CRYSTALLINE CAMPHOR OF EUCALYPTUS OIL. 103 



Cyuiene is closely connected with the pinenes, and has been shown 

 to contain iso- and not normal propyl. 1 It may be too that 

 dipentene takes some part in this alteration. Eucalyptol, which 

 is identical with cineol, 2 appears not to be either a ketone or an 

 alcohol, as it does not combine with hydroxylamine or phenyl- 

 hydrazine. It is not attacked by sodium nor by benzoyl chloride 

 below 120°. 



The results of this investigation on eudesmol point to a structure 

 allied to that of eucalyptol, but containing two atoms less of 

 hydrogen. The oxygen atom of eucalyptol enters the molecule 

 during the formation of eudesmol, and if cymene be the structure 

 upon which eudesmol is built, then the two added hydrogen atoms 

 enter the molecule at the same time as the oxygen atom. When 

 those Eucalyptus oils which contain a farly large percentage of 

 high boiling constituents are distilled under atmospheric pressure, 

 the fraction boiling above 250° C. almost in every case splits off 

 a portion of water, and it thus appears that water is present in 

 fairly loose chemical combination with the constituents which 

 compose the high boiling portion of the oils. That it is this water, 

 or its elements, that assists in the formation of eucalyptol appears 

 certain, if it is not so, then it is difficult to account for the forma- 

 tion of eucalyptol in those Eucalyptus oils when kept in their 

 crude condition in a closely stoppered bottle, or to account other- 

 wise for the increase in them of from twenty to thirty per cent, 

 of eucalyptol. That the alteration is from higher boiling con- 

 stituents to those boiling at a lower temperature is shown in the 

 analyses given, and this must necessarily be so if eucalyptol is the 

 final product as supposed. It has been shown by the investigation 

 on the oil of E. eugenioides that oxygen is necessary to start this 

 change. That the increase in eucalyptol content means also a 

 diminution of certain of the terpenes has also been shown. 



1 Widman, Ber. xxiv., 439. 



2 The name eucalyptol has been retained in this paper to indicate the 

 precise origin of the material, Eucalyptus oils. It may be that cineol 

 found in the Melaleucas may have a like origin as both genera belong to 

 the N.O. Myrtacese. 



