Commercial and scientific notes on essential oils. 39 



Blandini's assertion 1 ) that the floivers produce a larger quantity of oil of excellent 

 quality is in Knuth's opinion certainly not in accordance with the facts. 



As to the geographical distribution of the plant, the author gives the following 

 summary, many facts of which will be known already from our previous Reports. In 

 France the plant was first cultivated near Grasse and at the foot of the Maritime Alps, 

 near Cannes. Though it was known there as early as 1819, it seems to have been 

 grown only to a limited extent up to 1847. Shortly after that time, emigrants trans- 

 mitted the cultivation to Algeria, where the plant was first grown in the district of 

 Sahel, Western Algeria, between Oran and Mostaganem, afterwards in the plain of 

 Metidja, near Algiers, and in the littoral of the province of Constantine, near Philippeville 

 and Bougie. The cultivation did not spread to Reunion before 1880. It was favoured 

 there by the sugar crisis of 1904—1906. — In the Spanish province of Granada, experiments 

 regarding the cultivation of the plant were made about 1890. Although the quality of 

 the oil was excellent, the area of cultivation, producing from 600 to 1000 kilos annually, 

 was not increased. — In the Jewish colonies of Asia Minor, Rischon-le-Zion and Petach- 

 Tikway, there are plantations which were founded by Baron Rothschild. — The trial 

 plantations of Pelargonium radula in Limaru, British East Africa, have not been 

 continued. — The author states that he has not been able to obtain information con- 

 cerning the cultivation of the plant in Corsica. We would mention that it was introduced 

 there from the Provence, about 1860, and quickly spread in the districts of Erbalunga, 

 Sisco and Brando. 



We have reported repeatedly on adulterations of geranium oil with citronella oil 

 or fractions thereof 2 ). It is often difficult to recognize such admixtures, as the constants 

 are not always influenced sufficiently to become abnormal. Under these circumstances, 

 a careful examination of the smell will rouse suspicion, but only an exact chemical 

 analysis can give absolute certainly. 



We had to deal with such a case quite recently, when a geranium oil was sent us 

 for inspection from Spain. It behaved as follows: — d t5 o 0.9002, « D — 6°38', n D20 o 1.47171, 

 acid v. 5.2, ester v. 50.8 = 21.4 per cent, ester, calculated as geranyl tiglinate, ester v. 

 after acetylation 213.7 = 70 per cent, total geraniol, soluble in 2.3 vols, and more of 

 70 per cent, alcohol, dilute solution slightly turbid. As the product was supposed to 

 be a Bourbon oil, it struck us that the constants were abnormal in part, the specific 

 gravity and the index of refraction being too high, the optical rotation too low. The 

 sample therefore resembled rather an African distillate, but was suspicious in any case 

 on account of its odour and defective solubility. It was proved through investigation 

 that the oil contained an appreciable quantity of citronellal, a substance which is not 

 a component of geranium oil. With the aid of bisulphite, several grams of citronellal 

 were isolated out of 125 grams of the oil under examination and identified by means 

 of the semicarbazone, melting between 82 and 83°. A mixture with a semicarbazone 

 prepared for the sake of comparison showed the same melting point, so that the identity 

 of the two compounds is certain. 



In order to make quite sure, we treated 125 grams each of genuine pure Bourbon 

 and African geranium oils in the same way with sodium bisulphite, when the quantities 

 of aldehydic components obtained were so small that a chemical identification resulted 

 impossible, whereas the smell seemed to indicate citral or a fatty aldehyde rather 

 than citronellal. 



x ) Bull, fla VOff. du Gouv. de VAlgerie 12 (1906), 277. Comp. Gildemeister and Hoffmann, The Volatile Oils, 

 2"i edition, vol. II, p. 614, foot-note 5. — 2 ) Comp. Report 1917, 19 and Bericht (German) 1920, 36. 



