18^4.] certain Indian Food Stuffs. 69 



A c. c. il KMn 0^=0-0028 gm. CaO V The two results were found to 



be thoroughly concordant. 



(6) Oxidation of glycerin to oxalic acid ; — 



1. 5*62 gm. of glycerin were weighed into a flask and diluted to 



600 c. c. with water. 25 c. c. of the solution were oxidised to oxalic acid.* 



5"62 

 25 c. c. sol. = -2Tr gm. glycerin = 0-281 gm. glycerin on the sup- 



position that the sample contained cent, per cent, of glycerin. 



The potassiiim oxalate solution was made up to 500 c. c. of which J 00 

 c. c. gave 0-028 gm. CaO (by ignition) 



or 500 c. c. KO Sol. = 0-028 x 5 gm. CaO = 0-02 x 5 Ca 



But 0-002 gm. Ca= 0-0046 gm. glycerin. 



.'. 0'02 gm. Ca=0-046 gm. glycerin. 



or (0-02x5) gm. Ca= 0-046x5 gm. glycerin = 0-23 gm. glycerin. 



0'23 



The Sample thus contained lOOx ^voot ' °^ ^^'^°lc o^ glycerin. 



2, 5*895 gm. glycerin (the same sample) were dissolved in water 

 and diluted to 500 c. c, of which 25 c. c. were oxidised to oxalic acid. 



25 c. c. sol. = ■ • ' ■ gm. = 0-2947 gm. glycerin. 



The oxalate solution was made up to 500 c. c, of which 100 c. c. 

 yielded 0-0285 gm. CaO = 0-02035 gm. Ca. 



But 1 c. c. ^ KMnO^ =0-002 Ca from CaC204 



=0*0046 gm. glycerin. 

 .'. 0-02035 gm. Ca =0-046805 gm. glyc. 



or 500 c. c. oxalate sol. = (0-046805 x 6) gm. giyc. 



= 234 gm. glyc. 



0-234 

 The sample thus contained 100 x-rpnTn o^ '''^■'^^"/o glycerin. 



The mean of the above two determinations may be taken as 80 "/„ 

 approximately. 



Sapoxification of Mustard Oil. 

 (Estimation of glycerin.) 

 1. 8*65 gm. oil were saponified according to Allen's method.f 

 The soap solution was treated with dilute sulphimc acid, the beaker in 



* Au abstract of Benedikt and Zsigmoudy's method will be found in Jour. Soc. 

 Chem. Ind. IV, 610. 



+ The use of alcoholic potash is highly objectionable; "pure methyl alcohol" is 

 difficult to procure. " Hence," as Allen remarks,, " I have latterly aimed at 



