S94< Dr. Hofmann on tlie Metamorphoses of Indigo. 



from which it crystalUzes on coohng or by evaporation in re- 

 gular octahedrons, in which the axes, as in the crystals of 

 alum, have the planes of the cubes developed in a veiy high 

 degree. I have obtained completely formed crystals, the axes 

 of which were about a centimetre in length, and could be there- 

 fore submitted to the most exact crystallographic examination ; 

 they are not altered by exposure to the air. By rapidly cool- 

 ing a boiling alcoholic solution of this base, it is deposited in 

 the form of small, regular octahedrons, which present the 

 most striking resemblance to codeine. The facility with which 

 this body crystallizes is indeed remarkable; its solution yields 

 by evaporation regular crystals even to the last drop. 



This base is also extremely soluble in aether, pyro-acetic 

 spirit, acetone, bisulphuret of carbon, fatty and aethereal oils. 

 Water dissolves it but sparingly. By rapid cooling the boil- 

 ing saturated solution becomes milky; but by proceeding 

 slowly the base is deposited in vvell-defined small octahedrons, 

 possessing the lustre of the diamond. By agitation with aether 

 the base is withdrawn from the aqueous solution. Its odour 

 is pleasant, somewhat like wine ; its taste aromatic and burn- 

 ing. In both respects it cannot absolutely be distinguished 

 from aniline. The crystals melt by heat. Ob making the 

 experiment with a considerable quantity, the whole mass fused 

 at a temperature of 64° to Q5° cent, into a yellow oily liquid, 

 which solidified on cooling into a mass of large octahedrons, 

 the thermometer sinking at the same time to 57° cent. This 

 base is in the highest degree volatile. The alcoholic solution 

 cannot be evaporated without considerable loss. Even at com- 

 mon temperatures the crystals volatilize, as may be seen by the 

 white vapours which arise on bringing near them a glass rod 

 moistened with hydrochloric acid. With water the base can 

 easily be distilled. In an experiment to distil it alone, made 

 with a small quantity, I always obtained, besides the oily drops, 

 the blue product of decomposition which I have already stated 

 is formed in the preparation of the base. This decomposition 

 prevents the determination of the boiling-point, which at all 

 events hes above 200° cent. The vapour of the base burns 

 with a brilliant smoky flame, possessing the green- coloured 

 border peculiar to organic compounds containing chlorine. 



It is heavier than water, and neither alone nor in solution 

 does it exhibit the least reaction on turmeric or reddened lit- 

 mus paper. Dahlia paper is coloured of a feeble green. 



From what has been stated, it appears that chloraniline 

 almost completely corresponds in its physical properties to 

 aniline. The chief difference is that aniline is fluid at com- 

 mon temperatures, whilst the chlorinated compound is solid. 



