Notes on scientific research. 129 



acetate, eucalyptol, paraffins, aliphatic ketones, and a few aromatic ketones. Borneol 

 and fenchyl alcohol are oxidised into stable ketones. Among the hydrocarbons, cymene 

 is rather refractory, but with the terpenes oxidation takes place very readily; in the 

 case of camphene alone it proceeds somewhat more slowly. Among the oils which 

 were tested the following were completely or almost completely oxidised by the 

 process: oils of lemon, orange, turpentine, Java citronella (1 p. c. residue), lemongrass, 

 linaloe, coriander, petitgrain, caraway, bitter almonds, cassia, wintergreen, bay, pimento, 

 clove, cinnamon leaf and nutmeg. Other oils, according to their constitution, left a 

 more or less considerable residue, for instance: oil of juniper berries left 4 p.c, 

 sassafras 5 p.c. (including camphor), lavender 5 to 10 p.c, cardamom 8 p.c. (chiefly 

 eucalyptol), cumin 20 p.c. (cymene), rosemary 35 p.c. (camphor, bornylacetate), spike 

 41 p.c. (eucalyptol, camphor), Siberian pine needle oil 60 p.c. (chiefly bornyl acetate) 

 and oil of rue 90 p. c. (methylnonyl- and methylheptyl ketone). 



According to Dodge, the potassium permanganate method is useful for detecting 

 the presence of petroleum in turpentine oil and in citronella oil, as well as for the 

 estimation of cineol. 



For 10 cc. turpentine oil (which, as stated above, is completely oxidised), Dodge 

 uses from 800 to 850 cc. potassium permanganate solution. 



In the case of Ceylon citronella oil, it may happen that the non-oxidised portion 

 contains a little camphor, generated from the borneol which is present in the oil, as 

 a result of the permanganate treatment. This camphor can be removed with cold 

 80 p. c. sulphuric acid. Any residual petroleum may be detected by the fact that at 

 0° it does not mix with castor oil. 



Dodge also recommends the method for distinguishing (and possibly for quanti- 

 tatively estimating) bornyl acetate from the isomerous linalyl, geranyl and terpinyl 

 acetates; bornyl acetate alone being stable. By subtraction from the total esters, 

 which are determined by quantitative saponification, that portion of the esters which 

 has been attacked by the potassium permanganate is estimated. By this method, Dodge 

 found a Siberian pine-needle oil with 45,8 p. c. total esters to contain 38,3 p. c. bornyl 

 acetate and 7,5 p.c. oxidisable esters (terpinyl acetate?), while a rosemary oil with 

 5,78 p.c. total esters contained 1,33 p.c. bornyl acetate and 4,45 p.c. of other esters. 



We may here point out that the method of separating sparingly oxidisable bodies 

 from others which are more readily oxidisable, by shaking with potassium permanganate 

 solution, has long been known. We ourselves have frequently used it successfully in 

 our investigations. Compare, for instance, Schimmel's Bericht April 1897, 50; Report 

 April 1902, 24; April 1903, 25, 74; October 1912, 79. 



Physical Notes. 



L. Gurwitsch 1 ) has made comparative experiments in the fractional distillation of 

 oil-mixtures, both with and without steam, and has confirmed the theoretical conclusion 

 that the passing-through of steam favourably affects fractionation. The author took 

 care to work as far as possible under the same conditions and with the same apparatus. 

 In order to obviate any possible dephlegmation he placed the entire still, together 

 with its delivery tubes, in an oil-bath. For each experiment he took 1 litre of liquid- 

 mixture, of which about 100 cc. was driven off. He used carefully purified Russian 

 "Meteor" burning oil in his experiments. In lieu of introducing steam from without 



J ) Zeitac.hr. f. angew. Chem. 26, I. (1913), 102. 



