- 46 - 



strong formic acid. For its isolation, the readily volatile constituents 

 were driven over from the reaction mixture with steam. The distillate 

 was then oxidised with dilute permanganate solution in the cold, until 

 no further discoloration could be observed when more chameleon 

 solution was added. Boiling point and oxidation products of the 

 hydrocarbon corresponded with those given above. According to this 

 result it is not very probable that in the foregoing case a reduction 

 has taken place. It would rather seem that the formation of the 

 hydrocarbon must be attributed in both cases to the water-abstracting 

 action of the formic and hydriodic acids at increased temperature: 



The further examination of gingergrass oil has still resulted in the 

 following : 



d-limonene and dipentene. These two terpenes were both detec- 

 ted in the portions boiling between 17 5 and 180 . A fraction of the 

 boiling point 176 to 178 (d i5 o 0,8499, a D -f~4 2 °4 o/ )> distilled over- 

 sodium, formed a nitrosochloride of the melting point 103 to 104 , 

 which was converted on the one hand with benzylamine into a-dipentene- 

 nitrol benzylamine of the melting point 1 1 o°, on the other, with piperidine, 

 into a-dipentene-nitrol piperidide of the melting point 1 53 . The pro- 

 duction of the tetrabromide of the melting point 125 also proved the 

 presence of dipentene. We were also able, on the repeated formation 

 of the nitrosochloride from a fraction of the melting point 17 8° to 180 

 ( a i> -j-43° S 2 ')y to identify limonene with the help of its a-piperidine 

 and a-benzylamine derivatives of the same melting point 93 °. 



Aldehyde C 10 H 16 O. The oil portions passing over above the 

 boiling point of the terpenes were found to contain small quantities 

 of an aldehyde, when fuchsin sulphurous acid or sodium bisulphite 

 liquor were added. In order to obtain this aldehyde, the fractions 

 boiling between 8o° and 90 (6 mm. pressure) were shaken for a pro- 

 longed time with bisulphite liquor, and the double compound separat- 

 ing off as a slimy mass was removed from the oil by absorption. 

 From this bisulphite compound purified by repeated washing with 

 alcohol and ether, the aldehyde was liberated by heating with soda 

 solution, driven off with steam, and fractionated in vacuo. It represents 

 a colourless oil of the following properties: 



boiling point 76 to 78 (5 mm. pressure), 22 1° to 224 (754 mm. 

 pressure); d 15 o 0,9351; « D ±o°; n D20 o 1,47348. 



It has a peculiar, not unpleasant odour, which reminds both of 

 oenanthic aldehyde and of citronellal. We produced the following 

 derivatives: the semicarbazone of the melting point 169 to 170 ; the 

 semioxamazone of the melting point 244°to245°, the phenylhydrazone 

 of the melting point 63 °, the /?-naphthocinchoninic acid of the melting 

 point 26 1 °, and the oxime of the melting point 11 5 to 11 6°. The 



