112 MR. EDWARD SCHUNCK ON SOME 



sure to light or on heating the liquid. The alcoliolic solu- 

 tion of the acid gives with acetate of baryta a white gra- 

 nular precipitate, which is soluble, though with difficulty, 

 in boiling alcohol. With acetate of magnesia it gives at 

 first no precipitate ; but after some time a white crystalline 

 deposit is formed, consisting of the magnesia-compound. 

 These reactions belong to the group of fatty acids of which 

 stearic and palmitic acids are members. In order to ascer- 

 tain the exact place in the series occupied by the acid from 

 cotton, it was submitted to analysis, the following being 

 the results obtained. 



I. 0*2895 grm. from East-Indian cotton, after being 

 kept in a state of fusion for several hours in the water- 

 bath, gave 07990 grm. carbonic acid and 0*3365 grm. 

 water. 



II. 0*2270 grm. from American cotton gave 0*6280 grm. 

 carbonic acid and 0*2700 grm. water. 



These numbers lead to the following composition : — 



Calculation. I. II. 



C34 204 75*55 75-27 75-45 



H34 34 12*59 12-91 13-21 



O4 32 11*86 ii'82 11*34 



270 loo'oo 100-00 lOO'OO 



The formula C^^. H34 O^ belongs to margaric acid, one 

 of the products derived from ordinary fats. Modern re- 

 searches have rendered it almost certain that what was 

 formerly called margaric acid is in fact a mixture of ste- 

 aric and palmitic acids. In consequence, however, of the 

 minute quantity of the substance obtained from cotton, 1 

 was unable to undertake any experiments for the purpose 

 of separating its constituents from one another, but was 

 obliged to content myself with proving the presence of one 

 of the ordinary products of the saponification of fats and 

 oils among the bodies extracted from cotton by alkalies. 

 The quantity procured from American cotton was, indeed. 



