Mr. De la Rue on Cochineal, 



491 



These numbers correspond with the following per-centage 

 quantities : — 



I. II. 



Carbon . » 29-05 



Hydrogen 3*97 



Oxide of ammonium . . 15"91 



agreeing closely with the following formula, 

 C,6H3N3 0,6,2NH4 + HO, 



as may be seen by a comparison of the theoretical and expe- 

 rimental numbers. 



Theory. 



Carbon . 16 

 Hydrogen 12 

 Nitrogen . 5 

 Oxygen . 19 



96 

 12 



70 

 152 



330 



29-09 



3-64 



21-21 



46'06 



100-00 



Experiment. 



29-05 



' 3-97 



Or 



Nitrococcusate of Baryta was prepared by adding an excess 

 of a solution of baryta to an aqueous solution of nitrococcusic 

 acid, a stream of carbonic acid gas being passed through the 

 solution to separate the excess of baryta. The solution was 

 warmed, filtered and evaporated in a water-bath, and again 

 filtered from a small quantity of carbonate of baryta. The 

 evaporation being continued until a pellicle formed on the 

 surface, the solution on cooling deposited this salt in minute 

 yellow crystals. It is insoluble in alcohol, which precipitates 

 it in the form of a jelly from the aqueous solution. 



I. -6750 grm. of substance dried at 100° C. and decom- 

 posed by sulphuric acid, gave '3602 grm. of sulphate of 

 baryta. 



II. -6439 grm. of nitrococcusate of baryta dried at 100° 

 C. and burnt with chromate of lead, gave -5185 grm. of car- 

 bonic acid and -0800 grm. of water. 



These numbers correspond to the following per-centage 

 quantities: — 



I. II. 



Carbon 21'96 



Hydrogen 1*38 



Baryta 35-06 



