APPARATUS  FOR  PREPARING  ETHER  BY  STEAM. 
389 
round  within  the  hollow  cylinder  to  get  exit,  as  vapor  by  u,  or 
condensed  by  y  and  z,  these  three  outlets  being  upon  the  side 
of  the  vertical  partition  opposite  to  the  inlets.  The  condensers 
are  each  furnished  with  three  sheet  iron  feet  about  3  inches  high, 
upon  which  they  stand,  and  by  which  they  are  fastened  by  screws 
to  the  bottoms  of  the  tubs.  All  the  tubes  and  passages  are  made 
large  to  provide  for  the  slow  circulation  of  the  vapors,  as  this 
slow  circulation  is  the  important  point  in  condensation. 
The  still  as  described,  including  the  thermometer  and  "globe 
valve,"  cost  45  dollars,  and  the  remainder  of  the  apparatus,  ex- 
cept the  Liebig,  which  is  for  general  use,  cost  about  40  dollars, 
or  less. 
The  best  practical  charge  and  proportions  of  materials  at 
which  I  have  as  yet  arrived,  for  this  still  are, 
Of  Alcohol       s.g.  -820      3|  galls.  =  23  lbs.  12  oz.  av. 
«  Sulph.  Acid  «    1-846     2J    «     =  34   «     3  «  « 
This  mixture  commences  to  boil  at  260°  to  264°  with  foaming 
for  a  few  moments  at  first,  but  soon  settles  down  to  a  steady 
ebullition  at  266°,  its  true  boiling  point.  As  far  as  my  ex. 
perience  goes,  this  266p  is  the  most  economical  temperature  for 
etherification  with  such  materials.  Hence,  a  coincidence  between 
the  boiling  point  of  the  mixture  (and  a  mixture  "can  be  made, 
that  will  boil  at  any  desired  point  between  176°  and  620°)  and 
the  best  temperature  for  etherification  is  the  desideratum  in  this 
process.  A  mixture  like  that  of  the  U.  S.  P.,  which  boils  much 
below  the  temperature  for  etherification,  drives  over  much  un- 
decomposed  alcohol ;  whilst  a  mixture  whose  boiling  point  is 
much  above  the  point  of  etherification,  produces  more  light  oil 
of  wine  and  olefiant  gas. 
The  above  mentioned  charge,  at  a  distance  of  16  feet  (of  con- 
ducting pipe)  from  the  steam  boiler,  is  easily  kept  boiling  with  a 
pressure  of  40  lbs.  to  the  square  inch  in  the  boiler,  and  although 
the  process  will  go  on  well  with  a  pressure  of  35  lbs.,  yet  not  so 
conveniently  or  rapidly. 
At  least  18  gallons  of  alcohol  may  be  fed  economically  into  this 
charge  in  12  hours,  and  about  14  gallons  of  crude  ether  of  s.  g. 
•747  obtained.  The  alcohol  and  ether  obtained,  beside,  from  the 
first  condenser,  will  be  equal  in  value  to  the  acid  and  half  the 
fuel.  Such  is  a  rough  estimate  of  the  crude  products  of  one 
day's  work. 
