120 
ON  THE  MANUFACTURE  OF   RESIN  OTL  FROM  ROSIN. 
man  employed  in  a  turpentine  distillery  committed  the  oversight 
of  carrying  the  distillation  of  the  rough  turpentine  beyond  the 
point  at  which  the  oil  of  turpentine  had  passed  over,  the  conse- 
quence of  which  was,  that  the  resin  itself  was  decomposed  by  the 
heat,  and  resin  oil  produced.  Large  quantities  of  this  oil  are 
manufactured  in  the  neighborhoods  of  London,  Liverpool,  Hull, 
Bristol,  Glasgow,  &c  For  this  purpose,  cast-iron  stills  of  mode- 
rate dimensions,  with  copper  worms  attached,  are  usually  em- 
ployed ;  the  first  products  of  distillation  being  water,  acid,  and 
naphtha,  after  which,  on  the  application  of  an  increased  tempera- 
ture, the  resin  or  pine  oil  passes  over,  the  first  portions  of  which 
are  kept  for  mixing  with  other  oils,  whilst  the  latter  and  heavier 
oil  is  employed  in  the  manufacture  of  grease  for  lubricating  the 
bearings  of  heavy  machinery,  and  the  axles  of  railway  waggons. 
&c.  &c. 
A  good  deal  of  secrecy  was  at  one  time  maintained  respecting 
the  manufacture  of  this  oil,  and  not  a  few  unscientific  persons  paid 
dearly  for  their  acquaintance  with  some  who  had  obtained  a  know- 
ledge of  the  manufacture. 
The  best  method  of  manufacturing  resin  oil  is  by  the  lately 
patented  process  of  Mr.  Furck,  in  which  the  distillation  is  effected 
by  the  joint  operation  of  heat  obtained  from  an  open  fireplace,  ap- 
plied to  the  exterior  of  the  still,  and  steam-heat  applied  to  the 
interior.  For  this  purpose,  an  iron  still  of  a  suitable  capacity  is 
employed,  provided  with  a  head  and  curved  neck,  communicating 
with  a  copper  worm  by  means  of  a  moveable  joint  of  pipe  placed 
between  them.  To  the  upper  part  of  one  side  of  the  still  is  a 
man-hole,  for  introducing  the  resin,  and  removing  any  pitchy  de- 
posit from  the  still  ;  to  the  lower  part  of  the  still  an  exit  pipe  of 
ample  dimensions  is  connected,  through  which  as  much  as  possible 
of  the  residuum  of  the  distillation  is  conducted  off  at  the  close  of 
the  operation.  On  the  opposite  side  to  that  of  the  man-hole  are 
two  entrances  or  close  joints,  through  which  steam  pipes  pass 
into  the  still,  one  of  these  being  conducted  down  the  inner  side 
and  along  the  bottom  of  the  still  to  near  the  centre,  where  it  is 
curved  into  a  circular  form  around  it,  whilst  the  other,  entering  the 
still  close  above  the  former,  terminates  in  a  perforated  coil  in  the 
upper  part  of  the  still.  The  annular  terminating  portion  of  the 
team  pipe  surrounding  the  bottom  of  the  still  is  perforated  with 
