— 88 — 



The proportion of vegetable wax left behind when the extracts were 

 subjected to distillation by steam was the same for the May and October 

 flowers. Its m. p. was not very sharp, moving between 46° and 50°; sap. no. 

 of the wax from the May flowers 80,1, ditto from the October flowers 77,2. 



The reason why the autum flowers contain less oil than the spring 

 flowers is said to be that the average temperature is higher in the spring 

 than towards the end of October and that the circulation of the various 

 constituents of plants is more active at the normal flowering period than 

 at other times. Roure-Bertrand Fils ascribe the difference in the con- 

 stitution of the two oils to the circumstance that the essential oil con- 

 tent of the May flowers is determined by the young shoots, whereas the 

 oil of the October flowers is supplied to them through the maturer branches. 

 The small content of methyl anthranilate in both oils is remarkable, for 

 generally Roure-Bertrand Fils .have found it to be 7°/o, the same figure 

 as has been obersed by Hesse and Zeitschel 1 ). Roure-Bertrand Fils are 

 of opinion that the smallness of the proportion of methyl anthranilate 

 in the two oils under review is accounted for by the exceptionally severe 

 winter which preceded the crop. In determining the proportion of the 

 ester in question it is desirable, in order to spare the other constituents 

 of the oil, to dilute the latter with 6 vols, of ether (not, as suggested by 

 Hesse and Zeitschel 2 ), with two to three vols.) and to precipitate at a 

 temperature of — 4°. For the same reason the filtrate should be well 

 cooled (ice-water). In order to render the excess of sulphuric acid harm- 

 less as quickly as possible, Roure-Bertrand Fils carry out the filtering of 

 the essential oil in a vessel containing a little water, the filtrate being shaken 

 from time to time. When this is done the solutions remain almost colour- 

 less, whereas otherwise they rapidly turn very dark. 



It is a characteristic feature of the oils of neroli extract that they are 

 lasvorotatory, while, when orange flowers are distilled by steam, a dextro- 

 rotatory oil is obtained. The last-named process, therefore, causes an 

 inversion of the direction of optical rotation, at least when the distillation 

 is carried on at atmospheric pressure; for with steam-distillation at di- 

 minished pressure, Roure-Bertrand Fils also obtained a laevorotatory oil 

 (« D — 2°30 f ), of which the odour also agreed closely with that of the 

 extracted oils. An oil from flowers gathered in the autumn of 1909, which 

 had been prepared in the ordinary manner by steam-distillation, was found 

 to have a dextrorotation of +9° 8', the highest value which has thus 

 far been observed in neroli oil. 



In our last Report 3 ) we made mention of an article published by 

 Chapus, according to which Algerian neroli oil contains considerably 



!) Journ. f. prakt. Chem. II. 64 (1901), 245; II. 66 (1902), 481; Report April 1902, 49; 

 Report April 1903, 54. Also compare our investigations detailed in Report October 1903, 49. 



2 ) Berl. Berichte 34 (1901), 297. 



3 ) Report April 1910, 79. 



