44 Notices of the Labours of Continental Chemists. 



It then forms a black mass, which does not contain zinc. On 

 heating very slightly, even on paper, it becomes instantly 

 white, and is changed into euchronic acid. This is exactly 

 the same as with the deoxidized indigo, only vice versa with 

 regard to the colours. Wbhler therefore proposes for this 

 blue body the name of Euchron. It is soluble in ammonia 

 and the alkalies, yielding splendid purple colour ; but the solu- 

 tion decolorated with great rapidity. If a solution of proto- 

 chloride of iron be mixed with a solution of euchronic acid 

 no change is produced, but on addition of an alkali a volumi- 

 nous violet-coloured precipitate is produced, which oxidizes 

 in the air with the greatest rapidity. By the action of zinc 

 on a boiling solution of euchronic acid an almost impercep- 

 tible quantity of gas (hydrogen or ammonia) is evolved, but 

 this is doubtless a secondary product; a white powder is 

 formed in small quantity at the same time ; it appears to be 

 mellitate of zinc. A hot solution of euchronic acid forms, in 

 a dilute solution of nitrate of silver, a yellow precipitate, which 

 is dissolved again on shaking, but on cooling is deposited. It 

 is not dissolved by ammonia, but becomes changed and passes 

 milky through the filter, &c. The lead salt is obtained by 

 adding a boiling solution of euchronic acid to a dilute so- 

 lution of neutral acetate of lead. The salt is deposited on 

 cooling as a yellow powder, or in small yellow crystals. The 

 filtered fluid, if boiled, deposits white mellitate of lead. 

 Heated to 160° loses 11*36 per cent, water. Both this salt 

 (dried at 160°) and the silver salt, however, still contain water. 

 The composition of the euchronic acid is C 1 - N 3 O 6 . Atomic 

 weight 1694*29. The anhydrous silver salt is 2 Ag + C 12 N 2 

 O 6 , the hydrated 2 Ag + C 12 N 2 O 3 + H°- O. The lead 

 salt, dried at 150°, is Pb + C' 2 N 2 O + H 2 O. The cry- 

 stallized salt is Pb + O N 2 O + 5 H° O. Euchronic acid 

 heated to 200° is C 12 N 2 G 5 + 2H 2 Oj the crystallized con- 

 tains 2 atoms of water moi*e. The acid euchronate of am- 

 monia, obtained by heating the mellitate, is N 2 H 8 O + H 2 

 O . C' 2 N* O c ; it is not changed at 200°. The decomposition 

 of the mellitate of ammonia is then as follows : — Seven atoms 

 are decomposed and form 2 atoms of paramid, 1 atom of 

 euchronic acid, 4 atoms of ammonia, and 14 atoms of water. 

 2 atoms Paramid . . . . = C 16 H 4 N 4 O 8 

 1 atom Euchronic acid . . = C ,s N 9 O 6 

 4 atoms Ammonia . . . . = H i4 N 8 

 14 atoms Water = H 28 O' 4 



7 atoms Mellitate of ammonia = C 28 H 56 N 14 O 28 

 By the metamorphosis of euchronic acid by water at 200°, 



