106  REACTION  BETWEEN  SPTS.  NITRE  AND  BICARB.  POTASSA. 
frozen  so  that  boys  skated  upon  it.  The  idea  of  applying  the 
machine  to  the  reduction  of  the  temperature  of  large  rooms  for 
brewers  and  others  who  need  a  moderate  heat  in  their  processes, 
is  at  present  being  studied  practically.  We  understand  a  ma- 
chine like  the  one  described  is  worth  $12,000,  and  when  worked 
constantly  will  make  about  one  thousand  tons  of  ice  per  annum. 
Machines  of  ten  tons  per  twenty-fours  hours  capacity  are  now  at 
work  in  New  Orleans,  the  price  of  which  are  $25,000. 
PhUadelplda,  Feb.  10,  1870. 
ON  THE  REACTION  BETWEEN  SPIRIT  OF  NITROUS  ETHER 
AND  BICARBONATE  OF  POTASSA. 
By  C.  J.  Rademaker,  M.  D. 
Always  preparing  sweet  spirits  of  nitre  according  to  the  pro- 
cess of  the  U.  S.  P.  and  keeping  it  standing  on  crystals  of  bi- 
carbonate of  potash,  as  first  suggested  by  Mr.  Harvey,  of  Leeds, 
I  invariably  observed  a  molecular  change  taking  place  in  the 
crystals  of  bicarbonate  of  potash,  without  any  perceptible  solu- 
tion taking  place.  The  irregular  eight-sided  prisms  of  bicar- 
bonate of  potash  gradually  elongated  themselves  into  needles 
about  one  inch  in  length.  In  order  to  find  the  cause  of  the 
molecular  change,  part  of  the  crystals  were  collected  on  a  filter, 
and  washed  with  distilled  water  until  all  taste  of  nitrous  ether 
was  removed.  The  crystals  were  transferred  to  a  beaker,  and 
treated  with  concentrated  sulphuric  acid  ;  which  was  attended 
with  an  evolution  of  a  large  quantity  of  gas,  which  became  red 
fumes  of  hyponitric  acid  as  they  ascended. 
From  the  above  it  will  be  seen  that  spirits  of  nitre  will  de- 
compose bicarbonate  of  potash,  with  the  formation  of  nitrite  of 
potash,  carbonic  acid,  and  ether,  without  any  perceptible  solution 
taking  place. 
The  ether  with  which  the  experiment  was  performed  was  per- 
fectly neutral,  as  it  had  been  distilled  from  bicarbonate  of  potash 
two  and  three  times  ;  for  that  reason  no  acidity  could  have  been 
the  cause  of  the  decomposition.  A  solution  of  bicarbonate  of 
potash  added  to  one  of  spirits  of  nitre  there  is  a  ready  decompo- 
sition, with  the  evolution  of  carbonic  acid,  formation  of  nitrite 
of  potash  and  ether.   Nitre,  as  prepared  by  some  of  our  chemists 
