348 BROOKS. 



The green oranges \yeigh, on an average, about 160 grams, of which 

 about 40 grams are peel. On an average the peel of a green orange 

 yields, on squeezing by hand, about 0.5 gram of oil and 2 cubic centi- 

 meters of an aqueous solution which contains a considerable amount of 

 reducing sugars. No evidence of the presence of a glucoside was found. 

 The freshly pressed oil has the following constants Ester number, 8.0 ; 

 optical rotation, A^, 90.85° ; refractive index, N^^!, 1.4700. 



On standing a few days, the freshly pressed oil deposits about 0.3 per cent 

 of a crystalline, wax-like substance, perhaps identical with the orange-oil stear- 

 eoptene which separates from Italian sweet-orange oil. By squeezing the peels 

 into alcohol and precipitating with water an oil is obtained which does not 

 deposit any sediment on standing. One such sample gave, on spontaneous eva- 

 poration, a residue of 2.25 per cent of the solid. Another specimen of oil, 

 obtained by pressing only, left a residue of 2.4 per cent. After recrystallizing 

 the solid several times from dilute alcohol, it showed the melting point 116° to 

 117°. 



The constants given above agree well with those of the orange-peel oil of 



commerce. Schimmel and Company " assign the following limits to the constants 



90° 

 of oil of sweet-orange peel: di5°=0.843 to 0.853: (D)=^=:95° to 98°. The 



residue on evaporation should be between 2.0 and 4.0 per cent. 



In order further to confirm the character of this oil it was investigated and 

 found to contain about 92 per cent of limonene. Wallach'^ found about 90 per 

 cent of limonene in a European sweet-orange-peel oil. 



As orange-peel oil has been investigated very thorouglily, it was not 

 deemed necessary to repeat previous researches in this instance. The 

 oil in question appears to be identical with the orange-peel oil of com- 

 merce. 



30° 

 One hundred and five grams of oil gave 96 grams of limonene, A ^=— = 93.20° 



and 4.5 grams of oil boiling from 180° to 230°. This fraction was redistilled but 

 the quantities of substances obtained were too small for identification. About 

 0.5 gram of an acid was secured, the odor of which was slightly suggestive of 

 butyric acid, but the odor of the ester closely resembled that of caprylic ester. 

 The acid fraction also contained a trace of a phenolic substance which gave an in- 

 tense, wine-red to violet coloration with ferric chloride. 



The odor of the Philippine oil is Just as fine as the oil produced 

 elsewhere, being decidedly sweeter than several samples of Sicilian oil 

 procured in Manila. However, the latter samples undoubtedly had de- 

 teriorated during storage. 



The oil from the cajel variety of orange is very difficult to press out of the 

 peel, as the oil cells are set very deeply. It does not differ perceptibly in frag- 

 rance from the oil of the naranjita and the yield is so small that no attempt 

 was made to prepare a quantity of it. A small sample showed the refractive 



or\o 



index, 1.4675: the specific gravity £!^, 0.8390: and the saponification numl)er, 8.5. 



30° 



I "Bulletin of Schimmel and Co. (1906), 3, 35. 



'Mwn. d. Chem., (Liebig) (1884), 227, 289. 



