— i9 — 



The examination of the dark orange-coloured oil gave the follow- 

 ing results: di 5 , 5 o 0,884, « D — 3,3°, citronellal 36 %> geranioi 4 l0 /o; 

 Schimmers test: the oil gives with 80 per cent, alcohol only a 

 cloudy solution. This inferior solubility of a guaranteed pure oil, in- 

 duces Sage to attack Schimmers test which, as is well known, 

 consists of this, that citronella oil must form a clear solution with 

 1 to 2 vol. 80 per cent, alcohol at -(- 20 , remaining clear or showing 

 at most feeble opalescence when up to 10 vol. solvent are added, from 

 which even on prolonged standing no drops of oil must separate off. 

 Sage designates this test an arbitrary determination, which no doubt 

 may be useful in some cases, but which cannot give information on 

 the quality of the oil; for the latter, only the content of geranioi and 

 citronellal are decisive. For this reason it does not appear desirable, 

 according to Sage, to retain Schimmel's test as a criterion for the 

 purity of the oils. 



In reply to this we would point out that we also have always 

 supported and still support the view that for the quality of citronella 

 oil the content of total geranioi (geranioi -J- citronellal) is above all 

 decisive. But such determinations frequently take up too much time 

 for commercial practice, and for this reason an easy and quickly 

 completed method of testing was desirable, which should at least give 

 general data as to the quality of the oils. Such a method Schimmel's 

 test has proved to be; experience has shown that oils can be tested 

 by it with good results, and it has been thoroughly acknowledged 

 and recommended by leading experts. Mr. Sage's protest will affect 

 it all the less, as the oil examined by him also differs so widely in 

 its specific gravity and content of geranioi -|- citronellal from commercial 

 Ceylon citronella oil 1 ), that a comparison with the latter appears out 

 of place. To what cause these differences must be attributed is a 

 matter which cannot be settled without further inquiry. What calls 

 for particular attention is the fact that in spite of its high content of 

 geranioi -[-citronellal (7 7 °/ ) the oil dissolves so badly. In the numerous 

 commercial oils examined by us, we have always observed that the 

 solubility of citronella oils increases with the content of total geranioi, 

 and that consequently the solubility is most intimately related to the 

 quality of the commercial oils. This fact has even induced us to 

 introduce a "raised Schimmel's test", according to wich citronella 

 oil mixed with 5°/ Russian petroleum must show approximately the 

 same solubility in 80 per cent alcohol as the original oil 2 ). We have 

 in no single instance observed that oils of superior quality have 



*) Common commercial citronella oil Las a specific gravity between 0,900 and 

 0,920 (15 ) and a content of total geranioi (geranioi -J- citronellal) about 6o°/ ; in 

 very few cases up to 7o°/ has been observed. 



2 ) Comp. Reports April 1904, 32; October 1904, 20. 



