RAPE-SEED <HI, 



valuo of this oil \\ould make >mall addit ions of it dillicult of detec- 

 tion. it i> not so well adapted as a substitute for olive oil as the 

 products previously mentioned under thi> class, owing to the acrid 

 ta-te of even the well-refined oil. Analyses of rape and col/a oils are 

 given in Table XXVIII. 



T.Mtl.K \ N \'I 1 I. - 



/ Uii'l rnljl nils. 



"7 samples. Jour. Soc. Chem. Ind., 1898, 17: 989. 



'1 samples. 



J samples. Bulletin du Ministrn- de I'Atq-ieulture, 1895, p. 139. 



-'1 1 samples. Annali del Laboratorio chimico centrale delle Gabelle, vol. 2, (ili olii, pt. 'J, p. Jti. 



e Annali del Laboratorio chimico centrale delle Gabelle, vol. 2, Gli olii, pt. 2, p. 21;. 



The specific gravities of these oils are practically identical with that of 

 the olive; the index of refraction, iodin number, and rise of tempera- 

 ture with sulphuric acid are considerably higher. The saponih'cation 

 number is much lower than for olive oil or for any of the oils used to 

 adulterate it, with the exception of the other members of the rape-oil 

 group. The average saponification value given for rape oil is about 

 173, while the average value for olive oil is about liW. and an olive oil 

 having a saponification value much below 190 should be looked upon 

 with suspicion. An addition of less than 20 per cent of rape oil would 

 probably be difficult to detect, but this amount should be sufficient to 

 mate rial 1\ T affect the values of a normal olive oil. Low specific gra\ it v 

 accompanied by a high index of refraction is one of the marked char- 

 acteristics of rape oil,, wherein it differs from most oils which with a 

 low specific gravity have a low refractive index. 



Valenta rt has suggested the differentiation of oils by their solubility 

 in glacial acetic acid of 1.0562 specific gravity, and states that rape and 

 mustard oils are the only common oils not completely soluble in this 



"Dingier, 18S4. 2.V2: l^fi: Jour. ('hem. So<-., 1SS4, 4(5: H)7s. 



