— 47 - 



According to our observations the characteristics of mandarin oil 

 pressed from the ripe fruit are as follows: d 15Q 0,854 to 0,859, « D + 65 

 to 75°, « D of the initial 10% of the distillate a little lower, or up to 

 about 2° higher, than « D of the original sample; n D20 o 1,475 to 1,478, acid v. 

 up to 1,7, ester v. 5 to 10, evaporation-residue 2,4 to 3,5%. 



Orange Oil, Sweet. In an article entitled "le droit de conclure", 

 G. Courtz 1 ) attacks the judgment given by a German laboratory on a sample 

 of sweet orange oil. The sample in question was found to be abnormal 

 in a peculiar manner so far as its more than usually dark colour and its 

 high evaporation-residue were concerned, but it was held that deliberate 

 adulteration could only be surmised when such adulteration could yield a 

 pecuniary advantage and that this was not the case with the sample 

 under investigation, first of all because it came from a different district 

 than the ordinary oil of commerce, and secondly because the addition of 

 only about 3°/o of foreign matter could not be held to be due to financial 

 considerations. 



The German Laboratory referred to by Courtz being our own, we 

 will briefly explain matters here. One of our clients submitted to us for 

 our opinion a sample of sweet orange oil weighing only a few grams. Our 

 analysis showed the following characteristics: d i5 o 0,8535, « D + 91°38', 

 « D of the initial 10°/o +93°0', evaporation-residue 8,8°/o. We therefore 

 gave it as our opinion that the specific gravity and the optical behaviour 

 of the oil agreed with those of bitter orange oil, and that, moreover, the 

 abnormally high evaporation residue and the characteristics of that residue 

 made it probable that the oil had been adulterated with a fatty oil. The 

 firm which had supplied the oil protested against this finding, and as a 

 result we asked for, and received, a larger parcel of the oil in order that 

 we might make a more thoroughgoing investigation. The oil now gave 

 the following constants: d 15 o 0,8555, « D20 o + 92° 24', « D of the initial 10°/o 

 -r98°4', evaporation-residue 9,5%. 



The difference in the constants of the two samples was to be ex- 

 plained by the fact that when the bottle containing the first sample was 

 rinsed out with spirit, a little alcohol had got into the oil, but could no 

 longer be detected. As regards the constants of the second sample, 

 only the rotation of the initial 10% corresponded to that of the values 

 which had been found by us for pure sweet orange oils 2 ), while the other 

 constants were incompatible with purity. Subsequent exhaustive exami- 

 nation of the evaporation-residue showed without a doubt the presence 

 of a fatty substance. 



In contradistinction to the evaporation-residue of pure oils of orange, 

 the residue of the sample under examination made a clear solution with 



'-) Parfum. moderne 4 (1911), 68. 

 2 ) Report April 1911, 72. 



