124 
OBTAINING-  PRODUCTS  FROM  TAR. 
III.  On  the  Decomposition  of  the  Ethers. 
The  ethers  are  split  by  the  same  agents  which  cause  their  for- 
mation.   Thus — 
Water  heated  to  212°  F.,  for  102  hours,  with  stearic  and  oleic 
ethers,  begins  to  split  them,  with  regeneration  of  stearic  and  oleic 
acids.  Under  these  conditions  it  does  not  act  at  all  upon  benzoic 
ether. 
Acetic  acid,  diluted  with  2  or  3  vols,  of  water,  when  in  contact 
with  stearic  ether  for  106  hours  at  212°  F.,  distinctly  acidifie  sthe 
stearic  ether  without  producing  acetic  ether  ;  it  partially  decom- 
poses butyric  and  benzoic  ethers,  with  formation  of  butyric  and 
benzoic  acids. 
Fuming  muriatic  acid,  in  106  hours,  at  212°  F.,  produces  double 
decomposition  with  acetic,  butyric,  benzoic  and  stearic  ethers. 
The  acids  are  set  free,  and  muriatic  ether  is  formed.  The  decom- 
position is  never  complete,  unless  in  the  case  of  stearic  ether. 
Thus  a  weak  acid  may  be  etherified  or  its  ether  decomposed  at 
will  under  the  influence  of  muriatic,  or  even  of  acetic  acid.  This 
difference  in  the  action  of  the  same  substance  results  from  the  pre- 
sence of  an  excess  of  water  in  the  one  case,  of  alcohol  in  the  other. 
The  mass  and  relative  energy  of  the  acids  are  also  to  be  taken  into 
account. — Chem.  Gaz.f  Jan.  1854,  from  Comptes  Rendus)  Dec.  5, 
1853,  p.  855. 
PATENT  GRANTED  TO  G.  SHAND  AND  A.  McLEAN,  FOR  IM- 
PROVEMENTS IN  OBTAINING  PRODUCTS  FROM  TAR. 
This  invention  has  reference  to  the  treatment  of  tar,  for  the 
purpose  of  extracting  its  products,  and  rendering  the  same  avail- 
able for  useful  purposes,  whether  the  tar  to  be  so  treated  be  ob- 
tained from  wood,  coal  or  animal  substances. 
In  order  to  accomplish  these  objects,  the  tar  is  submitted  to 
the  following  processes  : — In  the  first  place,  crude  or  rough  naph- 
tha and  ammonia  is  distilled  over  in  the  usual  way  from  coal  or 
gas  tar  ;  and  by  further  distillation,  "  pitch  oil,"  »  tar  oil,"  or 
«  creosote  oil  "  is  obtained,  which  the  patentees  denominate  crude 
"  naphthaline  oil."  Secondly,  this  oil  is  purified  by  means  of 
acids  and  alkalies,  in  the  manner  hereafter  described ;  and  from 
the  oil  so  purified,  the  naphthaline,  and  also  a  lighter  and  a 
heavier  oil,  is  extracted.    And,  lastly,  tar  obtained  from  wood  or 
