80 
A  Reaction  of  Phenol. 
{  Am.  Jour.  Pharm. 
t     Feb.  1, 1872. 
The  following  are  the  more  important  applications  of  Chromium 
compounds  in  the  arts  : 
1.  The  yellow  or  neutral  chromate  of  potassa,  is  the  basis  of  all 
the  other  preparations,  being  made  directly  from  the  chromic  iron. 
2.  The  red  or  bichromate  of  potassa,  is  obtained  from  the  fore- 
going salt,  and  is  extensively  employed  in  the  arts.  In  photography 
it  is  the  basis  of  most  of  the  printing  processes,  on  account  of  the 
property  which  it  has  of  rendering  gelatine  insoluble,  by  exposure  to 
light.  In  dying,  it  is  extensively  used  as  a  mordant.  It  is  the  ma- 
terial from  which  chromic  oxide,  chromic  aeid,  and  the  metallic 
chromates  are  prepared. 
3.  Chromic  oxide  is  the  most  insoluble,  green  pigment  known,  it 
is  extensively  used  in  printing  "  greenbacks,"  and  in  staining  glass 
and  painting  porcelain. 
4.  Chromic  acid  is  a  powerful  oxidizing  agent.  It  is  extensively 
used  on  this  account  in  chemical  researches,  is  found  very  useful  as 
an  exciting  fluid  in  galvanic  batteries,  was  used  for  preparing  the 
beautiful  "  mauve  red"  from  aniline,  is  employed  in  bleaching  palm 
oil,  destroying  the  empyreumatic  impurities  of  acetic  acid,  etc. 
5.  The  chromates  of  lead,  bismuth,  baryta,  strontia  and  zinc  are 
extensively  used  as  pigments,  varying  in  tint  from  the  vermillion  red 
of  the  basic  chromate  of  lead,  to  the  pale  straw  yellow  of  the  strontia 
salt.  The  common  "  chrome  green  "  is  a  mixture  of  chromate  of 
lead  and  Prussian  blue. 
6.  The  beautiful  violet  chromic  chloride,  has  recently  been  intro- 
duced as  a  cancer  remedy. 
7.  Chromium  steel,  made  by  combining  about  five  per  cent,  of 
chromium  with  cast  iron,  possesses  most  remarkable  properties.  On 
account  of  its  excessive  hardness,  it  is  the  best  metal  for  the  con- 
struction of  safes,  while  its  tensile  strength,  equal  to  a  strain  of  140,- 
000  pounds  to  the  square  inch,  specially  adapts  it  to  the  construction 
of  suspension  bridges  ;  it  was  employed  in  the  St.  Louis  bridge,  and 
will  be  used  in  the  Brooklyn  bridge. — Amer.  Chem.,  Dec,  1871,  f.  224. 
A  REACTION  OF  PHENOL. 
By  O.  Crump. 
If  a  current  of  artificial  coal-gas  be  passed  into  a  flask  containing  a 
mixture  of  equal  parts  of  phenol  and  strong  sulphuric  acid,  the  liquid 
soon  becomes  colored  and  thick,  so  that  unless  the  flask  be  gently 
