PREPARATION  OP  SPIRIT  OF  NITROUS  ETHER.  325 
I 
and  glyoxalic  acids.  Hydrocyanic  acid  is  also  said  to  have  been 
produced  in  some  instances.  I  do  not  propose  to  enter,  on  the 
present  occasion,  into  this  part  of  the  subject,  beyond  alluding 
to  the  fact,  that,  as  these  bodies  are  produced,  there  must  be  loss 
of  alcohol  and  nitric  acid,  and  there  may  be  a  material  alteration 
effected  in  the  composition  of  the  distilled  product.  Intense 
action  is  therefore  to  be  avoided,  both  on  the  ground  of  economy, 
and  also  with  a  view  to  the  quality  of  the  product. 
I  believe  that  the  sweet  spirit  of  nitre  of  commerce  is  always 
obtained  by  the  distillation  of  a  mixture  of  nitric  acid  and  spirit, 
but  manufacturers  no  doubt  vary  their  methods  of  operating 
according  to  their  knowledge  and  experience.  The  objects  they 
have  especially  in  view  are,  the  means  of  satisfying  the  require- 
ments of  their  customers,  and  of  competing  with  each  other  in 
regard  to  quality  and  price.  The  article  is  manufactured  upon 
so  large  a  scale,  and  its  market  value  is  defined  within  such 
narrow  limits,  that  any  proposed  alteration  in  the  long  estab- 
lished process  for  its  production,  that  would  materially  alter  its 
character  or  enhance  its  price,  would  be  very  unlikely  to  be  gen- 
erally adopted. 
It  is  not  in  the  dispensing  of  medical  prescriptions  that  the 
great  bulk  of  the  sweet  spirit  of  nitre  of  commerce  is  used,  but 
as  a  popular  remedy  which  the  public  are  accustomed  to  prescribe 
on  their  own  responsibility.  As  originally  prepared,  and  as  met 
with  in  commerce,  it  is  an  impure  solution  of  nitrous  ether  in 
strong  spirit.  All  the  samples  that  I  have  ever  examined,  con- 
taining any  appreciable  quantity  of  nitrous  ether,  have  also  con- 
tained aldehyd,  and  I  therefore  consider  commercial  sweet  spirit 
of  nitre  to  be  essentially  a  solution  of  nitrous  ether  and  aldehyd. 
All  the  attempts  that  have  hitherto  been  made  to  exclude  alde- 
hyd have  practically  proved  failures,  either  by  excluding  at  the 
same  time  the  nitrous  ether,  or  by  unduly  increasing  the  cost  of 
the  process,  or  by  too  greatly  altering  the  character  of  the  pro- 
duct. The  London  process  failed  from  the  first  of  these  causes. 
The  Edinburgh  and  Dublin  processes  have  also  equally  failed 
from  the  latter  causes,  for  as  these  processes  consisted  in  the 
production  of  pure  nitrous  ether  as  a  preliminary  operation,  by 
a  somewhat  wasteful  method  more  applicable  to  operations  on  the 
