/ 



/ 



/ 



1894] certain Indian. Food t:3tujfii. 75 



On thk loss of Glycerin by Volatilisation. 



2165 gm. glycerin were diluted with water to 250c. c. ; 50c. c. were 

 each time mixed with 25 c. c. pure alcohol, the latter evaporated oi? on 

 a water-bath in — 



(1) A platinum basin of 3 iu. diameter. 



(2) A porcelain basin of 5 in. diameter. 



(3) Do. do. of about 3 in. diameter. 



In (1) and (2) the percentage of glycerin was found to be 74'0; 

 in (3) the percentage was 77'8. The percentage as found before (see 

 p. 69) should have been 80. 



It is thus evident that during the evaporation of alcohol consider- 

 able quantities of glycerin are carried off. 



IODINE ABSORPTION FOR FATS AND OILS.t 



CocoANUT Oil. 



The sample was the same as used for the determination of the 

 saponification equivalent. 



1. 1*3585 gm. oil were digested for 24 hours with 10 c. c. chloro- 

 form and 20c. c. iodine solution. In this as well as in the subsequent 

 analyses a blank experiment was each time made side by side, and 

 under exactly similar conditions, to determine the strength of the iodine 

 solution. The time allowed for digestion was from 18 to 24 houi-s. 



20c. c. iod. sol. -f 10c. c. CHCl3 = 35-0c. c. NagSgOg (Blank exp.) 

 Excess of iodine =27-5 „ ,, 



Diff. = 7-5 „ 

 7*5 c. c NagSgOg represent the amount of iodine absoi'bed by the oil. 

 But Ic. c. Na2S203 = 0-01265 gm. iodine. 



Hence amount of iodine consumed by 100 gm. oil, " iodine degree," 

 0-01265 X 7-5x100 ^ ^^ 



= r3585 =^'^^- 



But the actual strength of the thiosulphate solution, as checked 

 by titration against pure iodine, was found to be equal to 0'0I265 

 (1 — 0'03) gm. per Ic. c. 



Corrected iodine number =6-99 (1-0-03) = 6-78. 



2. 1*459 gm. oil were digested as before. 



26*5 cc NagSgOg sol. were taken up by the excess of iodine, and 



20 c. c. iod. sol. =35*0c. c. NagSgOg. 



, ,. , 0-01265x8*5x100 „ ^^ 

 lodme degree = 5=7*3/ 



Corrected number =7-37 (1-0*03) = 7*15 



t For details of Hubr.s method, see Journ. See, Chem. Ind. iii, 642 aleo 

 Allen's Org. Analysis, 



