Carres  Apparatus  for  mahing  Ice. 
Am.  Jour.  Pharm. 
Jan.  2, 1871. 
THE  REMOVAL  OF  HEAT,  AND  THE  CONSEQUENT   PRODUCTION  OF  COLD.'"     It  may  be 
premised  that  the  form  of  ammonia  used  is  the  concentrated  aqua  ammonige, 
containing  26  per  cent,  of  gaseous  ammonia,  and  that  there  is  a  constant  pres_ 
sure  in  the  apparatus,  when  in  full  operation,  varying  from  8  to  13  atmospheres, 
equal  to  about  120  to  200  lbs.  to  the  square  inch. 
"The  apparatus  consists  (1)  of  a  cylindrical,  dome-topped,  vertical  boiler? 
A,  into  which  the  aqua  ammonia?  is  introduced,  part  of  which  enters  the  ex- 
changer, the  complement  and  the  absorption  vase,  to  be  described.  A  large  tube 
B,  issuing  from  the  dome  connects  it  with  (2)  the  liquefactor,  0,  (fig.  2)  which 
is  an  extensive  series  of  connected  tubes,  nearly  horizontal,  contained  in  a 
sheet-iron  tank  I),  filled  with  cold  running  water.  In  this  the  gas,  under  the 
pressure  and  the  cold,  is  liquefied,  its  latent  heat  being  carried  off  by  the  cold 
water,  whilst  the  liquefied  ammoniacal  gas  passes  out  at  the  lowest  end  by  a  small 
tube  E,  into  (3)  the  recipient,  F,  where  it  collects.  This  vessel  is  connected 
by  a  tube  with  (4)  the  distributing  valve,  G-,  through  which  the  liquefied  ammo- 
niacal gas  expands  into  four  stacks  of  zig-zag  tubes  H,  contained  in  the  freez- 
ing cistern,  I.  The  freezing  cistern  consists  of  a  wooden  tank  lined  with  iron^ 
in  which  are  placed  four  lines  of  zigzag  tubes,  above  noticed,  into  which  the 
liquefied  ammoniacal  gas  enters  from  the  distributing  valve.  Between  these 
tubes,  twenty-four  metallic  cans,  or  freezers,  filled  with  water  are  placed,  and 
the  whole  interior  of  the  tank  is  filled  with  a  bath  of  strong  brine,  or,  prefera- 
bly, solution  of  chloride  of  calcium,  which  is  incapable  of  being  frozen  by  the 
temperature  produced,  and  is  made  to  circulate  between  the  tubes  and  freezing 
cans,  J,  J.  by  a  stirring  apparatus,  K.  These  stacks  of  zigzags  connect  at 
bottom  with  a  cylindrical  tube  called  the  collector,  L.  When  now  the  dis- 
tributing valve  is  partially  opened,  the  liquefied  ammoniacal  gas  is  forced  indue 
proportion  into  the  zigzag  tubes,  where  it  rapidly  expands  into  gas  by  the 
assumption  of  the  heat  necessary  for  its  vaporization  from  the  surrounding  brine, 
which  in  its  turn  abstracts  the  heat  from  the  water  in  the  cans,  (by  virtue  of  which 
only  it  can  retain  its  fluidity),  and  thus  converts  it  into  ice,  and  accomplishes 
the  chief  purpose  of  the  machine.  But  the  apparatus,  acting  continuously,  now 
gathers  the  resulting  ammoniacal  gas,  redissolves  it  in  the  weak  aqua  ammo- 
ni{3e  of  the  boiler  which  it  has  previously  abstracted  and  cooled,  and  then  re- 
turns it  to  the  boiler  to  be  again  deprived  of  its  gas.  This  remarkable  com- 
pound result  is  effected  in  this  wise  :  The  ammoniacal  gas,  after  performing  its 
office  of  rendering  latent  the  sensible  heat  of  the  water,  passes  on,  first  to  the 
collector,  L,  and  from  this  through  a  tube,  to  the  absorption  vase,  M,  (fig.  2, 
which  consists  of  a  cylindrical  vessel  enclosing  a  tall  coil  of  tube,  N,  N,  through 
which  passes  a  constant  current  of  cold  water),  and  there,  after  the  machine 
has  been  working  some  time,  it  meets  with  the  exhausted  aqua  ammonise, 
by  which  it  is  rapidly  absorbed,  and  which  thus  regains  its  original 
strength.  The  manner  in  which  the  weak  aqua  ammonias  reaches  the 
absortion  vase  M,  and  the  regenerated  aqua  ammonise  is  returned  to 
the  boiler  A,  all  of  which  has  been  effected  under  pressure  varying  frem  8 
to  13  atmospheres,  is  as  follows  :  By  a  tube  O,  reaching  from  the  bottom  of  the 
boiler,  the  latter  is  connected  with  the  coil  of  the  exchanger,  P,  which  con- 
