126 
OBTAINING    PRODUCTS  FROM  TAR. 
the  still  is  then  run  into  a  second  vessel  (leaving  the  former  pro- 
duct of  distillation  in  the  manner  hereinafter  described) ;  and  the 
process  of  distillation  is  continued  until  the  contents  of  the  still 
are  run  off.  The  oil,  so  distilled,  is  next  treated  with  a  small 
quantity  of  caustic  ammonia,  in  a  dry  state,  for  the  purpose  of 
absorbing  any  trace  of  water  remaining  in  it.  When  the  oil  has 
been  allowed  to  settle,  and  has  undergone  filtration,  it  is  ready 
for  use,  either  alone  or  mixed  with  other  oils.  This  manufacture 
of  oil  the  patentees  denominate  "  purified  heavy  naphthaline  oil." 
The  inventors  then  take  the  former  product  of  the  distillation 
of  the  crude  naphthaline  oil  before  mentioned,  and  put  it  into 
any  convenient  still,  with  a  worm  and  condensing  apparatus  at- 
tached, and  to  every  gallon  of  oil  about  1  lb.  weight  of  caustic 
lime,  or  burnt  lime-shells,  are  added.  The  oil  and  lime,  having 
been  well  stirred  together,  are  acted  on  by  a  gentle  heat  from  a 
fire  ;  and  a  light  volatile  oil  is  distilled  over,  which  is  afterwards 
rectified  by  means  of  steam  from  a  steam-boiler,  and  passed  into 
any  suitable  still,  with  a  worm  and  condensing  apparatus  at- 
tached. This  manufacture  of  oil  is  useful  for  solvent  and  other 
purposes.  The  distillation  is  still  continued  until  the  product 
reaches  the  specific  gravity  of  about  910°,  when  a  stronger  heat 
is  applied  from  the  fire,  and  the  oil  is  run  from  the  still  into  a 
second  vessel,  the  operation  being  continued  until  the  contents 
of  the  still  are  distilled  over.  The  oil  last  distilled  is  then  allowed 
to  cool  down  to  a  temperature  of  from  30°  to  40°  F.,  when  the 
naphthaline  will  be  deposited  at  the  bottom  of  the  vessel,  and 
may  be  separated  from  the  oil  by  filtration  and  pressure.  The 
oil  from  which  the  naphthaline  has  been  separated,  and  which  is 
called  by  the  patentees  "  light  naphthaline  oil,"  is  treated  with 
magnesia  or  other  substance,  in  a  dry  state,  to  absorb  any  trace 
of  water,  and  when  filtered  is  ready  for  use.  Naphthaline  may 
also  be  obtained  by  treating  the  purified  heavy  naphthaline  oil 
with  caustic  lime,  in  the  manner  above  described.  In  order  to 
purify  the  naphthaline,  after  it  has  been  separated  from"  the  naph- 
thaline oil,  the  naphthaline  is  put  into  a  retort  or  any  convenient 
apparatus,  and  with  a  gentle  heat  it  is  sublimed  in  vapor  into  a 
wooden  chamber,  where  it  condenses  in  flakes  of  a  white  color. 
The  last  part  of  this  invention  consists  in  applying  the  series 
of  processes  above  described  to  tar  obtained  from  wood  or  animal 
substances.  For  this  purpose  the  tar  thus  obtained  is  treated  in  a 
