^<-^> Jo 



Commercial and scientific notes on essential oils. 21 



of water). Starting from Tiemann's work 1 ) the author shows that, by shaking for 2 or 

 3 hours, the main bulk of the citral or of the aldehydes present in addition to citral 

 can be removed with the aid of this solution from genuine, as well as from adulterated, 

 lemon oil. In examining the separate fractions of the lemon oil samples he noticed 

 that the differences found in the values of the citral content, before and after the 

 treatment with bisulphite, were continuously increasing up to the eighth fraction. With 

 the ninth fraction the difference became much smaller again, which Guido regards as an 

 indication that the higher aldehydes had accummulated in this fraction. The author then 

 compares the values for the genuine and for the adulterated oils and for the respective 

 fractions in their variations and he arrives at the conclusion that the method which he 

 had outlined and which is based upon the determination of the citral content of the 

 separate fraction would also furnish the basis for an exact evaluation of lemon oils. 



Mandarin Oil. — Although very high prices were paid last autumn for the fruit on 

 the tree, the harvest seems to have been favourable, for the prices of mandarin oil 

 which culminated by the end of April with 197 lire have since then been on a steady 

 decline. At the present time the value of the article is about 80 lire, the demand 

 being very small. 



Orange Oil, Bitter. — This article was much neglected during the past six months 

 and the prices dropped from about 90 lire in May gradually down to 28 lire. Buyers of 

 larger quantities were absent since people were naturally waiting for the advantageous 

 moment which, in our opinion, does not appear to have come yet. 



Orange Oil, Sweet. — A glance at the table of prices on page 17 will show that 

 this article, which likewise had reached its highest price of 185 lire in May of last 

 year, also suffered from the general drop of prices, indicating that it was not simply 

 the scarcity of the fruit available from the last harvest, but that the speculative policy 

 of certain traders was also responsible for the high quotations. For some months 

 already the product has completely been neglected, and the prices are down to 40 lire. 

 In January of this year only 2500 kg. were exported, that is a quarter of the exports 

 of the previous year for the same month. 



On page 76 of this Report we mention some Spanish orange peel oils which 

 D. B. Dorronsoro had investigated and described. Since we have ourselves in the last 

 years repeatedly examined Spanish sweet orange oils, we may reproduce our own 

 observations in connection with these researches of Dorronsoro. The oils were 

 distinguished by a strong orange odour and a deep red-brown colour; often oils only 

 one had a lighter colour. The constants varied between the following limits: — di 5 o 0.851 1 

 to 0.8565; « D20O +90° to +96° 44'; the « D of the first 10 per cent, of the distillate in 

 all samples higher (by 9° maximum) than the « D of the original oils; n D20 o 1.47348 to 

 1.47466; evaporation residue 3.4 to 11 per cent; aldehyde (decylaldehyde) 2 ) contents 

 1.2 to 2.7 per cent, (by phenylhydrazine method). The sap. v. found with one evaporation 

 residue was 157.0. 



These values agree on the whole with those of Dorronsoro. From the oils obtained 

 in Italy the Spanish oils differ, apart from odour and especially from colour, partly 



*) Cf. Gildemeister and Hoffmann, The Volatile Oils, 2 nd ed., vol. I, p. 410. — 2 ) According to 

 K. Stephan {Report October 1900, 29) sweet orange-peel oil contains only decyl aldehyde. Dorronsoro (Joe. cit.) 

 speaks erroneously of citral. 



