322 
PREPARATION  OF  SPIRIT  OP  NITROUS  ETHER. 
in  the  process  of  the  London  Pharmacopoeia  have  all  been  in  one 
direction,  and  have  consisted  in  a  succession  of  reductions  in  the 
proportion  of  nitric  acid  employed.  The  object  appears  to  have 
been  to  avoid  the  violent  reaction  which  occurs  when  strong  nitric 
acid  and  rectified  spirit,  in  certain  proportions,  are  submitted  to 
distillation.  When  nitric  acid  of  specific  gravity  1-42  is  em- 
ployed, little  or  no  chemical  action  occurs  unless  the  proportion 
of  acid  to  spirit  be  at  least  one  to  four  by  volume.  If  the  pro- 
portion be  one  to  three,  the  action  is  violent  and  uncontrollable  ; 
in  fact,  in  operating  on  more  than  small  quantities  of  material, 
the  process  under  these  circumstances  is  not  unattended  with 
danger.  As  the  chemical  action  becomes  more  intense  it  assumes 
a  more  complex  character,  large  quantities  of  uncondensable 
vapors  are  given  off,  and  much  waste  of  spirit  and  of  acid  neces- 
sarily ensues. 
The  following  experiments  were  made  to  determine  the  limits 
in  the  ratio  of  acid  and  spirit,  within  which  mixtures  of  nitric 
acid  (sp.  gr.  1-42)  and  rectified  spirit,  when  submitted  to  distil- 
lation in  the  usual  way,  yield  nitrous  ether  suitable  for  use  in 
medicine : — 
1.  A  mixture  of  one  fluid-ounce  of  nitric  acid  and  three  fluid- 
ounces  of  spirit  was  put  into  a  retort,  furnished  with  a  ther- 
mometer, and  lo  which  an  efficient  condenser  was  attached.  The 
heat  of  a  lamp  rfas  applied  until  the  temperature  rose  to  185°, 
when,  chemical  action  having  commenced,  the  lamp  was  extin- 
guished and  the  process  allowed  to  proceed  spontaneously.  The 
temperature  of  the  liquid  quickly  rose  to  205°  ;  a  violent  reac- 
tion occurred,  and  much  of  the  vapor  which  passed  over  escaped 
in  the  uncondensed  state.  After  a  short  time  the  temperature 
fell  to  175°,  but  again  rose  spontaneously  to  190°.  When  the 
action  finally  subsided,  there  were  two  fluid-ounces  of  condensed 
liquid  in  the  receiver,  and  nine  fluid-drachms  of  a  strongly  acid 
liquor  left  in  the  retort. 
2.  A  mixture  of  one  fluid-ounce  of  nitric  acid  and  four  fluid-ounces 
of  spirit  was  submitted  to  distillation  with  an  arrangement  such 
as  was  adopted  in  the  previous  experiment.  A  little  pure  spirit 
came  over  in  the  early  part  of  the  experiment,  but  this  was  soon 
followed  by  the  production  of  ether,  which  commenced  when  the 
