211 



on mixing the crude oil with phosphoric acid, and this pasty 

 nature of the phosphate compound could not be overcome even 

 by the addition of an equal volume of pure cineol to the crude 

 oil. When, however, the crude oil was refined by steam distilla- 

 tion by removing from 5 to 10 per cent, of the higher boiling 

 fractions, the cineol content estimated by this method, and 

 calculated for the crude oil, was equal to from 60 to 63 per 

 cent, cineol. 



Even these results are certainly somewhat low, as the 

 addition compound with phosphoric acid was still slightly 

 pasty. From other estimations and comparisons made at the 

 time, it was concluded that a more correct figure was 

 from 65 to 68 per cent, cineol. 



Arsenic Acid Method. — The arsenic acid method, as pro- 

 posed by Turner and Holmes in America in 1914, was also 

 tried with the same control samples as were used above, and 

 although in some cases good results were obtained, it does 

 not generally appear more accurate' than the phosphoric acid 

 method, when working on this oil. It furthermore has the 

 drawback that a powdery addition compound is not obtained, 

 and thus no indication is given as to the probable accuracy 

 of a particular estimation. 



C. The Separation of Terpenes and other Hydrocarbons 



UNABSORBED BY ReSORCINOL SOLUTION. 



The formation of a water soluble compound of cineol and 

 resorcinol formed a ready and convenient method for separ- 

 ating cineol from the hydrocarbons in the oil. The large 

 middle fractions of the steam distillations, consisting almost 

 entirely of cineol and hydrocarbon bodies, were severally used 

 for this separation. They were shaken repeatedly with a 

 50 per cent, resorcinol (aqueous) solution to remove the cineol. 

 Other oxygenated bodies, such as aldehydes, etc., were also 

 largely removed by this treatment. The oil which was not 

 absorbed by the resorcinol solution was steam distilled, and 

 from several estimations was found to constitute about 20 per 

 cent, of the crude oil. 



Fifteen ccs. of one of these fractions, which was not 

 absorbed by resorcinol and which had a rotation of — 13'5°, 

 were distilled and the distillate collected in the following 

 fractions : — ■ ' 



Temperature. Amount. Rotation. 



(a) 175° 0.-176° C. 6iccs. -12-48° 



(b) 176° 0.-177° C. 4 ccs. -12-98° 



(c) 177° 0.-195° 0. ' 3Accs. -12-98° 



The greater part of the last fraction had distilled at 

 180° C. 



