120 AURANTIACEiE. 



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the ecaelle a pique r are mobile liquids of a faint yellow colour, of ex- 

 quisite fragrance and bitterish aromatic taste. 



The different specimens which we have examined are readily niis- 

 cible with bisulphide of carbon, but dissolve sparingly in spirit of Avine 

 (0-830). An equal weight of the oil and of spirit of wine forms a 

 turbid mixture. No peculiar coloration is produced by mixture with 

 perchloride of iron. 



The oils are dextrogyre, but differ in their rotatory poAver, as maybe 

 illustrated by the following results, which wc obtained by examin- 

 ing them in a column 50 millimetres long in the polaristrobometer of 

 Wild. The oil of Signori Panuccio/ due to the sponge-process (p. 

 118, note 2), deviated 20-9^ that of Monsieur Medecin (Essence cU 

 Citron an zeste) obtained by the ^cuelle a piqiier deviated 33'4" and 

 his distilled oil 28•3^ 



Chemical Composition — The prevailing portion o£ most essential 

 oils of the AiLvantiacecB agrees with the formula C^°H'' ; the differ- 

 ences which they exhibit chiefly concern their optical properties, 

 odour, and colour. The boiling point mostly varies from about 170' 

 to_ 180° C, the sp. gr. between 0-83 and O'SS. These oils are a 

 mixture of isomeric hydrocarbons, and also contain a small amount 

 of cpnene, C''W\ and of oxygenated oils,- not yet well known; 

 of these we may infer the presence either from analytical results 

 or simply from the fact that the crude oils are altered by metallic 

 sodnmi. If they are purified by repeated rectification over that 

 metal, they are finally no longer altered by it. Oils thus purifiefl 

 cease to possess their original fragrance, and often resemble oil ot 

 turpentine, with which they agree in composition and general 

 chemical behaviour. ^^ 



As to essential oil of lemons, its chief constituent is the terpene, C"ff - 

 which, like oil of turpentine, easily yields crystals of terpin, C^"H^"30H . 

 Ihere is further present, according to Tilden (1879) another hydro- 

 carbon C'«H'«, which already boil? at 1G0° C, whereas the foregoing 

 bods at 176 C. Lastly a small amount of cymcne and of a compound 

 acetic ether, C2H^'0(C'"H-0), would appear to occur also in oil ot 

 '""^Tr^wrr^r ^^"'"^^ ^^^ ^^ ^^mous already yields the crystalhiie com- 

 pound C"Hio + 2HC1, when saturated with anhydrous hydrochloric ga^- 

 whereas by the same treatment oil of turpentine affords the solid com- 

 pound CHI*' + HCl. 



Essential oil of lemons (not the distilled) when long kept deposits 

 a greasy mass, from which we have obtained small crystals apparentl} 

 ot JJergaptene (p. 123). 



Commerce-Essence of lemons is shipped chiefly from Me'^sina 

 and Palermo, packed in copper bottles called in Italian mTniere i^r^d u) 

 bngh,^ druggists "jars," holding 2.5 to 50 kilo, or more ; sometim 

 tm bottles of smaller size. The quantity of essences of lemon oi 

 ')^1 -of T* exported from Sicily in 1871 was 368,800 lb., valu. 

 xi'i-*,.->.0, of which about two-thirds were shipped to England. 



ons 



esin 

 angc 



fcS f ±u?, 'If'^^^- We have i Consul Dennis, On the ComMVcefcJ 

 15th June T87'>-D H °^" Mentono, H.M. Consuls. No. 4. 1873. 



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