S02 
SPIMTUS  JETHERIS  NITRICI. 
objectionable  method  of  estimating  or  comparing  the  ethereal 
strength  is  probably  that  of  fractional  distillation.  One  pint  of 
officinal  sweet  spirit  of  nitre  distilled  from  fragments  of  glass,  by 
a  water  bath,  yields  a  yellow  distillate  of  one  fourth  of  its  bulk, 
whilst  the  temperature  in  the  boiling  liquid  is  below  180°,  and 
such  a  distillate  contains  nearly  all  the  hyponitrous  ether  of  the 
preparation.  This  distillate,  again  distilled  in  precisely  the  same 
way,  yields  1  f.§  of  distillate  below  176°.  This  last,  upon  the 
addition  of  an  equal  bulk  of  water,  added  in  a  stream,  and  with- 
out agitation,  yields  a  supernatant  ethereal  layer  of  2|  f.g.  The 
preparation  by  the  proposed  process  yields  about  3  f.g.  These 
results  are  based  upon  a  number  of  trials,  and  are  not  too  high, 
but  will  be  found  to  indicate  the  comparative  value  very  con- 
veniently. Dilute  solution  of  potassa,  say  equal  parts  of  officinal 
solution  and  distilled  water,  is  an  excellent  test  for  aldehyd  in  a 
spirit  that  is  free  from  acid,  or  nearly  so,  provided  time  be  given 
for  its  reaction  to  develope  the  color.  I  have  never  seen  a  speci- 
men of  good  spirit  of  nitre  that  would  not,  in  the  proportion  of 
equal  parts,  yield  a  decided  straw  yellow  tint  with  this  test 
within  twelve  hours.  A  yellow  tint  is  usually  perceptible  within 
fifteen  minutes,  and  the  color  thence  grows  deeper  for  twelve 
hours,  when  it  becomes  of  a  golden  or  brownish  yellow  of  a  deep 
hue.  Where  aldehyd  is  in  undue  proportion,  this  change  occurs 
sooner,  and  becomes  ultimately  of  a  brown  hue,  even  within  an 
hour  or  two.  The  changes  appear  to  take  place  more  quickly  in 
warm  weather,  and  in  a  bright  light. 
The  sulphuric  acid  test  is  less  convenient  and  less  to  be  relied 
upon  in  my  hands. 
In  order  to  ascertain  the  relative  strength  the  officinal  prepara- 
tion bears  to  the  commercial  article  as  supplied  to  apothecaries 
generally,  six  samples  of  sweet  spirit  of  nitre  were  purchased 
and  examined.  Five  of  these  samples  were  obtained  from  five 
of  the  largest  and  most  respectable  wholesale  drug  establish- 
ments in  New  York  city,  and  one  from  a  large  establishment  that 
is  considered  to  be  of  second  rate  as  to  character.  As  these 
houses  represent  the  commerce  in  medicines,  under  the  most  fa- 
vorable circumstances,  so  the  samples  obtained  'from  them  may 
be  considered  as  fairly  representing  the  merchantable  articles 
and  the  manufacturers  that  supply  the  demand.    The  six  samples 
