Commercial notes and scientific information. 89 



active fraction of the suspect oil (b. p. 255 to 262°) with potassium permanganate in 

 acetone solution and treating the oxidation-product with semicarbazide. The result 

 was a semicarbazone, m. p. 234°, which was completely identical with that obtained 

 from gurjun balsam oil by a similar method. 



As this semicarbazone, as shown by Deussen and Philipp 1 ), is characteristic of 

 gurjun balsam oil, the occurrence of the last-named substance in the rose oil under 

 examination had been proved by us beyond the possibility of doubt. Umney, however, 

 still appears to question this, unless he has misunderstood what we stated on the 

 subject at the time, for in the article quoted above he declares, referring to the rose 

 oil examined by us, that we had found it to contain a strongly lasvorotatory oil, "which 

 in our opinion was possibly the oil of gurjun balsam." We feel bound to enter an 

 energetic protest against such a distortion of the facts. Our chemical examination 

 left no doubt whatever of the nature of the adulteration, and this we expressed in our 

 Report without any ambiguity, as any unbiassed reader of our article will readily admit. 



In our examination we deliberately refrained from colour-tests, because what we 

 were concerned with was the actual detection of gurjun oil, and because a colour- 

 test is always a last resource, with which the investigator willingly dispenses when 

 he has better methods at command. In applying the test recommended by Umney we 

 were unable to detect an addition to rose oil of even 5 p. c. of gurjun balsam oil, 

 hence, for the purpose under discussion, this test is worthless, in spite of which 

 Umney proudly calls it "a positive clue"! 



P. Siedler 2 ), in a lecture, has given an account of the growing of roses and 

 the manufacture of rose oil in Bulgaria, which is of additional interest because the 

 lecturer himself has thoroughly studied the gathering of the flowers and the distillation 

 of the oil on the spot 3 ) in the months of May and June 1912, and because expert reports 

 on this subject are rarely obtainable from this somewhat inaccessible district. 



Kazanlik, which is generally considered to be the centre of the rose-cultivation, 

 is no longer the principal distilling-point, although it may be described as the chief 

 seat of the trade in rose oil. The harvest begins a little later in Kazanlik than in the 

 Gropsu Valley (Gjobsu) which is situated a little further West, and in the first-named 

 place it had not yet begun at the commencement of June. The copper stills which 

 are used throughout the region by those peasants who do not simply content them- 

 selves with rose-growing, were at that time being made and mended in the streets 

 of Kazanlik. 



In Karlovo, on the other hand, the distilling was already in full swing. Here the 

 rose oil is prepared in small distilling sheds by the old method 4 ), which remains in 

 general use to this day. Many people work in outhouses close to their dwellings. 

 These outhouses are built for the purpose and are kept closed; a few large firms however 

 possess works which are equipped on modern lines. 



Broadly speaking, about 3000 kilos of roses are required to yield 1 kilo of oil; 

 the average weight of the flowers is 400 to the kilo; about 30 roses are needed to 

 produce one drop of oil. Apart from the conditions of labour, the oil-yield depends 

 in the first place upon the weather, more oil being produced when the weather is 

 cool and the sky covered than in good weather, because the hot Bulgarian summer- 



!) Liebigs Annalen 369 (1909), 56; 374 (1910), 105. — 2 ) Berichte d. deutsch. pharm. Ges. 22 (1912), 476. — 

 3 ) A map of the rose oil producing district was published in our Report of April 1909, interleaved between 

 pp. 80 and 81. — *) Comp. Gildemeister and Hoffmann, The Volatile Oils, 1 st ed. p. 428. 



