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*) This applies particularly to American peppermint oil; English oil generally gives 

 solutions which remain clear even when diluted. 



2 ) The separation of menthol must, if necessary, be induced by inoculation with a 

 menthol crystal. 



Pine-needle Oil. (Oleum Pini foliorum; Oleum Pini silvestris) 1 ). 

 Colourless or bright yellow; di 5 o 0,870 to 0,890; soluble in 7 parts 95°/ 

 alcohol, less readily in 70% alcohol. 



x ) As the oil distilled from the needles of the common pine, Pinus silvestris, L. has a 

 somewhat unpleasant odour, and is difficult to procure in commerce, and as, moreover, the 

 term Oleum Pini silvestris is an old and incorrect denomination for oil from the cones of 

 Abies alba ("TemplindV), it would be more correct to prescribe Oleum templini, of which the 

 sp. gr. ranges from 0,851 to 0,870. Comp. Report April 1909,79. 



Rose Oil (Oleum Rosce). Colourless 1 ) or slightly yellowish; d i5 o 0,87 to 

 0,89 2 ); readily soluble in ether and chloroform, less readily in 90% alcohol; 

 at -f- 18° to +21° needle-shaped crystals are separated out, at +5° the 

 oil congeals into a crystalline mass 3 ); when 1 part of oil is dissolved in 

 5 parts of chloroform, and 20 parts of 90% alcohol added, lustrous crystals 

 begin to separate out after a time; the liquid, when separated from the 

 crystals, must give no colour-reaction with ferric chloride solution. 



*) Rose oil is never colourless, but always yellowish. 



2 ) Seeing that owing to the separation of paraffin the oil is usually in a solid 

 condition at -j- 15° it is advisable to determine the sp. gr. at a higher temperature •* 

 d~ 0,849 to 0,863. 



3 ) Rose oil solidifies at a higher temperature. 



Rosemary Oil (Oleum Rosmarini). Colourless or yellowish; di 5 o0,90 to 

 0,92; « D to the left 1 ); soluble in any proportion of 90% alcohol 2 ). 



x ) Dextrorotation is, on the contrary, a special characteristic of rosemary oil; pure oils 

 which are laevorotatory are only rarely met with ; in the great majority of instances, laevorotation 

 is caused by adulteration with French turpentine oil. 



2 ) Initial turbidity is to be attributed to the fact that the oil always contains water. 



Sandalwood Oil (Oleum santali). Faintly yellowish; d 15 o 0,970 to 0,980^; 

 passes over almost entirely below 300°; soluble in 5 parts of 70% alcohol. 



x ) The sp. gr. ranges from 0,975 to 0,985 (15°). On the behaviour of sandalwood oil 

 in boiling comp. Gildemeister and Hoffmann "The Volatile Oils", p. 340. 



Spearmint Oil (Oleum Mentlwe crispce). Colourless or yellowish, turns 

 more viscous and darker in the air; di 5 o 0,900 to 0,940; readily soluble in 

 90% alcohol 1 ). 



1 ) The dilute solution has an opalescent turbidity. 



Thyme Oil (Oleum Thymi). Colourless or yellowish 1 ); di 5 o 0,90 to 

 0,91 2 ); soluble in any proportion in 90% alcohol; phenol-content not 

 less than 20%. 



x ) Rectified thyme oils also gradually revert to the red-brown colour of the crude oil. 



2 ) As thyme oil occasionally has a sp. gr. above 0,91, it would be more correct to require 

 only that the sp. gr. must not be below 0,90. 



Thymol (Thymolum). Colourless, transparent crystals; m. p. 50 to 51°; 

 b. p. 228 to 230° *); readily soluble in alcohol, ether, chloroform, benzene, 



