236 COMPOSITION AND PRODUCTS OF 



bility in this menstruum. When heated to a high degree it 

 volatilizes without leaving a residue. The alcoholic solution 

 reddens litmus. 



The physical properties of this acid will be seen to differ 

 from those of margaric acid, which it has been supposed to be ; 

 but there is no striking difference between these two bodies 

 in composition, as will be seen in the results afforded by the 

 analysis of this body. 



Exp. 1. — 0.2815 gramme of the acid burnt with the bioxide 

 of copper gave* 0.7725 gramme carbonic acid and 0.320 gramme 

 water. 



Exp. 2. — 0.2325 gramme of the acid burnt with the bioxide 

 of copper gave 0.637 gramme carbonic acid and 0.261 gramme 

 water. 



Exp. 3. — 0.328 gramme of the acid burnt with the chromate 

 of lead gave 0.890 gramme carbonic acid and 0.3685 gramme 

 water. 



These three analyses furnish the following proportions of 

 carbon, hydrogen, and oxygen in 100 parts of the acid: 



Carbon 75.44 75.31 74.64 75.13 1 



Hydrogen 12.60 12.47 12.46 12.51 



Oxygen 12.96 12.22 12.90 12.36 



100.00 100.00 100.00 100.00 



Having thus found the relative proportions of the elements 

 contained in this acid, it was necessary to examine one of its 

 salts to ascertain its atomic composition, and for this purpose, 

 as in most cases, its combination with the oxide of silver was 

 chosen ; but to form this salt it was necessary first to form its 

 soda-salt. 



Soda-salt. — A portion of the acid was digested with a solution 

 of carbonate of soda until a complete combination had taken 

 place, which is easily known by the acid no longer floating on 

 its surface, it having all united with the soda, forming a salt 

 soluble in water. The solution of this salt, which contained 



* All my calculations are made with the atomic weight of carbon given 

 by Liebig and Redenbacker (75.85 oxygen being considered 100, or 6.068 

 hydrogen being taken as unity). 



t Composition of margaric acid after the analysis of Varrentrapp : Carbon, 

 75.35; Hydrogen, 12.33; Oxygen, 12.32. 



