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active and the inactive form, 1-a-pinene forming by far the greater 

 part. The last named substance was traced by oxidation into active 

 pinonic acid. The spec. rot. of the free acid was about — 65 in a 

 5°/ chloroform solution. Pinonic acid semicarbazone, m. p. 204 . 



The presence of phellandrene was detected in our laboratory as 

 far back as 1897 x ) by means of the nitrite, m. p. 102 . We were 

 also able to determine the presence of /?-phellandrene by oxidation 

 with permanganate. This test yielded a liquid glycol, which was con- 

 verted, by boiling with dilute sulphuric acid, into a hydrated cuminic 

 aldehyde, the semicarbazone of which had a m. p. of 203 to 204 . 



/?-Pinene. 



Oxidation with permanganate with the addition of caustic soda 

 yielded a sparingly soluble sodium salt, the best yield being obtained 

 from the fraction boiling between 165 and 168 . This salt was found 

 to be sodium 1-nopinate. The oil which had remained unaffected 

 by the oxidising process contained, in addition to an intact hydro- 

 carbon, small quantities of nopinone (semicarbazone m. p. 187 to 

 1 88°). The nopinate of sodium which was separated out from the 

 oxidation liquors was recrystallised from water, and the nbpinic acid 

 contained therein liberated. Recrystallised from benzene, the acid was 

 found to have m. p. 126 , Md — 15,88° in an 11,4 per cent, ethereal 

 solution. The nopinate of sodium was again oxidised into nopinone 

 by permanganate with the addition of sulphuric acid. The ketone was 

 dextrorotatory, its semicarbazone melted at 188° and proved to be 

 identical with the similar body from French oil of turpentine and 

 from oil of hyssop. 



It is remarkable that /?-pinene could be detected in this manner 

 in all the fractions, even in those with the highest boiling points. The 

 slight rotation of limonene is therefore mainly due to the presence of 

 this lsevorotatory hydrocarbon in addition to d-limonene. 



7-Terpinene. 



In the course of the process of oxidation with permanganate with 

 the addition of free alkali, all the fractions boiling at 173° and higher 

 yielded, besides nopinic acid, a body which was very sparingly soluble 

 in water. Recrystallised from 25 per cent alcohol, and heated rapidly, 

 it was found to melt at 237°. All the fractions only yielded minute 

 quantities of the substance. The body was identified by the erythritol 

 of y-terpinene, and this result was confirmed by a comparison with 

 erythritol from other sources. 



2 ) Report October 1897, 26. 



