The  oil  obtained  is  treated  with  dry
ammoniacal  gas,  whereby  naphthaline
is  deposited,  then  filtered  through  a
bag,  tne  filtrate  forming  the  purified,
heavy  coal-tar  oil.  The  lighter  coal-
tar  oil,  having  a  specific  gravity  of  0.91,
is  compounded  in  another  distilling  ap-
paratus with  2  pounds  of  burned  lime
to  1  gallon  of  oil,  then  allowed  to
stand  for  some  time,  and  finally  dis-
tilled. The  product  will  be  a  more
volatile  oil,  which  can  be  rectified  by
means  of  superheated  steam,  and  used
together  with  varnish  oil.
Manufacture  of  Yellow  Shoemaker's
Wax  from  Purified  Coal-tar  Oils,
Melt  400  pounds  of  rosin  in  a  cast-iron
boiler  over  a  moderate  fire,  add  grad-
ually 40  pounds  of  purified,  heavy  rosin
oil  and  a  like  quantity  of  purified,  heavy
coal-tar  oil  free  from  creosote,  and  con-
tinue boiling  over  a  moderate  fire  until
a  sample  taken  from  the  boiler,  on  cool-
ing, can  be  kneaded  and  drawn  between
the  fingers.  Now  let  the  mixture  cool,
and,  while  it  is  in  a  liquid  state,  add  a
.  mixture  of  20  pounds  each  of  cnrome-
yellow  and  chalk,  mix  thoroughly  and
pack  the  pitch,  which  is  now  com-
mercial shoemaker's  pitch,  in  boxes.
