Clifton College ScienCific Societi/.' 113 



Aniline red, or rosaniline, next enga,<?es our atti.tion. The most 

 advantageous mode of preparation is^he following : -A mixtureof 

 twelve parts of dry arsenic acid (As, 0^) and 10 parts of anil in p t 

 heated to about 120° C with water^or-severvl 1,0.2 Th Zi S 

 a hard mass possessing the lustre of bronze.' '1:0 separate it fiom -inv 

 unchanged anihne it is boiled with sodium hydrl^and fil ered^ 

 \ft? f I^^'PUate, weak acid is added, which disso ves rosanHine 

 leaymg the tarry matter. The compounds of this salt, with fe a oS 

 of acKl, urmsh a very intensely c-oloured red solution in w7e?^ 

 Hoffman has shown that pure aniline is incapable of furnishiio- JI lin^ 

 red, and that toluidine and aniline must be present. '"""'^'°° ''^''^'°" 



Aniline blue is obtained by di-esting rosaniline with an excess of 

 anihne; it js purified much in the same way as the wo pS nJ 

 colours The most important of these colours a e Those kn o^ 



or "S'tSs'Jlf "'i^i"^" "r'' ';■ "°'™™ of "carbolic acid - 



