ADecJemberP%or6r!J  )        United  States  Army  Laboratory.  569 
being  formed  instead;  on  the  other  hand,  if  it  rises  above  1600  C.  - 
(3200  F.)  the  contents  of  the  retort  are  not  only  liable,  but  will 
almost  inevitably  froth  over,  and  the  material  becomes  an  absolute 
loss.  The  best  results  were  obtained  if  the  temperature  did  not 
vary  much,  one  way  or  the  other,  from  155*5°  C.  (3120  P.)  The 
distillation  of  heavy  oil  of  wine  being  a  practically  daily  task,  at 
least  for  a  long  period,  the  first  duty  in  the  morning,  and  the  last  in 
the  evening,  was  connected  with  it.  The  retorts,  if  not  cleaned  the 
evening  before,  for  which  frequently  there  was  no  time,  were  emptied 
and  carefully  cleaned,  so  as  not  to  leave  as  much  as  a  speck  of  the 
carbonaceous  product  of  decomposition,  which  sometimes  encrusts 
parts  of  the  inner  walls,  in  them  ;  for  it  was  found  that  the  presence 
'of  such  was  very  likely  to  cause  the  frothing  over  of  the  contents 
during  the  distillation.  Having  then  been  thoroughly  rinsed  and 
drained,  and  dried  on  the  outside,  they  were  placed  on  a  thin  layer 
of  sand  in  the  sand  bath,  and  filled  through  the  tubulure  with  the 
previously  prepared  mixture  of  strong  alcohol  and  concentrated 
sulphuric  acid  to  within  an  inch  of  the  neck.  Sand  was  then  poured 
into  the  bath,  reaching  to  about  three-fourths  the  height  of  the  body 
of  the  retort,  the  thermometer  inserted  into  the  tubulure,  the  con- 
nection made  with  the  condenser,  this  with  the  tubulated  receiver, 
and  the  latter  with  a  tube  leading  into  the  chimney  flue,  by  means 
of  a  rubber  tube  attached  to  a  glass  tube  extending  from  the  tubulure. 
All  these  connections  were  carefully  wrapped  with  moist  bladder,  to 
secure  them  from  leakage  ;  for  during  the  reaction  there  is  an 
abundance  of  sulphurous  acid  developed,  the  inhalation  of  which 
must  be  avoided,  not  to  speak  of  loss  of  product  by  escape  from 
improperly  secured  connections.  A  glance  at  Fig.  6  will  show 
this  arrangement  better  than  can  be  done  by  description.  Heat 
was  now  applied  so  that  the  temperature  might  rise  as  rapidly  as 
possible  to  15  50,  and  then  constant  vigilance  was  necessary  to 
maintain  this  temperature  as  near  as  possible,  by  the  expedients 
previously  mentioned.  This  is  illustrated  in  the  half-tone  illustra- 
tion (Fig.  7)  in  which  the  operator  is  evidently  engaged  in  exam- 
ining the  thermometric  indication.  During  the  progress  of  this 
distillation  a  small  quantity  of  liquid  will  collect  in  the  receiver 
before  there  is  any  ebullition  ;  then,  when  the  proper  temperature  is 
reached,  the  contents  will  simmer  gently ;  presently  little  black, 
frothy  bubbles  will  make  their  appearance,  and  soon  the  entire  sur- 
