118 PROCEEDINGS OF THE AMERICAN ACADEMY 



The salt consists when first formed of flame-colored needles in 

 globular radiating groups, but becomes deep claret on drying. It is 

 freely soluble in water, not quite so soluble in alcohol, and essentially 

 insoluble in ether ; the alcoholic solution takes on a magenta color 

 when exposed to the air, and the salt seems to absorb carbonic diox- 

 ide readily, although the change of color was more probably due to 

 oxidation. 



Monopotassic Salt of Curcumin KCj^HjgO^ 



If an excess of potassic carbonate is added to a hot solution of cur- 

 cumin in absolute alcohol, there is a violent effervescence, and the 

 liquid turns deep blood red. After slight concentration the excess of 

 potassic carbonate was removed by filtration, the salt precipitated with 

 ether, and purified by washing with ether. An attempt to crystallize 

 it from a mixture of alcohol and ether gave no satisfactory result. 

 Pressed between filter-paper, and then dried at 100°, it gave the 

 following results : — 



I. 0.4808 gr. of the salt gave after ignition with sulphuric acid 



0.1540 gr. of K,,SO,. 

 11. 0.5381 gr. of the salt gave 0.1680 gr. of K^SO,. 



Calculated for KC14H13O4 Found. 



I. II. 



Potassium 13.76 14.36 14.02 



KCjeHijO^ contains 12.60 per cent of potassium. 



The salt is precipitated in crimson black flocks, which dry to a mass 

 having the green color and lustre of rosanilin, although the shade is 

 somewhat blacker. It is very easily soluble in water and alcohol, 

 giving blood-red solutions, but insoluble in ether, and does not seem 

 to be altered by exposure to the air. It can also be made by the 

 action of an excess of curcumin on the dipotassic salt, or by adding 

 potassic hydrate not in excess to curcumin suspended in alcohol. It 

 is very much more soluble than the dipotassic salt. 



Curcumin forms also a flame-colored calcium salt, slightly soluble in 

 water, which can be made by adding calcic chloride to a solution of 

 the monopotassic salt. The same salt is formed in small quantity 

 when calcic carbonate is boiled with curcumin and water or alcohol, 

 carbonic dioxide beinfj set free. 



