OLEUM BERGAMOTT^. 123 



extraction it gradually deposits a quantity of white greasy matter 

 (bergaptene), which, after having been exhausted as much as possible 

 by pressure, is finally subjected to distillation with water in order to 

 separate the essential oil it still contains. 



The fruits from which the essence has been extracted are submitted 

 to pressure, and the juice, which is much inferior in acidity to lemon 

 juice, is concentrated and sold for the manufacture of citric acid. 

 F'inally, the residue from which both essence and juice have been 

 removed, is consumed as food by oxen. 



Description ^ — Essential oil of bergamot is a thin and mobile fluid 

 of peculiar and very fragnant odour, bitterish taste, and slightly acid 

 reaction. It has a pale greenish yellow tint, due to traces of chloro- 

 phyll, as may be shown by the spectroscope. Its sp. gr. is 086 to 0*88; 

 its boiling point varies from 183'' to 195° C. 



The oil is miscible with spirit of wine (083 sp. gr.), absolute alcohol, 

 as well as with crystallizable acetic acid. Four parts dissolve clearly 

 one part of bisulphide of carbon, but the solution becomes turbid if a 

 larger proportion of the latter is added. Bisulphide of carbon itself 

 is incapable of dissolving clearly any appreciable quantity of the oil. 

 A mixture of 10 drops of the oil, 50 drops of bisulphide of carbon and 

 one of strong sulphuric acid has an intense yellow hue. Perchloride of 

 iron imparts to bergamot oil dissolved in alcohol a dingy brown 

 colour. 



Panuccio's oil of bergamot examined in the same way as that of 

 lemon (p. 120) deviates 7° to the right, and has therefore a dextrogyre 

 power very inferior to that of other oils of the same class.^ But it 

 probably varies in this respect, for commercial specimens which we 

 iudged to be of good quality de\'iated from C"8° to 104° to the right. 



Chemical Composition — If essential oil of bergamot is submitted 

 to rectification, the portions that successively distill over do not accord 

 in rotatory power or in boiling point, a fact which proves it to be a 

 mixture of several oils, as is further confirmed by analysis. It appears 

 to consist of hydrocarbons, C^"H^^ and their hydrates, neither of which 

 have as yet been satisfactorily isolated. Oil of bergamot, like that of 

 turpentine, yields crystals of the composition C^^^ff "^ + SH^O, if 8 parts 

 are allowed to stand some weeks with 1 part of spirit of wine, 2 of 

 nitric acid (sp. gr. 1*2) and 10 of water, the mixture being frequently 

 shaken. No solid compound is produced by saturating the oil with 

 anhydrous hydrochloric gas. 



The greasy matter that is deposited from oil of bergamot soon after 

 its extraction, and in small quantity is often noticeable in that of 

 commerce, is called Bergaptene or Bergamot Camphor. We have ob- 

 tained it in fine, white, acicular crystals, neutral and inodorous, by 

 repeated solution in spirit of wine. Its composition according to the 

 analysis of Mulder (1887) and of Ohme (1839) answers to the formula 

 C'H^O^, which in our opinion requires further investigation. Crystal- 

 lized bergaptene is abundantly soluble in chloroform, ether, or 



* The characters are taken from some at Keggio and also large cultivators of the 



Essence of Bergamot presented to one of us bergamot orange. 

 (15 May 1872) as a type-sample by Messrs. ' See however Oleum Neroli, p. 127. 



G. Panuccioefigli, manufacturers of essences 



