ON  A  NEW  PURPLE  DYE. 
569 
which  describes  the  process  for  producing  and  applying  the 
dje : — 
"  I  take  a  cold  solution  of  sulphate  of  aniline,  or  a  cold  solu- 
tion of  sulphate  of  toluidine,  or  a  cold  solution  of  sulphate  xyli- 
dine,  or  a  cold  solution  of  sulphate  of  cumidine,  or  a  mixture  of 
any  one  of  such  solutions  with  any  others  or  otjier  of  them,  and 
as  much  of  a  cold  solution  of  a  soluble  bichromate  as  contains 
base  enough  to  convert  the  sulphuric  acid  in  any  of  the  above- 
mentioned  solutions  into  a  neutral  sulphate.  I  then  mix  the 
solutions,  and  allow  them  to  stand  for  ten  or  twelve  hours, 
when  the  mixture  will  consist  of  a  black  powder  and  a  solution 
of  a  neutral  sulphate.  I  then  throw  this  mixture  upon  a  fine 
filter,  and  wash  it  with  water  till  free  from  the  neutral  sulphate. 
I  then  dry  the  substance  thus^obtained  at  a  temperature  of  100° 
centigrade,  or  212°  Fahrenheit,  and  digest  it  repeatedly  with 
coal-tar  naphtha,  until  it  is  free  from  a  brown  substance  which 
is  extracted  by  the  naphtha.  Any  other  substance  than  coal-tar 
naphtha  may  be  used  in  which  the  brown  substance  is  soluble 
and  the  coloring  matter  is  not  soluble.  I  then  free  the  residue 
from  the  naphtha  by  evaporation,  and  digest  it  with  methylated 
spirit,  or  any  other  liquid  in  which  the  coloring  matter  is  solu- 
ble, which  dissolves  out  the  new  coloring  matter.  I  then  sepa- 
rate the  methylated  spirit  from  the  coloring  matter  by  distilla- 
tion, at  a  temperature  of  100°  centrigrade,  or  212°  Fahrenheit. 
<4  To  produce  the  lilac  or  purple  color  in  the  material  to  be 
dyed,  I  add  a  strong  solution  of  the  coloring  matter  (preferring 
an  alcoholic  solution)  to  a  dilute  boiling  solution  of  tartaric  acid 
or  oxalic  acid,  and  work  the  silk,  cotton,  or  other  material 
through  it  when  cold. 
"  For  dyeing  wool  it  is  found  advantageous  to  boil  the  wool 
with  the  above  solution  and  sulphate  of  iron,  to  rinse  it  in  water, 
and  afterwards  wash  it  in  soap  and  water." 
The  colors  produced  by  the  use  of  this  new  dyeing  material 
are  not  only  very  delicate  and  beautiful,  but  they  are  perma- 
nent when  exposed  to  light.  The  same  colors  when  produced,  as 
heretofore,  from  vegetable  dyes,  were  extremely  fugitive;  so 
much  so,  indeed,  that  linendrapers  rarely  exposed  fabrics  of  such 
colors  in  their  windows. — Lon.  Pharm.  Jour,  Aug.  1859. 
