The Variation in the Character of Eucalyptus Oils 



Distilled from Trees of Differing Ages 



and Forms of Growth. 



THE data given in the previous article dealing with the comparative constancy 

 of the oil products, only treat with those distilled from general material, and 

 not from individual trees or selected growths. In order, therefore, to determine 

 the variation in amount of constituents in oils from such material that might 

 be expected, the following work was undertaken. 



With the exception of two samples of E. Smithii (f and <?), which were 

 distilled by Mr. D. E. Chalker, of Hill Top, New South Wales, from general 

 material, all were prepared at the Technological Museum, the leaves having been 

 specially collected for the investigation, and with the exception of (e) all were 

 from naturally growing trees. 



The results dealing with the oils of E. Smithii were published in the Proc. 

 Roy. Soc., N.S.W., August, 1915. 



The material worked on is represented by the following stages of growth : 

 (a) Leaves from lopped trees, seven months' growth ; collected May, 1913. 

 (6) L.eaves from lopped trees, fifteen months' growth ; collected May, 1913 



(c) Leaves from seedlings, twelve months' growth ; collected June, 1914. 



(d) Leaves from seedlings two and a half years old ; collected July, 1914. 



(e) Leaves from tree cultivated at Marrickville, near Sydney ; collected 



June, 1915. (Tree, 3^ years old). 



(/) Leaves from general material, partly young ; collected January, 1915. 

 (g) Leaves from general material collected three weeks later than (/). 

 (h~) Leaves from old trees ; collected March, 1913. 



The constants, &c., given by the crude oils from the above material were as 

 follows : 



The cineol was in all cases determined by the resorcinol method, in the 

 redistilled portion of the freshly obtained oils boiling below 190 C. and 

 calculated for the original oil. 



It will be noticed from the above table that the oil from the younger 

 seedlings contained more dextro-rotatory pinene and less cineol than did that 

 from the saplings two to three years old, and that the maximum cineol content 

 was reached in the oil from leaves collected from older trees. This is true also 



