Dr. Hofmann on the Metamorphoses of Indigo. 393 



nitric acid and precipitated by nitrate of silver, gave 0*31 5 grm. 

 of chloride of silver. 



IV. The determination of the nitrogen was made in an at- 

 mosphere of carbonic acid. 0*597 grm. of substance burned 

 with peroxide of copper gave, at 334'" barom. and 11° cen- 

 tigrade, 58' cub. cent, of nitrogen. These numbers corre- 

 spond to the following per-centage: — 



I. II. III. IV. 



Carbon* =55-88 56*49 



Hydrogens 4*89 5*15 



Chlorine = 27*45 



Nitrogen = 11*38 



These numbers may be expressed in the following formula, — 



Ci2 < Q^^ >N, as is shown by comparison of the numbers 



calculated and found. 



To control this formula, I prepared the platinum double 

 salt, which crystallized beautifully, and, after drying at the 

 temperature of the air, analysed it. 0*5095 grm. of this salt, 

 after combustion, left 0*1495 grm. = 29*34 per cent, of pla- 

 tinum; the atomic weight found from this= 1626*85; theore- 

 tical atomic weight =1594*69. The agreement between the 

 two is sufficiently near. 



By adopting the formula Cjg^ /-,? > N, which is completely 



established by the analyses of the different salts and the pro- 

 ducts of decomposition of the base, the formation of this body 

 can be explained in the most satisfactory manner. It is, as 

 was to be expected, completely analogous to the formation of 

 aniline from isatine, as is shown by the following formulae : — 



Ci8{^f}N04+4(KO,HO)=C,2{cf}N + 4(C02KO)+2H. 



Chlorisatine. Chloraniline. 



I shall return afterwards to the origin of the ammonia in 

 the last stage of the preparation. 



b. Properties of Chloraniline. 



I have already stated that this base is soluble in alcohol, 

 * Carbon = 75. Hydrogen = 12-5. 



