1694.] certain Indian Food iStuffs. 71 



oxalate as OaO cannot be dispensed with. These experiences are in con- 

 formity with those of Allen and Belchei\ Two more saponifications 

 carried on as above yielded the percentage of glycerin as 5 '3 aud 6*0 

 respectively. 



An Improved Method of Saponification. 



It is thus evident that the saponification was by no means com- 

 plete, as the percentage of glycerin ranged between 8" 14 and 4!'8. 

 Allen's method had thus to be abandoned. It was, in fact, noticed that 

 the oily layer invariably floated over the solution of caustic potash and 

 that shaking simply brought about a momentary incorporation of the 

 oil and alkali. The two layers separated as soon as the bottle was 

 placed in the boiling water. This difficulty was obviated *by the intro- 

 duction into the bottle of asbestos wool, thoroughly ignited previovisly to 

 get rid of accidental organic impurities. This absorbing medium brought 

 the oil and the alkali into intimate contact with each other and thus 

 complete saponification was ensured. The heating was done just as in 

 the previous cases, i. e., by immersion in boiling water. 



1. 1'573 gm. oil were treated as above, the fatty acids liberated by 

 means of dilute HgSOj, and filtered off. The mass of asbestos, which 

 had become slimy by the absorption of the fatty acids was then thrown 

 on the filter-paper and repeatedly exhausted with hot water. Scarcely 

 a trace of the fatty acids was found to pass through the filter-pajDcr.* 

 The filtration was carried on with the aid of a Bunsen's pump. 



The glycerin solution was made up to 250c. c, of which 100 c.c. were 

 oxidised to oxalic acid. The latter thrown down as CaO. The CaO 

 dissolved in dilute HgSO^ and the solution made up to 250 c. c, of which 



N 

 100 c.c. reqd. 4-7c. c. — KMnO^ 



or 250 ,, „ I1'75 „ ,, ( = 100c.c. glycerin sol.) 



N 

 .-. 2.50 c.c. glycerin solution = 29-37 c. c. — KMnO^ 



and Ic. c. — KMn04 = 0-0046 gm. glyc. 



.•.29-37 „ „ =0-135102 gm. glyc. 



or 1-573 gm. oil yielded 0-135102 gm. glyc. 

 whence glycei'in °/q = 8-6 



2. 2-167 gram, oil were saponified as above. 



The glycerin solution made up to 250 c. c. of which 100 c. c. 



* The filtered solution of glycerin was sometimes perfectly clear, sometimes 

 slightly opalescent. 



