258 
Paraffin  Ointment. 
f  Am.  Jour.  Pharm. 
t        June,  1875. 
gravity,  to  percolate  through.  Reserve  as  much  of  the  percolate  as  is 
nearly  free  from  color,  odor  and  taste.  Pass  the  succeeding  portions 
through  a  second  percolator  arranged  in  the  same  manner,  and  when 
this  ceases  to  decolorize  and  deodorize  sufficiently,  pour  those  portions 
which  have  already  passed  through  the  first  and  second  percolators 
upon  a  third  one.  At  every  operation  reserve  those  first  portions  of 
oil  which  are  very  light  in  color,  and  nearly  devoid  of  the  petroleum 
taste  and  smell.  Add  16  parts  of  this  purified  oil  to  one  part  of  best 
white,  hard  paraffin,  which  has  been  previously  melted  by  means  of  a 
water-bath. 
Notes  on  the  above  Process. — The  melting  point  of  the  paraffin  used 
was  140°  F.  That  having  a  lower  fusing  point  will  probably  answer 
■quite  as  well,  if  the  amount  is  increased  proportionally.  The  applica- 
tion of  direct  heat  must  be  carefully  avoided  in  every  step  of  the  pro- 
cess. Whenever  it  becomes  necessary  to  melt  the  ointment  subse- 
quently, this  should  always  be  done  with  the  assistance  of  a  water-bath. 
The  color  of  the  ointment  will  vary  somewhat  with  the  care  used  in 
the  purification  of  the  oil.  By  very  slow  and  careful  repercolation  it 
may  be  obtained  almost  colorless. 
It  is  quite  possible  that  the  residuum  of  other  oil  wells  may  be  equally 
appropriate  for  this  purpose,  but,  of  those  experimented  with,  none 
were  found  that  could  be  so  conveniently  purified  as  that  of  the  Smith's 
Ferry  Well,  and  the  so-called  cosmo-lubricating  oil.  The  Smith's 
Ferry  Well  is  located  on  the  Ohio  river,  between  Pittsburgh  and  Wells- 
ville,  Ohio.  We  are  informed  that  the  crude  oil  obtained  from  it  varies 
in  gravity  from  46°  to  48°  Beaume.  The  German  edition  of  "  Mus- 
pratt's  Chemistry,"  published  in  1868,  specially  mentions  this  oil  on 
account  of  its  clearness,  transparency  and  freedom  from  sulphur,  phos- 
phorus and  arsenic  compounds,  to  which  the  penetrating  and  offensive 
odor  of  ordinary  crude  coal  oils  is  attributed. 
The  natural  Smith's  Ferry  oil  yields  from  15  to  20  percentum  of 
residuum,  after  the  benzin  and  burning  oils  have  been  removed  by 
distillation.  This  residuum  is  rectified  by  treatment  with  from  10  to 
1 5  percentum  of  sulphuric  acid,  succeeded  by  sufficient  caustic  soda  to 
neutralize  it  completely.  All  traces  of  chemicals  are  carefully  re- 
moved by  washing  the  oil  three  or  four  times  successively  with  hot 
water.  Its  chief  consumption  is  as  an  engine  and  cylinder  oil,  for 
which  purposes  it  is  very  important  that  none  of  the  acid  is  left  adher- 
ent to  it.    The  same  residuum  is  also  rectified  in  Elmira,  New  York, 
