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PAINTING  WITH  OXYCHLORIDE  OF  ZINC. 
ON  A  NEW  PROCESS  FOR  PAINTING  WITH  OXYCHLORIDE  OF 
ZINC. 
By  M.  Sorel. 
In  1855  I  had  the  honor  of  presenting  to  the  Academy  vari- 
ous products  obtained  by  means  of  oxychloride  of  zinc,  especi- 
ally cements  and  mastics,  as  hard  as  marble  and  quite  insoluble 
in  water,  and  a  paint,  equally  insoluble,  intended  to  replace, 
very  economically,  oil  and  other  painting.  This  paint  had  the 
inconvenience  of  being  difficult  to  use,  and  of  requiring,  like 
siliceous  painting,  the  application  of  a  liquid  on  the  last  layer 
to  fix  it  and  render  it  insoluble  ;  when  I  wished  to  avoid  the  use 
of  this  liquid  by  rendering  my  paint  more  drying,  I  was  met  by 
an  equally  serious  inconvenience  :  the  paint  thickened  very  rapid- 
ly in  the  vessel,  and  there  was  not  time  to  use  it.  I  have  now 
succeeded,  by  adding  certain  substances  to  my  liquid,  in  sur- 
mounting these  difficulties,  and  rendering  the  application  of  this 
new  paint  easy. 
The  liquid  which  in  this  paint  replaces  oil,  essence  of  turpen- 
tine, and  the  other  liquids  and  excipients  used  in  ordinary  paint- 
ing, is  an  aqueous  solution  of  chloride  of  zinc,  in  which  I  have 
dissolved  an  alkaline  tartrate.  These  salts  possess  in  the  high- 
est degree  the  property  of  retarding  the  thickening  of  the  new 
paint  before  being  used.  I  add  to  the  liquid,  to  give  tenacity  to 
the  paint,  gelatine  or  fecula,  which  I  have  caused  to  pass  into 
the  state  of  starch  by  heating  the  liquid.  It  must  not  be  heated 
so  much  as  to  transform  the  fecula  into  dextrine  or  glucose. 
To  form  the  new  paint,  whatever  the  color  may  be,  I  use  the 
above  liquid,  and  a  powder  which  should  be  in  great  part  oxide 
of  zinc.  For  colored  paints  I  use  the  same  powder  plus  the 
coloring  matters.  The  colors  usually  employed  in  ordinary 
painting  may  be  employed. 
The  new  paint  possesses  the  following  properties :— 1st.  It  is 
not  necessary  to  grind  it ;  the  powder  only  requires  to  be  diluted 
with  the  liquid,  and  the  paint  is  used  in  the  ordinary  manner. 
2nd.  It  is  more  beautiful  and  solid  than  oil  paint;  it  covers 
better  and  is  not  rendered  black  by  sulphurous  emanations,  like 
paints  of  ceruse  or  other  lead  bases.  3rd.  It  is  absolutely  with- 
out odor,  and  dries  very  rapidly.    We  can  apply  a  layer  every 
