the etherial 

 tincture, is not quite analogous to the principle zinyibcrin , procured by 

 Beral, and by him termed ptpcroitl. This last is got by submitting 

 ginger directly to the action of sulphuric ether. Beral recommends 

 many preparations of this principle, but, except from their smaller 

 bulk, it is difficult to perceive what advantage they possess over 

 common ginger and its preparations. Ginger is an aromatic stimulant 

 of considerable power. The effects are greater on organs with which 

 it comes into direct contact than on remoter ones. Thus, when chewed, 

 it is a powerful sialogiie, and relieves toothache, rheumatism of the 

 jaw, and also relaxed uvula. When received into the stomach, it pro- 

 motes digestion in languid habits, and relieves flatulent colie. Gouty 

 subjects are much benefited by it, and for such persons no form is 

 more beneficial than that of preserved ginger taken at dessert after a 

 mixture of viands. But it has the disadvantage of impairing the 

 flavour of the wine taken at the same time. 



The action of ginger on remote organs is greatest on the mucous 

 membranes. Hence the lungs are markedly excited in the relaxed and 

 snffocative catarrh of old people. The mucous membranes of the 

 urine-genital organs are also excited by it in languid habits. Many 

 feeble females receive much advantage from the domestic preparation 

 termed ginger-tea. Some headaches of a sympathetic kind, originating 

 in irritation of the intestinal canal, are often relieved by it. A poultice 

 of scraped ginger, to which warm water has been added, forms a sub- 

 stitute for a mustard poultice, and often relieves headache when applied 

 to the forehead. Ginger-beer is often a grateful beverage in summer 

 heat, but with some persons it disagrees ; this is owing to the sugar, 

 for if made without it, it agrees with such persons well. Lemon-juice, 

 when taken with sugar, often disagrees, as for example with pancakes. 

 The lemon-juice alone is most wholesome. 



ZIRCOXIA. [ZIRCONIUM.] 



ZIKCONIUM (Zr). A rare metal found in the minerals zircon and 

 hyacinth, which contain the oxide of the metal united with silicic acid. 

 To obtain the metal, the double fluoride of potassium and zirconium 

 is to be strongly heated with potassium ; from the cold residue diluted 

 hydrochloric acid dissolves out everything except pulverulent zir- 

 conium, which must be washed first with solution of chloride of 

 ammonium and then with alcohol. Zirconium has not yet been fused : 

 obtained in the manner just described it presents the appearance of 

 a black powder, which assumes a slight metallic lustre under tin- 

 burnisher and scarcely conducts an electric current. Zirconium in 

 this pulverulent form indicates the properties of the massive metal as 

 little as pulverulent aluminium did those of the latter beautiful metal 

 before it was obtained in malleable masses by Bunsen and Deville. 

 When heated below redness in air or oxygen, zirconium takes fire and 

 burns with a very intense light, producing zirconia. It is also gradually 

 oxidised in boiling water, diluted hydrochloric and sulphuric acids do 

 not act upon it, but hydrofluoric acid dissolves it with evolution of 

 hydrogen. The equivalent of zirconium is 33'C if zirconia be written 

 Zr.O,, but U written ZrO, the equivalent is 22'4. 



Zirconia (Zr,0,, or ZrO.). Zirconium and oxygen form only one 

 compound, zirconia, whicn is obtained by fusing finely-powdered 

 zircon with caustic potash or soda and then dissolving the fused moss 

 in dilute hydrochloric acid. Excess of acid and moisture are expelled 

 by heat, when on the addition of water the chlorides of zirconium 

 aud potassium or sodium are dissolved, leaving insoluble silica ; from 

 this solution excess of ammonia precipitates zirconia as hydrate, which 

 must be washed, dried, and ignited. It then presents the appearance 

 of a white infusible and insoluble powder. The hydrate is gelatinous, 

 insoluble in the caustic alkalies, but readily soluble in. acids, aud 

 sparingly so in carbonate of ammonia. 



Zirconia forms salts with acids, which possess the following 

 characters : They have an astringent taste ; they are precipitated by 

 the caustic alkalies potash and soda, and an excess of them does not 

 redisaolve the precipitate. When boiled with sulphate of potash, a 

 submit of zirconia is formed, and being insoluble subsides. Infusion 

 of galls produces a yellow precipitate, and phosphate of soda a white 

 one : carbonate of zirconia, when recently precipitated, is soluble in 

 bi-carbonate of ammonia and of potash. 



ZO'DIAC (in Greek, i ZifSuucis KVK\OS, "the Zodiac circle") is a 

 name given to a zone of the visible heavens, extending in breadth to 



certain equal distance* on both sides of a great circle of the celestial 

 sphere, In the plane of the earth's orbit produced. This circle, with 

 which the apparent annual path of the sun coincide*, is called the 

 ecliptic ; at present it makes, with the plane of the earth's equator, an 

 angle equal to about 23 27' 35", and it is divided into twelve equal 

 parts, called liyni, which receive their denominations from those of the 

 figures intended to designate the constellations or groups of stars about 

 it Most of the figures being those of animals, the name of zodiac 

 (from (<fSu>, z6ilion, the diminutive of $oy, ;o, " an animal ") 1 

 consequence, been applied to the zone. 



The planes of the orbits of all the planets, when produced to the 

 celestial sphere, are supposed to be comprehended within th< ) 

 of the zodiac, and that breadth is determined by two small > 

 parallel to the plane of the ecliptic. Before the discovery of Ceres, 

 Pallas, and the other asteroids, the greatest inclination of the orbit 

 of a planet to the ecliptic scarcely exceeded 7 degrees, and thciv- 

 fore the breadth of the zodiacal zone was Imagined to be about 16 

 degrees, or 8 degrees on each side northward and southward 

 ecliptic. The orbit of Pallas (that which deviates most from the 

 ecliptic) is inclined about 35 degrees to that plane ; and it might now 

 be understood that the breadth of the zone is about 70 degrees. 



The line in which the plane of the ecliptic intersect* that of the 

 terrestrial equator, being produced indefinitely, cuts the eel 

 sphere in two points diametrically opposite to each other ; and one of 

 these meeting the heavens, in the age of the earliest Greek astronomy, 

 near certain stars forming a constellation to which the figure of a ram 

 (Aries) was assigned, is generally called the first point of Aries. From 

 this point are reckoned, on the ecliptic, the longitudes of celestial 

 bodies; and on the equator, their right ascensions. The twelve 

 parts or signs into which the ecliptic is divided are distinguished by 

 the names of the constellations which, in the age above alluded : 

 within their respective extents in longitude ; and the names both of the 

 signs and constellations are as follow : Aries, Taurus, Gemini, < 

 Leo, Virgo, Libra/Scorpio, Sagittarius, Capricoruux, Aquarius, and 

 Pisces. 



The distribution of all the visible stars into groups or constellations 

 was the first step in laying the foundation of astronomical scieu 

 must have taken place in the earliest ages of the world ; aud tb 

 the highest degree of probability that the zodiacs of all nations have 

 been derived from a common source, though in passing from ono 

 people to another it may be easily conceived that the figures would 

 suffer changes from the vanity or caprice of individuals. Among the 

 ancients, the place of the sun in the zodiac served to regulate the 

 seasons of the year; the representations of the figures associated with 

 the groups of stars were almost constant ornaments of the religious 

 edifices ; and superstition assigned to the regions of space influences on 

 the lives and characters of men depending upon the qualities of the 

 animals or objects which distinguished the constellations in the corre- 

 sponding parts of the celestial sphere. 



The loss of the writings of the ancient Babylonians, and the entiro 

 destruction of their edifices, have deprived the world of every monu- 

 ment by which light might be thrown on the state of astronomy among 

 a people whose priests, according to Strabo, were mostly engaged in 

 the study of the science. In fact, our information respecting it t 

 chiefly of the notices given by Ptolemy concerning a few of their obser- 

 vations, and from the evidence of Ueminus. Diodorus Siculus states 

 (' Biblioth. Histor.,' ii. 30) " that the Babylonians had twelve chid' 

 deities, to each of whom they assigned a month, and one of the so-called 

 twelve animals," by which he means the twelve parts of the zodiac ; 

 and from this it may be inferred that they divided the zodiac into 

 twelve signs. Sextus Empiricus (' Adversus Math.,' lib. v.) makes a 

 like statement, and shows how, by means of a clepsydra, the divinimi 

 was or may have been made. With respect to the astronomical monu- 

 ments which adorned their edifices, a few fragments only of stone, 

 having on them figures which may or may not have been intended as 

 representations of those which distinguish the constellations, have been 

 dug up near Bagdad ; and the most remarkable of these is one having 

 on its face a solar disc accompanied by a serpent : the figure may have 

 designated Ophiuchus, and it is possible that it may have been part of 

 a Chakkcan planisphere. The division of the zodiac into twelve signs 

 may have been originally made for the convenience of distinguishing 

 the portions which the sun passes through in the several months ; aud 

 a division into twenty-eight parts is alluded to by Geminus (Elaayayti 

 fit toa/i/una), which was probably made to denote the space daily 

 described by the moon by her proper motion. The former division 

 was used by the Egyptians, the Greeks, aud by all the civilised nations 

 of Asia; and the latter is found among the Persians, Arabs, Hindus. 

 and Chinese : the twenty-eight parts are called the itativn or ali-.ulu of 

 the moon, because this luminary is in some one of t .lay. 



During the invasion of Egypt by the French, in 1 7!t8, General 1 Jesaix 

 discovered some remarkable sculptures on the ceiling of an apartment 

 in the great temple at Denderah (the ancient Tentyra), ami MM. .loilois 

 and Devilliera almost immediately perceived among them figures 

 similar to those which are traced on celestial globes at the present time. 

 The whole of the astronomical figures are within the circumference of 

 a circle above five feet in diameter ; and the apartment in which they 

 were found is in the upper part of the building : adjoining it is an 

 apartment of equal size, which is open to the sky, the ascent to both 



