JACKSON AND PHINNEY. — PICRYLMALONIC ESTER. 109 



With salts of lead heavy dark red flocks. 



Salts of the other metals gave precipitates as a general rule, but they 

 were not characteristic. The behavior with argentic nitrate, however, 

 should be especially mentioned, as this gave no precipitate in dilute solu- 

 tions, and only a slight cloudy dark red one when the solutions were strong. 

 The barium, zinc, and copper salts were analyzed. 



Barium Salt. — This salt was made by adding a solution of baric 

 chloride to the aqueous solution of the ammonium salt. The heavy 

 purple flocks thus obtained were washed with water, dried at 100°, and 

 analysed with the following result : — 



0.4864 gram of the salt gave 0.1236 gram of baric sulphate. 



Calculated for 

 [C8Hj(N0j)3C(C00CoIl5)2JjBa. Found. 



Barium 15.62 14.95 



The salt is so hygroscopic that two tenths of a gram will gain as' much 

 as four milligrams during the time of weighing, if it is in an open watch 

 glass. In evaporating it with sulphuric acid for analysis, care must be 

 taken not to apply the heat too suddenly at first, or an explosion may 

 result. The best plan is to heat the mixture for some time to 100", as 

 then the decomposition goes on quietly. 



Properties. — The barium salt appears as a purple obscurely crystalline 

 mass, essentially insoluble in water. It explodes if heated to 120°. 



Zinc Salt. — This salt was made by mixing solutions of zincic sulphate 

 and the ammonium salt of the ester. It was purified by washing, dried 

 at 100°, and analyzed with the following result: — 



0.4869 gram of the salt gave 0.0478 gram of zincic oxide. 



Calculated for 

 [Coll, NOolsCICOOOall,-, o „Zrx. Found. 



Zinc 8.07 7.88 



Properties. — The zinc salt forms a reddish brown crystalline mass, 

 essentially insoluble in water, but very hygro>copic. Like the barium salt 

 it explodes easily, if heated with strong sulphuric acid, and therefore the 

 same precautions must be used in analyzing it which were recommended 

 in the case of the barium salt. 



Copper Salt. — This salt was made by mixing aqueous solutions of 

 cupric sulphate and the ammonium salt of the ester. It was purified by 

 washing with water, and after drying at 100° gave the following result 

 on analysis : — 



0.3012 gram of the salt gave 0.0291 gram of cupric oxide. 



