600 
Commercial  Tar. 
Am.  Jour.  Pharm. 
Dec,  1889. 
mass  without  any  separation  of  oleic  acid.  Decant  the  water  from' 
the  oleate  and  work  the  mass  with  a  horn  or  wooden  spatula  to  free  it 
from  retained  water. 
Bismuth  oleate  thus  prepared  is  a  cream  colored  mass  about  the 
consistence  of  an  ointment,  softening  at  the  temperature  of  the  body 
and  fusing  at  58°  C.  It  is  easily  decomposed  by  contact  with  metals, 
and  is  but  very  slightly  soluble  in  the  usual  solvents  for  oleates. 
COMMERCIAL  TAR. 
By  E.  G.  Dunwody. 
Contribution  from  the  Chemical  Laboratory  of  the  Philadelphia  College  of 
Pharmacy. — No.  62. 
Tar,  as  found  and  used  in  the  United  States,  is  the  product  of  the 
incomplete  combustion  of  the  fat  pine  or  Pinus  palustris  and  some 
other  pine  species.  North  Carolina  produces  most  of  the  tar  exported 
from  this  country,  although  small  quantities,  especially  for  home  con- 
sumption, are  manufactured  in  South  Carolina,  Georgia,  and  several 
other  of  the  Southern  States.  There  are  at  least  three  methods  by 
which  tar  is  made,  perhaps  the  simplest  being  that  in  which  the  wood 
is  cut  into  short  lengths,  split,  and  the  pieces  wedged  vertically  into  an 
iron  pot  so  as  to  project  some  distance  above  the  vessel.  The  whole  is 
then  inverted  over  another  iron  pot  and  the  wood  ignited,  the  flame 
rises  around  the  outside  of  the  pot,  melting  the  resin  in  the  wood 
which  is  partly  burned  on  reaching  the  flame  and  drops  down  into 
the  vessel  below.  This  process  is  employed  by  pharmacists  and 
others  who  wish  to  produce  a  small  quantity  of  tar  for  their  own 
use. 
A  second  method  adopted  for  the  same  reasons  consists  in  cutting 
the  wood  into  lengths  of  two  to  three  feet,  splitting  to  a  diameter  of 
about  two  inches  and  placing  a  number  of  these  at  the  top  of  an  inclined 
plane  of  sheet  iron  ;  on  igniting  the  wood  the  tar  runs  down  the  plane 
and  is  collected  below.  The  third  method  is  used  in  preparing  larger 
quantities  and  consists  in  cutting  the  wood  into  lengths  of  two  to 
three  feet,  splitting  it  into  billets  and  arranging  the  end  in  a  pile  six 
to  eight  feet  diameter,  covering  with  bark  and  then  with  clay.  A  fire 
is  then  kindled  on  top,  the  fuel  being  some  of  the  poor  pieces  of  pine 
and  when  the  whole  becomes  heated,  the  tar  runs  off  below  through 
an  iron  pipe  previously  inserted  for  the  purpose.    The  first  two  pro- 
