lu.'S 



XAXTHIC ACID. 



1020 



fighting, while on each side of the tomb was an armed figure in a 

 quadriga. Other slabs, statues, and sculptured fragments, of a more or 

 less debased style, carry down the illustrations of Lycian art to the 

 period mentioned above. 



(Fellows' Journal, Jcc. : Account of Discoveries in Lycia ; Account 

 of the Ionic Trophy Monument excavated at Xantltus ; and Essay on the 

 tiildtlrc Dates of the Lycian Monument* in the Britith M 'useum ; Scharf, 

 Obserrations on the Sculptures seen on the Monuments of Ancient Lycia; 

 Gerhard, Arrhdol. Zeitur/,l8i5; Official Synopsis of British Museum.) 



XANTHIC ACID. 'Sulphocarborinic acid. EthyldimilphocarlMnic 



acid (0,^0,8, = C U S 4 j C '2o)- Xanthate of potash is formed on 



fronting an alcoholic solution of potash with bisulphide of carbon until 

 all alkaline reaction be neutralised ; the mixture artificially cooled 

 deposits colourless prismatic crystals, which are very soluble in water 

 or alcohol, but insoluble in ether ; dilute hydrochloric acid decomposes 

 them and sets free xanthic acid. 



Xanthic acid ig so named from (aySot, yellow, because it gives a 

 yellow precipitate with salts of copper. It is oily; heavier than, and 

 insoluble in, water; has an acid, astringent, and bitter taste, and 

 pungent odour. Heated to ebullition it is decomposed into alcohol 

 and bisulphide of carbon, and is very inflammable. It strongly 

 reddens litmus paper and decomposes alkaline carbonates with effer- 

 vescence. 



The xanthatei are, with the exception of xanthate of potash, unim- 

 portant. The copper salt, already referred to, seems to be accompanied 

 by a crystallisable compound. Xanthdene (xanthate of ethyl), an oily 

 liquid, is also occasionally formed at the same time, but possibly is a 

 product of the decomposition of the crystalline body. 



XAXTHIC OXIDE. [URIC GROUP.] 



XANTHIN. Tins name has been applied to two distinct bodies, 

 namely, to a colouring matter contained in madder [MADDER, 

 COLOUKI.M; MATTKHS OF] and to the yellow colouring matter of 



The latter is best extracted by treating the sunflower with 



- absolute alcohol ; on cooling, the alcohol deposits the whole of 

 the xanUiiii, which is of a beautiful yellow colour, insoluble in water, 

 but soluble in hot alcohol and water. It is an uncrystalluiable resinous 

 substance. 



XAXTHO-COBALTIA (Co t O,, 5NH,. NO,). An ammoniacal base 

 containing cobalt. It is obtained in the state of sulphate by trans- 

 mitting a rapid current of nitrous acid through an ammoniacal solution 

 of sulphate of cobalt, keeping the liquid alkaline by the occasional 

 addition of ammonia. The sulphate of xanthocobaltia has the formula 

 Co,O,, JXHj, NO,, SSOj + HO. 



The nitrate and chloride have the following formula) : 



Nitrsto . . . Co,O,, 5NH,, NO,, 2.N0 5 +nO 

 Chloride . . . Co.OCl,, SNH,, NO, +IIO 

 [COBALT.] 



XAXTHOCKXAMIDE. [CARBAMIC ACID. Sulphocarbamate of 

 eth,,l.} 



XANTHoI'I'.NIC ACID. [OPIUM, ALKALOIDS OP, Opiammn*.] 



XAKTHOPHYLL. It is well known that in autumn the foliage of 

 rijreet-treea becomes of a bright yellow colour, which, according to 

 Bcrzelius, U owing to the replacement of the green colouring-matter of 

 the leaves, or CMoro/AyU, by a peculiar yellow colouring-matter which 

 he calls Xanthophyll. The properties of this are, that it is a fatty 

 substance of a deep yellow colour, which melts between 100 and 

 120 Fahr. : it is insoluble in water, but dissolves copiously in alcohol 

 and ether ; its solution exposed to air and light is rapidly bleached ; 

 alkalis dissolve it sparingly. 



XAXTHOPICRITK. Xaulktfterlu. A substance contained in the 

 bark of the Xanthoxylum Clara-Jfcrculu, L., employed in the Antilles 

 as a febrifuge. It crystallises in greenish-yellow silky needles, which 

 are bitter and astringent, readily soluble in alcohol, slightly so in 



water, and insoluble in ether. It possesses neither acid nor alkaline 

 qualities. 



XAXTHOPROTEIC ACID (C^H^O,. ?). According to Mulder, 

 this acid is formed when albumen or any other protein compound is 

 digested in nitric acid ; these dissolve with the escape of nitrogen gis, 

 and yield a yellow-coloured solution, while oxalic acid and ammonia 

 are formed. 



Two equivalents of protein, 1 of water, and 2 of nitric acid, yield 3 

 of oxalic acid, 2 of ammonia, and 1 of xanthoproteie acid. After being 

 washed with boiling water, this acid exists as a tasteless orange-yellow 

 powder, which combines with acids as perfectly as with bases ; its 

 compounds with the latter dissolve in water, and give dark-red coloured 

 solutions. 



XANTHORHAMNIN. [CHRYSORHAMNIN.] 



XANTHOXYLENE. [ESSENTIAL OILS ; xanthoxylum-.'] 



XANTHOXYLIN. [ESSENTIAL OILS ; xanthoxylum.] 



XIPHIAS (constellation). [DORADO.] 



XUTHENE. [XANTHIN.] 



XYLENE. [XYLOLE.] 



XYLIDINE. [XYLOLE.] 



XYLITE (C^H^Oj ?j. According to Gmelin, when commercial 

 pyroxylic spirit is submitted to distillation from chloride of calcium, 

 a vapour rises, which condenses into a liquid, which he calls xylite. 



The properties of this substance are, that it strongly resembles 

 alcohol ; its odour is like that of ether and agreeable, and ita taste is 

 empyreumatic ; its specific gravity is 0'816, and its boiling-point about 

 143 Fahr. : it is miscible with water, and burns with a white flame. 

 The density of its vapour was found by experiment to be 2'177; by 

 theory it should be rather lighter. 



A\ ith acids xylite produces ethereal compounds, which have not 

 been minutely examined ; and by partial decomposition it gives rise to 

 xylitic acid, xylite naphtha, xylite rcs/,and xylite oil ; these substances, 

 however, have not hitherto been very particularly subjected to experi- 

 ment, and the whole of these bodies require re-investigation. 



XYI.ITK NAPHTHA. [XYLITE.] 



XYLOIDIN. Pyroxam or nitramidine (C^H^NO^O,,, ?). A sub- 

 stance allied to pyroxylin. [GUN-COTTON.] Starch is dissolved in 

 nitric acid of sp. frr. 15, and the solution immediately diluted with 

 water : a white, tasteless substance is then precipitated which is the 

 body termed pyroxylin. It is insoluble in water, alcohol, or ether, 

 and when heated to 356 Fahr. burns rapidly, after the manner of 

 gun-cotton. It explodes when smartly struck on an anvil by a hammer, 

 but less powerfully than gun-cotton. It also leaves much carbonaceous 

 residue when burnt, and, unlike pyroxylin, is easily soluble in nitric 

 acid. Protosalts of iron reliberate starch from xyloidin. 



XYLOLE (C lfl H 10 ). Xylene. A volatile liquid hydrocarbon homo- 

 logous with benzole, &c., of the series C n H n _. It is one of the 

 constituents of the oily impurities contained in commercial wood- 

 spirit, and which separate on the addition of water. It is purified 

 by agitation with concentrated sulphuric acid and fractional distillation. 



Xylole is a limpid colourless fluid ; boiling point 259 Fahr. Fuming 

 nitric acid converts it into nitro-xylole, a yellow oil heavier than water 

 and of an odour somewhat resembling, but less pleasant than, that of 

 nitrobenzolc. Nordhausen sulphuric acid slowly combines with it and 

 forms colourless, deliquescent, acicular crystals of siJfo-xyloic or 

 xylenyltuiphurotw acid (C 18 H 10 S.,0 ). Nitric acid acts upon the latter 

 compound to form nitro-sulfo-xyloic or nitro-jylcnyliulpliurout acid 



(cjLCHOjs.qA 



Xylidine (C| H M N). This alkaloid much resembles its homologues, 

 tuliiiiline, &c. It is produced by the reaction of nitroxylole and 

 sulphide of ammonium. When pure it is almost colourless, but 

 becomes purple on exposure to air and finally resinifies. It turns red 

 litmus paper blue ; boiling point 416 Fahr. 



XYLORETIN (C^H^O, ?). A fossil resin found in Danish peat. 

 It crystallises in confused prisms, which are insoluble in water, but 

 very soluble in alcohol and ether. 



Yha found iU way into the alphabets of Western Europe through 

 the Liter Latin alphabet from the Greek. The oldest form of the 

 Greek character appears to have had no vertical stroke, but to have 

 been precisely the same an the English or Roman V, so that the small 

 character r differed from the other form only in the usual substitution 

 of a curve for an angle. We have said that the letter Y belonged only 

 to the later Uom.in alphabet. This fact has been already remarked 

 upon under X ; and an argument in confirmation of what is there 

 aascrttd may be drawn from the consideration that the Romans already 

 poeMed in their V the representative of the Greek letter. How then, 

 it may be asked, wa it that they subsequently adopted this letter ? 

 The answer would probably be this that the Greek character had 

 changed its power from the original sound of oo, such as is still repre- 

 MDted by the Italian u, to a sound probably like that of the French u, 

 ARTS A*D SCI. DIV. VOL. VIII. 



or even to a weak '. If we traced the Greek letter Y or V still farther 

 back, we should perhaps arrive at the opinion that it grew itself out of 

 a carelessly written 0. The Hebrew character which corresponds to 

 0, namely, "S , already exhibits the opening above, just as the Hebrew 

 ?3 does, compared with the Greek 0. So too the English often write 

 a capital O without joining the circle at the top. To these considera- 

 tions may be added the fact that the Hebrew alphabet, which ended 

 with a T, contains no other equivalent for the Greek T : and again the 

 Etruscans had but one character, V, without any 0. That the intro- 

 duction of the character Y into Latin words has been carried beyond 

 the proper limit has been already remarked [X] ; and we would add to 

 what has been there said, that in the well-known Medicean Manuscript 

 of Virgil there is something suspicious in the fact that this letter 

 always overtops the other letters in such a manner that the vertical 



3u 



