— 46 — 



Romeo 1 ): 3,64 to 4,48%; Rother-): 5,25 to 5,9%; Bruylants ;i ) : 2,86 to 

 6,47%; A. H. Bennett 4 ): 4,3 to 5,2%; Chace 5 ): 4,1 to 7,0%. 



Some years ago we ourselves, working by a method communicated 

 to us by a friend of our firm, but which has not been published, have 

 found warranted pure lemon oils to contain from 4,3 to 7,2 % citral"), 

 but in the course of time we have become convinced that the results 

 obtained by this method, in its original form, may in part have been too 

 high, for after further improving the method we only obtained values 

 fluctuating from about 4 to 5%. 



What has been said above should suffice to show that in view of 

 the far too insufficient degree of reliability of the majority of the various 

 methods of estimation, the guaranteeing of a definite citral-content in 

 lemon oil is a matter of quite subordinate importance, especially because 

 that content is subject to natural variations. Furthermore, it is probable 

 that in pure oils the citral-content does not reach 6 to 7%, as is conspicu- 

 ously stated to be the case by certain firms. In the face of such re- 

 commendations the conviction involuntarily imposes itself that they are 

 only made to mislead buyers. We regard it as wrong to attach special 

 value to a definite and if possible very high citral-content in lemon oil, 

 for inasmuch as this factor varies in pure oils, and only amounts to a 

 few per cent, slight adulterations do not show themselves in the citral- 

 content, while serious adulterations are much more readily detected by 

 the ordinary methods of examination. 



Mandarin Oil from unripe fruits. A sample of oil has been sent 

 to us from the Province of Valencia in Spain, which was pressed from 

 green unripe mandarins (mandarinettes), and in view of the fact that oil 

 from this material was unknown up to the present it may here be briefly 

 described. The oil was of a deep olive-green colour and possessed a 

 pleasant aroma, less delicate, however, than that of oil pressed from ripe 

 mandarins. Its constants also deviated somewhat from those of the 

 latter: d 15 o 0,8665, n D20 o 1,47900, acid v. 0,2, ester v. 17,3, evaporation- 

 residue 8%. Owing to the dark colour it was impossible to read the 

 rotation of the original oil; the angle of rotation of the initial 10% of the 

 distillate was « D + 55°12\ The oil was not completely soluble in 90% alcohol, 

 but it made a clear solution with one half its own vol. a. m. 95% alcohol. 



x ) Tin nuovo metodo di determinazione quantitativa del citral. Messina 1905. Report 

 October 1905, 30. 



2 ) Die Bestimmung, der Aldehyde und Ketone zur Bewertung citherischer Ole. Inaug. 

 Dissert., Dresden 1907; Report October 1907, 120. 



3 ) Bull, de l'Acad. roy. de Belgique (Classe des sciences), Nr. 3, 1907, 217. Annal. de 

 Pharm. 13 (1907), 321; Report October 1907, 122; April 1908, 168. 



*) Analyst 34 (1909), 14; Report April 1909, 110; October 1909, 153. 



5 ) Journ. Americ. chem. Soc. 28 (1906), 1472; Report April 1907, 116; April 1910, 64. 



fi ) Report November 1908, 60. . 



