PREPARATION  OF  SPIRIT  OF  NITROUS  ETHER. 
321 
ON  THE  PREPARATION  OF  SPIRIT  OF  NITROUS  ETHER. 
By  Theopiiilus  Redwood,  Ph.D., 
(Professor  of  Chemistry  arid  Pharmacy  to  the  Pharmaceutical  Society.) 
An  impure  spirituous  solution  of  nitrous  ether  has  been  long  and 
extensively  used  in  medicine,  under  the  several  names  of  Dulcified 
Acid  of  Nitre,  Sweet  Spirit  of  Nitre,  Spirit  of  Nitric  Ether,  and 
Spirit  of  Nitrous  Etlier.  It  appears  to  have  been  first  vaguely 
described  as  far  back  as  the  thirteenth  century,  by  Raymond 
Lully,  but  it  was  more  prominently  brought  into  notice  by  the 
great  champion  of  chemical  medicines,  Basil  Valentine,  about 
two  hundred  years  later.  The  process  generally  adopted  for  its 
preparation  has  consisted  in  distilling  a  mixture  of  nitric  acid 
and  spirit ;  but  several  modifications  of  the  process  have  from 
time  to  time  been  made,  the  proportion  of  acid  in  relation  to  the 
spirit  having  been  frequently  varied,  and  other  alterations  effec- 
ted, with  the  view  of  meeting  difficulties  that  have  presented 
themselves,  or  of  obviating  objections  that  have  been  found  to 
apply  to  the  products  obtained. 
In  1746  this  preparation  was  first  introduced  in  the  London 
Pharmacopoeia  under  the  name  of  Spiritus  nitri  duhis,  which 
was  changed  in  1788  to  Spiritus  cetheris  nitrosi,  and  again  in 
1809  to  Spiritus  cetheris  nitrici. 
The  process  given  in  the  London  Pharmacopoeia  of  1746  con- 
sisted in  submitting  to  distillation  a  mixture  of  six  troyounces 
of  strong  nitric  acid,  of  about  1-5  specific  gravity,  with  thirty- 
two  fluid-ounces  of  rectified  spirit.  This  process  remained  un- 
altered until  1809,  when  the  proportion  of  nitric  acid  was  re- 
duced to  one-half.  In  1824  a  slight  change  was  made  in  the 
quantity  of  spirit  directed  to  be  distilled  from  the  mixture,  which 
was  equivalent  to  reducing  the  proportion  of  acid.  The  next 
change  was  made  in  1851,  when  the  proportion  of  acid  was  still 
further  diminished,  and  a  weaker  acid,  of  specific  gravity  1-42, 
was  directed  to  be  used.  The  process  now  consisted  in  mixing 
3J  fluid-ounces  of  nitric  acid  (sp.  gr.  1-42)  with  2  pints  (40  fluid- 
ounces)  of  rectified  spirit,  and  distilling  28  fluid-ounces  of  pro- 
duct from  the  mixture. 
It  will  thus  be  seen  that  the  changes  which  have  been  made 
21 
