106 Dr. L. Playfair on a new Fat Acid 



the acid had been combined, together with acetic and hydro- 

 sulphuric acids. During the evaporation of the liquid, the 

 two latter were expelled, and a thick straw-coloured liquor of 

 a syrupy consistence and sweet taste remained, which pos- 

 sessed all the common characters of the oxide of glyceril. 

 The following are the results of the analyses of sericine. 



I. 0*3045 gramme of substance yielded 0*34'4 gramme of 

 water, and 0-y32 gramme carbonic acid. 



II. 0-406 gramme of substance yielded 0*452 gramme of 

 water, and 1*104 gramme of carbonic acid. 



III. 0*310 gramme of substance yielded 0*341 gramme of 

 water, and 0*847 gramme of carbonic acid. 



I. II. III. 



Carbon 75*55 75*19 75*55 



Hydrogen ... 12*18 12*30 12*22 



Oxygen 12*27 12*45 12*23 



100-00 100*00 100*00 



Lecanu has endeavoured to show that stearin (the stear- 

 ate of the oxide of glyceril) is composed of two atoms of 

 stearic acid, and one atom of a peculiar oxide of glyceril repre- 

 sented by the formula Cg H(j O4. But Pelouze has proved that 

 the common oxide of glyceril should be represented by the 

 formula C,,- H- O5. Meyer, in his researches upon elaidic 

 acid, has also shown that Lecanu's formula for glyceril is cor- 

 rect in some combinations of the fat acids ; although it may 

 reasonably be questioned whether it possesses this composi- 

 tion in stearin ; for Liebig has shown it to possess the formula 

 2 St + Gy + 2 HO. Liebig does not deny that other 

 oxides of glyceril may exist besides that expressed by the 

 formula Cg H7 O5 ; on the contrary, he suggests that there 

 may be several, which may unite with one, two, or three atoms 

 of anhydrous acid, just as there are acids which unite with 

 one, two, or three atoms of a base. But very little is known 

 regarding the nature of glyceril. 



Sericine may be an example of such a combination, con- 

 taining an oxide of glyceril, C^ H5 O3, capable of uniting with 

 four atoms of an anhydrous fat acid. These different gly- 

 cerins would be formed by the removal of one or two atoms 

 of water from the common oxide of glyceril. The hydrogen 

 shown by the analysis is a little too high to countenance this 

 idea; but this may be partly accounted for by the aether with 

 which it is prepared, and which adheres to it with much obs- 

 tinacy. The formula would be 4 (Cgg H27 O3) + (Q H^ Og). 



