52 
PHOSPHORUS  GLUE  AND  CHLORIDE  OF  AMMONIUM. 
The  receivers  used  are  made  of  ordinary  clay  with  lead  glaze' 
and  consist  of  two  parts  :  a  cylindrical  vessel,  n  n,  and  a  lid,  o  <?? 
with  an  open  neck,  p,  and  a  tube,  q,  four  or  five  inches  long,  of 
such  diameter  as  to  receive  the  neck  of  the  retort,  and  extending 
below  the  under  surface  of  the  lid,  so  as  to  dip  into  water  con- 
tained in  the  cylindrical  vessel.  These  receivers  are  cheaper 
than  those  made  of  copper,  which  are  soon  destroyed  by  the 
action  of  the  hot  phosphorous  vapor,  and  the  gases  generated 
in  the  operation. 
When  the  retorts  have  been  arranged  in  the  furnace,  and  the 
receivers  charged  with  water  connected,  the  fire  is  kindled,  and 
very  gradually  increased  during  six  or  eight  hours.  During  this 
time,  water  and  sulphurous  acid  vapors  are  given  off,  and  when 
combustible  gas  begins  to  issue  from  the  retorts,  the  connection 
with  the  receiver  is  made  tight  with  loam,  leaving  a  very  small 
hole  for  the  escape  of  gases.  An  iron  ladle,  r,  is  then  placed  in 
each  receiver,  and  the  heat  is  raised  sufficiently  to  carry  on  the 
distillation  of  the  phosphorus.  The  progress  of  the  distillation 
is  best  observed  by  raising  the  iron  ladles  from  time  to  time, 
emptying  their  contents  under  the  water  in  the  receiver,  and 
again  replacing  them,  so  as  to  catch  the  phosphorus  as  it  comes 
over.  During  the  whole  operation  combustible  gas  issues  from 
the  small  hole  in  the  luting,  and  burns  with  a  blue  flame.  When 
this  evolution  of  gas  ceases,  it  may  be  owing  to  a  stoppage  in 
neck  of  the  retort,  by  the  deposition  of  oxide  of  phosphorus.  In 
this  case  the  receiver  must  be  removed,  and  a  stout  iron  wire 
passed  up  the  neck  of  the  retort.  When  the  neck  of  the  retort 
is  found  to  be  clear,  the  stoppage  of  the  gas  must  be  owing  to 
the  retort  being  cracked, 
After  the  heat  has  been  maintained  for  forty-six  hours,  and 
finally  raised  to  near  whitenes3,  the  quantity  of  phosphorus  that 
passes  over  decreases  so  much,  that  it  is  not  worth  while  to  con- 
tinue the  operation.  The  receivers  are  then  removed,  and  the 
phosphorus  emptied  into  a  vat  under  water.  When  the  furnace 
has  cooled,  the  retorts  are  taken  out,  and  a  fresh  charge  intro- 
duced. Each  retort  contains  about  seven  or  eight  pounds  of  the 
dry  mass,  and  yields  eleven  or  twelve  ounces  of  phosphorus. 
During  the  whole  operation  the  water  in  the  receivers  must  be 
kept  cold,  without  leaving  the  lower  mouth  of  the  tube  g  un- 
covered. 
