— 44 — 



as a rule applies, he has observed that there are also good lavender 

 oils which contain only 20 to 3O°/ ester. 1 ) Such oils are found in 

 the Alps near the Franco-Italian frontier, and the annual production 

 (about 5000 kilos) is in Birckenstock' s opinion of sufficient importance 

 to take the particular properties of these oils into account. They have 

 a very fine bouquet, but no "body". The content of linalool amounts 

 to about 5O°/ , and is therefore normal, but, as already mentioned, 

 the ester-content is only 20 to 3O°/ ; they are also characterised by 

 a low specific gravity (0,878 to 0,882), and by a considerable laevo- 

 rotation ( — 8 to — 9 ); they are, moreover, very readily soluble in 

 alcohol (in 10 to 12 vol. 60 per cent, alcohol). 



A further exception to the rule, according to Birckenstock, is 

 made by the varieties standing between lavender and spike. If, namely, 

 lavender comes below 2300 to 2600 feet, it crosses with spike, "elle 

 s'aspique"; the hybrids thus formed are known among distillers by 

 the names of el lavandin" or "spigoure" , and they represent every 

 possible transition between lavender and spike, according to the con- 

 ditions due to altitude and state of the soil. In this connection 

 Birckenstock 's statements on the morphological differences between 

 lavender and spike are also interesting; lavender has a non-ramified 

 stalk, which is rarely longer than 16 inches; the blossoms are blue- 

 violet, and have thin, heart-shaped, pointed sepals which are shorter 

 than the bluish calyx. 



The spike plant is larger than the lavender. The stalks frequently 

 have several ramifications, and grow to a height of up to 32 and 

 36 inches. The sepals are linear and of the same length as the calyx, 

 which in this case is not bluish, but whitish. 



The influence of cross-fertilisation also shows itself in the pro- 

 perties of the essential oils, which behave entirely like mixtures of 

 lavender oil and spike oil. Birckenstock has in the course of his 

 observations examined a whole series of oils, from typical lavender 

 oil to typical spike oil. He then found at the same time that towards 

 lavender oil not only the ester-content and alcohol-content increase, 

 but that also a gradual change takes place in the proportion of borneol 

 to linalool and geraniol; whereas in spike oil borneol predominates, 

 it diminishes towards lavender oil more and more as compared with 

 linalool and geraniol. We give here still the properties of two charac- 

 teristic lavandin oils: 



1. diso 0,9027; «d — o°43 / ; ester-content 6,23 °/ ; alcohol- content 

 (C 10 H 18 O) 34,8 °/ ; soluble in 3 vol. 65 percent, alcohol. 



2. 0450 0,8995; «r> — I °35 / 5 ester-content 9,12 °/ ; alcohol-content 

 36,5%; soluble in 3 vol. 65 per cent, alcohol. 



*) Comp. Report October 1904, 51. 



