64 



The object of our work is above all to make known in a larger 

 circle our observations and experience gained up to the present in 

 the lavender oil distillation, and in this manner lead to the adoption 

 of a more suitable method of producing the oil. 



With regard to the occurrence of lavender, the botanical features, 

 and the differences and transition-forms existing between lavender and 

 spike we would call special attention to Bircken stock's work, 

 which we discussed already in our last Report 1 ). 



The distillation takes place during the time when lavender is in 

 full bloom, i. e. from the beginning of July to the beginning of 

 September. It is on the whole inadvisable to continue the distillation 

 beyond that time, as the inflorescences become poorer in blossoms; 

 along with this a decrease in the yield of oil takes place. 



Not only the blossoms alone are used, but the whole inflorescence, 

 including the upper green parts of the plant. Strictly speaking, the 

 latter ought not to be cut off along with the rest, but it is usually 

 done. The woody parts of the plant, on the other hand, are not 

 employed. 



The great influence of the manner of distillation on the preserv- 

 ation of the esters was proved in a direct way by experiments. 

 There was an enormous difference in the ester-content of the oils, 

 if the same material was distilled on the one hand with steam, on 

 the other hand by the water distillation method usual in the South 

 of France. In the latter case one of the apparatus commonly employed 

 there was used, and the distillation carried out in the usual manner: 

 50 to 60 kilos blossoms were immersed in an equal quantity of water 

 (for dry blossoms a somewhat larger proportion of water is taken), 

 then distilled, and 16 litres distillate collected. The results thus ob- 

 tained were as follows: — 





Oil yield 

 % 



d 15° 



«D 



% 



ester 



Solubility in 70 per cent, alcohol 



I. 



[ Steam distillation 



0,8l 



0,8894 



-8° 4 



50.9 



Soluble in 6 to 7 or more vol. 

 with faint opalescence 





I Water distillation 



OJI 



0,8871 



-6° 4 7' 



44,0 



Soluble in 3 and more vol. 



2. 



( Steam distillation 



0,82 



0,8905 



-8° 



53,7 



Soluble in about 7 vol. and 

 more with faint opalescence 





l Water distillation 



o,75 



0,8880 



-6°2l' 



43>6 



Soluble in 3,3 and more vol. 



This shows that the loss of ester in the old distillation process, 

 as compared with the steam distillation, is very considerable, and 

 amounts in the one case to 7, in the other even to io°/oJ further, 

 in the steam distillation the oil yield is of course also somewhat greater. 



x ) Report October 1906, 42. 



