- 56 - 



positively established. Bacon only carried out oxidation-tests with the 

 object of quantitatively determining a- and /? - phellandrene side by 

 side in the separate oils, in which attempt he did not succeed. It 

 is said that the elemi terpenes contain still a third phellandrene with 

 a higher boiling point, and possessing the following constants: b. p. 175 

 to 1 78 at 760mm., d^ 0,83 75, « D30 o (-f?) 82,4°, n D30O 1,4685, which 

 also yields a nitrite melting at 121 . Other elemi samples from Culion 

 and from the island of Mindanao gave terpen e fractions containing 

 hardly anything except pinene, as was shown by the fact that, when 

 treated with hydrogen chloride, a hydrochloride melting at 125° was 

 obtained. Altogether 90 °/ of all the elemi samples of various origin 

 which Bacon examined were found to contain phellandrene. 



So far as the technical details of the collection of elemi are concerned, 

 it is stated that the best means of cleaning the crude, and often dark 

 and dirty gum, consists in dissolving it in benzene and in freeing 

 the filtered solution from benzene by distillation, as a result of which 

 a pale product of the same scaly structure as elemi remains behind. 

 The residue of resin which is left in the preparation of the oil ap- 

 pears to be suitable for the preparation of lacquers and varnishes, 

 and further experiments are being carried out in this direction. By dry 

 distillation of this residue an apparently valuable resin oil was also obtained. 



Further researches by Bacon had for their object the investigation 

 of the properties of the hydrocarbons obtained from elemi oil, viz., 

 limonene and phellandrene. In the case of the latter the remarkable 

 circumstance was observed that the optical rotation diminished con- 

 siderably under the influence of sunlight; much more so, in fact, than 

 under that of heat. An a-phellandrene, originally recording a v~\- 134,5°, 

 showed only -}- 13 2° after two hours' exposure to sunlight, after 

 8 hours more only -|- 124,7°. Another sample which rotated in the 

 original state-]- 125,5°, showed only-j- 101,5° after a week's exposure. 

 A "/?- phellandrene", originally «p -}~76,7°, became noticeably more 

 viscous in the course of a week and gave only-)- 32,1°. On the other 

 hand, in the same period of time, the rotation of limonene only 

 diminished from -|- 96° to -f- 94,9° ; the change, therefore, being almost 

 negligible. Other investigations related to the conversion of limonene 

 and phellandrene monohydrochloride and -bromide with magnesium 

 and benzaldehyde , in the manner already described 1 ). As noticed 

 at the time, the reaction proceeded abnormally, inasmuch as, when 

 the products of reaction were treated with water, the corresponding 

 dihydroterpenes were formed, along with benzaldehyde and a little 

 benzoin. The same conversion of limonene dihydrochloride produced 

 tetrahydrolimonene. 



x ) Philippine Journ. of sc. 3 (1908), A, 49; Report November 1908, 173. 



