NOTICE  OF  M.  Carre's  apparatus  for  making  ice.  105 
replace  the  weak  liquor  in  the  boiler.  The  weak  liquor  is  then 
perfectly  cooled  as  it  passes  through  the  complement  coil,  which 
is  surrounded  by  very  cold  water,  and  it  enters  the  absorption 
vase,  rapidly  absorbing  the  gas  entering  from  the  collector,  and 
reproducing  aqua  ammoniae.  Simultaneously  the  forcing  pump 
of  the  machine  is  drawing  the  cool  strong  ammonia  from  the 
upper  stratum  in  the  absorption  vase,  and  forcing  it  into  the  cyl- 
inder of  the  exchanger,  where,  after  performing  its  office  of  cool- 
ing the  weak  liquor  and  becoming  itself  heated,  it  passes  into 
the  boiler  near  its  top,  impinging  on  a  series  of  porous  dia- 
phragms of  metal  suspended  in  the  upper  part  of  the  still,  to 
facilitate  the  rapid  separation  of  the  gas  a  second  time.  Thus 
it  is  apparent  that  the  same  aqua  ammonias  may  be  used  over 
and  over  again,  to  an  extent  only  limited  by  the  perfection  of 
the  joints  under  the  great  pressure  constantly  existing. 
At  starting  the  machine,  all  the  cans  are  filled  with  pure 
water  and  closely  covered  with  wooden  lids,  and  when,  after 
about  four  hours,  they  are  frozen,  the  operator  removes  the  ice 
from  the  first,  third,  fifth,  seventh,  &c.,  one  every  five  minutes, 
until  he  has  reached  i\iQ  forty-seventh,  refilling  each  with  water 
and  returning  it  to  its  place  as  he  goes,  when  he  takes  the 
series  two,  four,  six,  eight,  ten,  &c.,  to  the  forty-eighth,  in  the 
same  way,  when  the  other  series  is  re  commenced,  and  so  on  day 
and  night,  making  three  tons  every  twenty-four  hours.  Mr. 
Bujac  says  that  on  the  24th  of  October,  1869,  an  experiment 
with  this  machine  yielded  2204  lbs.  in  eight  hours,  with  a  gain 
of  11°  C,  the  bath  being  6°  below  zero  0.  at  8  o'clock,  A.  M., 
and  17°  C.  below  zero  at  4  o'clock,  P.  M.  ;  and  he  thinks  the 
product  would  reach  7000  to  7500  lbs.  in  twenty-four  hours  if 
the  boiler  and  tubes  were  covered  with  felt.  To  remove  the  ice, 
the  cans  are  dipped  momentarily  in  hot  water,  and  then  inverted. 
The  cakes  are  uniformly  rectangular,  and  as  their  temperature 
when  removed  is  far  below  32°  F.,  by  simply  moistening  their 
surface  they  cement  perfectly  to  each  other,  and  form  solid 
blocks  of  ice  of  any  required  dimensions. 
Mr.  Bujac  had  a  shallow  tank  of  wood,  ten  feet  by  thirty  feet, 
arranged  with  a  series  of  iron  pipes  just  below  the  surface  of  the 
water  it  contained,  when  on  attaching  the  machine  the  water  was 
