- 38 - 



When hydrating the same fraction by means of glacial acetic acid, 

 a yellowish oil was formed which had the odour of isobornyl acetate, 

 and passed over at 12 mm. pressure between 62 and 108 (the bulk 

 at 6 5 ). On saponifying the oil portions passing over above 95 

 with alcoholic potash, and treating the saponification product with 

 water vapour, a colourless crystalline mass was obtained, which pos- 

 sessed the odour of isoborneol, and which after being recrystallised 

 4 to 5 times from petroleum ether, melted at 208 to 208,5°. The 

 melting point of the isoborneol could not be raised further. 



Phellandrene. Phellandrene was detected in a fraction of the 

 following constants: — di 5>5 o 0,8733, « D -{-34° 34', n D 22,9° 1,47186, 

 boiling point 49,2 to 55° (7 mm. pressure). 



The crude nitrite of the phellandrene obtained in a rather low 

 yield, was freed from the coarsest impurities by trituration with a 

 cold mixture of methyl alcohol and ether, and crystallised from acetic 

 ester. Frequent repetition of the crystallisation led to the a -nitrite 

 of a-phellandrene, which was obtained in an approximately pure state 

 in fine colourless needles of the melting point 114° (slowly heated) 

 or 1 19° (rapidly heated). The specific rotation of this nitrite in 

 chloroform solution was ascertained as [a] D — 133,4°. 



From the mother liquors of the crystallisation of the a -nitrite 

 there was obtained, by precipitating with 60 per cent, alcohol and 

 dissolving in acetic ester, after repeating this operation several times, 

 the y8-nitrite of a-phellandrene of the melting point 103 to 104°, in 

 small needles, grouped in the form of stars, and in a not very pure 

 condition. But it was at any rate possible to determine that the 

 character of the specific rotation of this nitrite (in chloroform solution) 

 was positive (found [«] D -(-16,3°). 



Dipentene. Dipentene 1 ) was detected in fennel oil by brominating 

 a fraction with the following properties: — di5o 0,8607, «p -\~37° 25', 

 boiling point 63 to 67° (16 mm. pressure), boiling point 177,5 to 

 180,5° at 74-8,5 mm. pressure. 



The dipentene tetrabromide melted after recrystallisation from 

 methyl alcohol and subsequently from acetic ester at 124 to 125 . 



Absence of cymene. For the test for cymene, which, according 

 to Tardy 2 ) is present in French fennel oil, we employed a fraction 

 whose constants were as follows: — boiling point 176,2 to 180,5° 

 (762 mm. pressure), « D -f- 23° 56', n D23 o 1,47422. 



First of all this fraction was oxidised with cold 1 per cent, 

 permanganate solution. In order to remove from this fraction any 

 fenchone which may at the same time be present, and which cannot 



*) Comp. Report April 1890, 20. 



2 ) Bull. Soc. Chim. III. 17 (1897), 690. 



