Am.  Jour.  Pharm. 
May,  1889. 
Refined  Tar  of  Commerce. 
235 
of  the  tar  leaks  out,  and  the  water  takes  its  place.  He  also  stated  that 
at  ordinary  temperatures  the  tar  and  water  in  the  vat  would  remain 
mixed,  but  at  the  temperature  to  which  they  are  heated,  which  is  below 
the  point  at  which  the  oil  of  tar  would  be  driven  off,  they  separate  and 
the  water  rises  to  the  top.  Xo  coal  tar  is  added,  its  cost  being  equal 
to,  or  greater  than  that  of  tar,  and  its  presence  being  easily  detected 
by  taste  and  smell. 
The  color  of  tar  varies;  at  different  times  of  the  year  it  seems  to  run 
lighter  in  color  and  thinner.  The  amber  tar  is  preferred  by  some, 
especially  the  manilla  rope  manufacturers. 
Mr.  Good  seems  to  think  that  the  tar  which  he  is  supplying  is  of  a 
better  quality  than  that  formerly  on  the  market.  I  suggested  to  him 
that  his  label  was  misleading  and  that  it  would  be  better  to  change  it 
to  "  tar  refined  by  steam  heat." 
In  an  interview  since  had  with  Mr.  Edwin  H.  Rowley,  who  has 
been  for  many  years  one  of  the  largest  dealers  in  tar  and  its  products 
in  this  city,  he  states  that  the  color  of  the  tar  depends  altogether  upon 
the  mode  of  its  manufacture.  When  the  drafts  are  so  shut  off  that 
the  combustion  proceeds  slowly,  then  the  tar  resulting  therefrom 
will  be  of  an  amber  color,  of  less  density,  and  contain  more  oil  of  tar. 
But  if  the  combustion  is  forced  the  wood  will  be  carbonized  to  a  greater 
extent,  and  the  tar  will  be  of  a  darker  Color  and  thicker.  He  considers 
the  amber-colored  tar  of  superior  value.  In  distilling  the  oil  from 
the  tar,  water  first  comes  over,  then  the  oil  of  tar  which  is  collected 
and  sold  under  the  name  of  spirits  of  tar,  and  finally  a  product  which 
is  very  thick,  oily,  and  chills  easily,  for  which  there  is  little  sale.  He 
states  that  much  of  the  oil  of  tar  on  the  market  is  a  solution  of  tar  in 
rosin  oil  naphtha,  and  should  not  be  used  for  medicinal  purposes. 
Mr.  R.  also  stated  that  the  presence  of  water  in  the  barrels  of  tar 
originates  from  want  of  care  in  manufacturing  the  tar  and  filling  the  bar- 
rels. The  tar  produced  by  the  slow  combustion  of  the  wood  runs  into 
a  shallow  ditch  which  leads  into  a  pit  dug  in  the  sand ;  there  it  often 
remains  uncovered,  and  exposed  to  storms;  when  the  barrels  are  filled 
but  little  care  is  taken  to  separate  the  water.  When  a  barrel  contain- 
ing tar  is  placed  in  the  water,  the  staves  swell  so  that  the  tar  cannot 
get  out  or  the  water  in.  Large  quantities  of  tar  are  brought  from 
AVilmington,  ]ST.  C,  upon  lumber  rafts,  the  lower  tier  of  the  barrels 
being  often  partly  under  water,  thus  causing  to  some  extent  the  popu- 
lar impression. 
