PINENES OF THE OILS OF THE GENUS EUCALYPTUS. 205 



allowed to crystallise in the freezing mixture. The crystals from 

 both forms were identical in every respect and melted quite 

 sharply at 103° C. The product from the dextropinene was 

 heated with alcoholic soda and the nitrosoterpene thus formed, 

 when crystallised from alcohol, melted at 128° - 129° 0. 



The hydrates. 



About four or five volumes of the pinenes were agitated for two 

 or three days with one volume of nitric acid (sp. gr. 1-25) added 

 to half its quantity of alcohol ; the solutions were then allowed 

 to slowly evaporate in open vessels. After some days fine crystals 

 were formed in some quantity with both forms. These were 

 rhombic crystals, and when purified by recrystallisation from 

 alcohol, melted at 116° - 117° C. with elimination of water. On 

 melting these terpene hydrates and taking the melting point of the 

 terpenes thus formed, it was found that they both melted at 102° 

 - 103° C. and that they both sublimed in crystals. The terpene 

 hydrate from either form was soluble in boiling water, in alcohol 

 and in ether; both behaved chemically in exactly the same manner 

 in every respect. 



A vapour density determination gave almost the identical 

 figures required for the molecule C 10 H 16 . 



The monohydrochloride was prepared from the dextropinene, 

 this had the odour and appearance of ordinary camphor and melted 

 at 123°- 124° O. 



Crystalline tetrabromides could not be obtained by ordinary 

 methods. 



Polymerisation of the Oil. 



A portion of the crude oil, E. dextropinea from Barber's Creek 

 was treated with a very small quantity of sulphuric acid ; much 

 heat was generated, and the oil was much darkened. After the 

 action was thought to be complete the product was well washed, 

 dried, and distilled. It was then found that polymerisation had 

 taken place, the boiling point of the oil being raised considerably. 

 In the original crude oil from Barber's Creek there was obtained 



