4<>7 



and also of the Isevo-rotatory pinene of the Eucalypts, although this laevo foriri 

 has, as far as observed, a higher specific rotation. 



Although it had teen assumed that pinenes having right and left 

 rotations were probably present in Eucalyptus oils, yet no proof had previously 

 been forthcoming that this was so. The isolation of the corresponding laevo- 

 rotatory pinene from the oil of E. Icevopinea, E. Wilkinsoniana, and other species 

 shows conclusively that such is the case, and that we have existing in the oils 

 of the Eucalypts two pinenes, one of which is the physical isomeride of the 

 other. In this respect the oils of the Eucalypts differ from those of the 

 Angophoras. 



The two species of Eucalypts here selected, from which these highly 

 rotatory pinenes were obtained, are members of a different group from that to 

 which E. globulus, E. Bridgesiana, &c., belong. The study of the oils of the 

 " Stringy bark " group has been of great assistance in helping to extend the 

 knowledge of the constituents of the oils of the Genus. 



Cineol is present in very small amount in the oils of these two species, 

 being rather more pronounced in that of E. Icevopinea, and it was only possible to 

 detect it with certainty in the portion of the oil distilling at the right temperature. 

 It is not thought that at any time of the year will cineol be found to be much 

 more in evidence, and a determination for cineol by the resorcinol method in 

 the oil of E. dextropinea only gave a return of 6 per cent, in the crude oil. 



The Currawang Creek sample of E. dextropinea gave 63 per cent., boiling 

 between 156 and 162 C., and 25 per cent, more distilling between 162 and 

 172 C. The oil from the Barber's Creek sample, under exactly the same 

 conditions, gave 62 per cent., boiling between 156 and 162- C., and 25 per cent, 

 more between 162 and 172 C. Further investigation showed these two oils to 

 be practically identical, although the Barber's Creek sample was rather more 

 highly dextro-rotatory than that from Currawang Creek, but differences of this 

 character might be expected, because experiments have shown that oils obtained 

 from trees of the same species growing together under exactly similar conditions, 

 have not the same rotations, but differ at times to the extent of a few degrees. 

 Constancy in optical rotation is not observed with Eucalyptus oils, although 

 the variation as a rule only extends to a few degrees. 



The oil from the Rylstone Eucalypt, rectified under exactly similar 

 conditions, gave 60 per cent., distilling between 157 and 164 C., and 28 per 

 cent, more between 164 and 172 C., so that the temperature required to distil 

 the laevo-rotatory pinene was slightly higher than that necessary to distil the 

 dextro-rotatory form. The higher boiling point ; was, however, traceable to the 

 rather larger amount of cineol in the oil of E. Icevopinea. 



The dextro-rotatory pinene. The crude oil of E. dextropinea, from 

 Currawang Creek, gave the following results : 



On rectification, 2 per cent, came over below 156 C.,. this portion 



contained a little acid water and a small quantity of volatile 

 aldehydes. 

 Continuing the distillation : 



63 per cent, distilled between 156-162 C. = first fraction. 



M 162-172 C. = second fraction. 



Specific gravity, first fraction, at 15 C. = 0-8670. 



second fraction ,, = 0-8725. 



crude oil ,, = 0-8758. 



Optical rotation, first fraction ,, D + 33 >:I - 



second fraction ,, a D + 31-7. 



