Am'No°vri884arm'}    Pharmaceutical  Still  and  Vapor  Condenser.  565 
dangerous  explosions;  while  in  the  evaporation  of  alcohol  and  chloro- 
form the  loss  sustained  was  considerable.  This  caused  me  to  adjust 
it  in  a  manner  which  I  will  demonstrate  in  the  apparatus  here  ex- 
hibited. 
To  a  water-bath,  a,  containing  water,  a,  fitted  with  a  water-gauge,  c, 
and  faucet  to  admit  turning  off  to  keep  the  steam,  or  by  turning 
on  to  let  steam  escape,  or  to  add  water  as  needed,  and  having  proper 
handles  to  facilitate  its  removal,  is  fitted  a  tinned  copper  evaporating 
dish,  b,  as  tightly  as  possible  to  prevent  the  escape  of  steam  at  the 
sides.  The  evaporating  dish  has  on  its  sides  a  groove,  d,  as  a  receptacle 
for  a  flange  from  the  outside  cone  of  the  condensing  hood.  The  hood 
itself  is,  like  the  rest  of  the  apparatus,  made  of  light  weight  tinned 
copper,  and  consists  of  two  cones  placed  parallel  within  each  other, 
about  one  inch  apart.  The  two  cones  are  closed  squarely  at  the  bottom, 
the  outer,  I,  projecting  and  dipping  down  to  form  the  flange  for  the 
water-joint  to  fit  into  the  groove  heretoforementioned.  Running  from  the 
top  on  the  outside  of  the  outer  cone  is  a  supply  pipe,/,  for  cold  water, 
which  enters  into  the  space  between  the  two  at  the  bottom  of  the  out- 
side ones.  From  the  top  of  the  outer  cone  extends  a  pipe  of  the  same 
diameter  as  the  former  to  admit  the  escape  of  the  water  at  g.  The 
water  for  cooling  is  conducted  to  /  by  a  rubber  tube  from  a  hydrant  or 
reservoir,  and  allowed  to  flow  off  by  a  tube  again  into  a  sink  or  recep- 
tacle, or,  as  I  have  often  done  when  sufficiently  cool,  into  another 
similar  apparatus  for  further  condensing  purposes.  When  in  operation 
the  vapors  arising  from  the  evaporating  dish  will  be  condensed  on  the 
