Mr. De la Rue on Cochineal. 495 



phuric acid, they all gave the following results : on acquiring 

 a syrupy consistence, a white chalky-hke matter subsided; 

 this was separated by filtration, and proved to be a new cry- 

 stalline body. The liquor filtered off from this substance 

 deposited a small quantity more on further concentration, and 

 could only be dried to a soft tenacious mass, partly soluble in 

 alcohol, the rest being soluble in water. From three pounds 

 of cochineal five ounces of this soft matter were obtained, 

 showing that the precipitation by a lead salt had effected the 

 separation of carminic acid from a large quantity of foreign 

 matters. This gelatinous matter appears to be of a complex 

 character, but I have not yet examined it fully. 



To purify the chalky-like matter, it was well-washed with 

 cold water and crystallized twice by solution in boiling water 

 and evaporation ; it w as then dissolved by boiling it in a just 

 sufficient quantity of water ; animal charcoal was now added, 

 and the ebullition continued for a few minutes ; the solution 

 filtered whilst hot deposited on cooling a mass of silky cry- 

 stalUne tufts, completely filUng the liquid, and when collected 

 and dried they aggregated into paper- like masses of a silky 

 aspect. I obtained in three experiments 4 parts of the new 

 body from 1000 of cochineal. 



I. '4918 grm. of substance, preparation {a), dried in vacuo 

 and burnt with oxide of copper, gave 1*0705 grm. carbonic 

 acid and 0*2838 grm. water. 



II. '5680 grm. of substance {b) gave 1*2416 grm. carbonic 

 acid and *3160 grm. water. 



III. '4700 grm. of substance {b) gave 1*0210 grm. car- 

 bonic acid and *2660 grm. water. 



For the latter analysis I am indebted to the kindness of 

 Mr. Nicholson. 



A qualitative examination having pointed out the presence 

 of nitrogen, it Mas determined by Varrentrapp and Will's 

 method. 



IV. '5046 grm. of substance (a) dried in vacuo and burnt 

 with soda-lime, gave *6131 grm. ammonio-chloride of pla- 

 tinum. 



V. '5076 grm. of substance [b) gave '6239 grm. ammonio- 

 chloride of platinum. 



From these numbers the following per-centages are calcu- 

 lated : — 



I. II. III. IV. V. 



Carbon . 59*36 59*62 59*25 

 Hydrogen 6*41 6*18 6*29 



Nitrogen . ... ... ... 7*62 7'7l 



