Am.  Jour.  Pharm. 
Dec,  1889. 
Commercial  Tar. 
601 
cesses  are  very  wasteful  and  the  product  is  much  darker  than  that  pre- 
pared by  the  last  method,  which  yields  a  lighter  colored  product  of  a 
very  characteristic  tar  odor. 
Living  in  the  State  of  Georgia  and  in  a  locality  to  see  something 
of  the  manufacture  of  tar  by  the  above  mentioned  processes,  I  pro- 
cured a  sample  made  by  the  third  method,  which  nearly  represents 
the  commercial  article.  I  was  also  supplied  by  Mr.  Fletcher  with  a 
sample  made  by  the  first  process,  from  his  locality,  near  Little 
Rock,  Arkansas.  A  third  sample — "  North  Carolina  pure  pine  tar, 
refined  and  especially  adapted  for  medicinal  or  any  other  purposes," 
put  up  and  sold  by  Mr.  Good,  of  Philadelphia — was  procured  from 
the  College  Cabinet,  and  examined  with  the  other  two.  It  is  labelled 
as  coming  from  North  Carolina.  An  account  of  the  method  used  in 
refining  it  may  be  found  in  the  Amer.  Jour.  Phar.,  1889,  page 
234,  by  Dr.  C.  B.  Lowe. 
The  three  samples  were  first  spread  in  thin  layers  on  glass.  On 
holding  towards  the  light  the  refined  tar  was  found  to  be  smooth  and 
amorphous,  while  the  other  two  samples  were  shown  to  be  largely 
composed  of  granular  transparent  masses,  which  under  the  microscope 
assumed  a  crystalline  form,  showing  brilliant  effects  with  polarized 
light.  These  crystals,  according  to  Fluckiger  {Pharmacograjphia,  2d 
ed.,  page  622),  are  pyrocatechin.  The  specific  gravity  of  the  refined 
tar  was  found  to  be  1*010,  that  from  Georgia  1*083,  and  the  sample 
from  Arkansas  1*090.  The  average  specific  gravity  of  tar  from 
coniferse  is  said  to  be  1*060.  None  of  the  samples  were  completely 
soluble  in  petroleum  ether  (b.  p.  25°-40°  C).  All  were  soluble  in  95 
per  cent,  alcohol,  absolute  alcohol,  ether,  and  chloroform.  All  were 
acid  to  litmus  paper  and  imparted  an  acid  reaction  to  water.  Ten 
grams  of  each  sample  were  digested  with  water  for  forty-eight  hours, 
the  clear  aqueous  solutions,  which  had  become  yellow  in  color,  was 
separated,  agitated  with  ether,  and  the  ether  allowed  to  evaporate 
spontaneously,  when  a  brown  somewhat  oily  residue  was  obtained  in 
every  case.  The  residue  was  nearly  completely  soluble  in  water,  and 
the  aqueous  solutions  when  treated  with  ferric  chloride  gave  greenish 
colors,  with  ferric  acetate  darker  colors,  with  ferrous  sulphate  no 
change,  with  calcium  hydrate  red-brown  colors,  and  with  gelatin  no 
change.  These  tests  all  indicate  the  presence  of  pyrocatechin,  and 
judging  by  the  colors  it  was  most  abundant  in  the  Arkansas  and 
Georgia  tar,  and  almost  absent  in  the  refined  tar.    The  remaining 
