268 
ON  COLOR  OBTAINED  FROM  COAL  TAR  PRODUCTS. 
patient  passed  a  good  night,  and  felt  better  ;  the  urine  was  not 
so  scanty,  but  high-colored.  Nausea  and  headache  continued ; 
no  appetite.  In  three  weeks  the  patient  had  quite  recovered, 
and  was  able  to  resume  his  customary  occupation. — Journal  de 
Pharmacie  et  de  Qhimie,  Nov.,  1857,  from  the  London  Chemist, 
Feb.,  1858. 
ON  COLOR  OBTAINED  FROM  COAL  TAR  PRODUCTS. 
By  Professor  F.  Crace  Caltert. 
When,  in  November,  1854,  I  had  the  honor  to  read  before  the 
Society  of  Arts  a  paper  on  the  products  obtained  from  coal,  I 
stated  that  ere  long,  besides  carbo-azotic  acid,  some  valuable 
dyeing  substances  would  be  prepared  from  this  mineral.  This 
expectation  has  been  fulfilled.  Messrs.  W.  Perkins  and  A.  H. 
Church  have  obtained  several  blue  coloring  substances  from  the 
alkaloids  of  coal  tar,  and  one  from  napthaline,  named  by  them 
Nitroso-phenyline  and  Nitroso-naphthaline,  &c. 
Mr.  Perkins  has  lately  taken  out  a  patent  for  the  commercial 
application  of  some  of  these  beautiful  purple  blue  colors,  which 
he  has  succeeded  in  fixing  on  silk,  a  sample  of  which  I  have  the 
pleasure  to  lay  before  you.  This  fine  color,  which  rivals  the 
delicate  and  admired  color  of  orchil,  has  this  great  advantage 
over  it,  that  it  is  not  destroyed  by  light ;  Mr.  Perkins  has, 
therefore,  solved  one  of  the  problems  of  the  art  of  dyeing,  viz., 
the  production  of  a  fast  color  similar  to  the  fugitive  one  of  orchil. 
Mr.  Perkin's  process  consists  in  dissolving  in  water  the  sulphates 
of  aniline,  of  cuminine,  and  of  toluidine,  and  adding  a  quantity 
of  bichromate  of  potash  sufficient  to  neutralize  the  sulphuric  acid 
in  these  sulphates.  The  whole  is  left  to  stand  for  twelve  hours, 
when  a  brown  substance  is  precipitated,  which  is  washed  with 
coal  tar  naphtha,  and  then  dissolved  in  methylated  spirits.  This 
solution,  with  the  addition  of  a  little  tartaric  or  oxalic  acid, 
forms  the  dyeing  liquor  of  Mr.  Perkins. 
Mr.  Charles  Lowe  and  myself  have  lately  been  fortunate 
enough  to  obtain  from  coal  tar,  products  having  a  most  extra- 
ordinary dyeing  power,  and  yielding  colors  nearly  as  beautiful 
as  safflower  pinks  and  cochineal  crimsons  ;  and  what  increases 
