292 
SPIRITUS  ^ETHERIS  NITRICI. 
distilled  over.  This  is  redistilled  to  17  f.3.  The  first  product 
measures  8  f.  §  received  up  to  156°,  is  of  a  golden  yellow  color, 
and  has  a  s.  g.  of  -8914  at  50°.  The  second  product  17  f.3  is 
of  a  paler  yellow  and  has  a  density  of  -862  at  50°.  The  rejected 
portions  still  contain  some  ether,  probably  3  f«5  of  the  same 
density  as  the  last  product.  By  a  calculation  based  upon  the 
specific  gravities,  this  would  give  to  the  officinal  spirit  of  nitre 
by  this  process,  a  composition  of  123  f.,1  alcohol,  and  5  f.3  of 
pure  dry  hyponitrous  ether,  or  about  4  per  cent,  of  the  ether 
under  the  most  favorable  circumstances. 
The  sweet  spirit  of  nitre  obtained  by  this  process  is  a  volatile, 
transparent,  bright  liquid,  of  a  greenish  yellow  tint — never  color- 
less, and  of  a  fragrant  but  not  pungent  odor.  It  boils  at  156° 
to  158°  and  has  a  specific  gravity  of  -840  to  -841  at  609  when 
freshly  made.  It  is  perfectly  neutral  to  test  paper,  and  gives  a 
deep  straw  color  with  dilute  solution  of  potassa  within  half  an 
hour. 
With  good  materials  and  careful  manipulation  this  process 
yields  an  excellent  medicinal  preparation  liable  only  to  the  objec- 
tions that  it  contains  too  much  aldehyd,  and  is  not  as  uniform 
in  strength,  nor  quite  as  strong  as  desirable.  When  put  up  at 
once  in  half  pint  bottles,  well  filled  and  well  stopped  with  waxed 
glass  stoppers,  and  the  bottles  covered  with  dark  paper,  it  keeps 
well.  Several  bottles  of  it  made  in  March,  1854,  were  examined 
recently  in  connection  with  this  part  of  the  subject,  and  were 
found  to  have  undergone  no  perceptible  change.  It  is  the  prac- 
tice of  this  laboratory  to  make  this  preparation  fresh  for  every 
vessel  of  large  class  that  is  fitted  out  in  the  navy,  and  the  pre- 
paration now  examined  was  made  for  the  frigate  Columbia,  then 
fitted  out  as  the  flag  ship  of  the  home  squadron,  and  was  returned 
with  the  stores  of  that  vessel  when  she  was  laid  up,  after  a 
cruise  of  nearly  two  years,  principally  in  the  West  Indies.  As 
a  test  of  the  keeping  properties  of  the  preparation  when  well 
made,  I  regard  this  as  conclusive.  Another  specimen  one  year 
and  three  months  old,  is  in  the  same  good  condition. 
After  having  practiced  this  process  bi-monthly  or  oftener  for 
two  years,  it  was  abandoned  in  search  of  a  better  and  more  con- 
venient one,  for  the  following  reasons  : — 
It  is  unnecessarily  circuitous  and  complex. 
