OF ARTS AND SCIENCES. 297 



branched, like certain feathery seaweeds. From the oil which forms 

 the secondary product in its preparation, the substance crystallizes in 

 flattened prisms, often two centimeters in length, arranged in slightly 

 radiating groups. The melting point is 89°. It is essentially insolu- 

 ble in water or ligroine ; slightly soluble in cold, freely in hot methyl, 

 or ethyl alcohol ; freely soluble in carbonic disulphide, glacial acetic 

 acid, or acetone ; very freely in ether, benzol, or chloroform. Strong 

 sulphuric acid has little, if any, action on it in the cold, but dissolves 

 it slightly without change of color when hot. Strong nitric acid also 

 seems not to act upon it in the cold, but, when warmed with it, turns 

 yellow and imparts a yellow color to the drops of the melted sub- 

 stance which swim on its surface. Hydrochloric acid does not seem 

 to act on it in open vessels either cold or warm, although from analooy 

 with the corresponding monobrom compound it is fair to suppose that 

 it would decompose it if the two substances were heated to 150° in 

 a sealed tube. 



The dibromdiuitrophenylmalonic ester has well marked acid prop- 

 erties, as was to be expected from the fact that one of its atoms of 

 hydrogen is attached to a carbon atom in direct contact with two car- 

 boxylester radicals and a dinitrophenyl. An excess of sodic hydrate 

 in aqueous solution has but little action on the solid, turning it pale 

 red ; if, however, a drop of alcohol is added, it turns a very dark red 

 at once, and the salt begins to dissolve. Potassic carbonate acts in 

 much the same way. Acid sodic carbonate in aqueous solution has 

 no effect, but if alcohol is added there is a slight action shown by 

 formation of a little of the red salt. Amnionic hydrate in aqueous 

 solution has but little action, but turns red if a little alcohol is added", 

 and upon warming this mixture a deep brownish red solution is ob- 

 tained, which smells strongly of ammonia, even if an excess of the 

 ester is used in making it. It seemed to be decomposed by heating, 

 or by exjiosure to the air, so that the ammonium salt must be a very 

 unstable substance. The solution of the ammonium salt made with 

 an excess of the ester (but still smelling of ammonia) was treated with 

 various reagents, and gave the following characteristic precipitates : — 



With a salt of magnesium, calcium, strontium, or barium, very heavy 

 pale red flocks. 



With a zinc salt, pale yellow flocks. 



With a salt of manganese, cobalt, or nickel, pale red flocks. 



With & ferric salt, pale brownish purple. 



With a cupric salt, bright yellow. 



With salts of mercury, pale red. 



