82 
Sj).  uEtheris  Mtrosi,  B,  P. 
f  Am.  Jour.  Pharm. 
\     Feb.  1, 1871. 
SP.  ..ETHERIS  NITROSI,  B.  P. 
By  Alfred  E.  Tanner. 
Read  at  a  Meeting  of  the  Liverpool  Chemists'  Association,  Nov.  27,  1870^ 
The  process  in  the  B.  P.  is  the  one  usually  known  as  Redwood's  ; 
it  consists  in  distilling  a  mixture  of  rectified  spirit,  nitric  and  sulphuric 
acids,  together  with  copper  wire,  at  a  certain  temperature,  in  a  glass 
retort,  furnished  with  a  thermometer  ;  and  in  operating  on  the  Phar- 
macopoeial  quantity,  15  fluid  ounces  are  ordered  to  be  drawn  over, 
and  this  distillate  is  to  be  mixed  with  40  fluid  ounces  of  rectified 
.  spirit,  or  a  sufficiency,  so  that  the  mixture  may  correspond  to  the 
tests  for  sp.  gr.  and  percentage  of  CjHgNOg,  this  latter  being  deter- 
mined by  means  of  a  saturated  solution  of  Ca  CI. 
Now  I  have  followed  this  process  for  the  preparation  of  spiritus 
setheris  nitrosi  ever  since  the  Pharmacopoeia  was  published,  but  have 
never  succeeded  in  collecting  the  amount  of  distillate  there  ordered  ; 
on  no  occasion  have  I  been  able  to  produce  more  than  about  11  fluid 
ounces,  excepting  by  the  addition  of  more  nitric  acid  than  the  Phar- 
macopoeia allows,  and^  then  the  product  has  been  too  rich  in  nitrous 
ether. 
I  have  usually  found  this  11  fluid  ounces  of  distillate  to  contain  50 
per  cent,  of  C2H5NO2 ;  that  is,  it  will  show  a  separation  of  42  per 
cent,  when  agitated  in  a  graduated  tube  with  double  its  volume  of 
saturated  solution  of  a  Ca  CI ;  this,  then,  appears  to  contain  the 
whole  amount  of  CgH^NOg  required,  viz.,  about  5J  fluid  ounces,  or 
36*6  per  cent,  of  the  quantity  ordered  by  the  Pharmacopoeia  to  be 
drawn  over,  and  on  mixing  this  with  four  times  its  volume  of  rectified 
spirit,  the  mixture  corresponds  exactly  with  the  spiritus  setheris  nitrosi 
of  the  Pharmacopoeia,  showing  10  per  cent,  of  CgH^NOg  by  the  CaCl 
test,  and  having  a  sp.  gr.  •846. 
I  should  mention  that  this  11  fluid  ounces  of  distillate  was  pro- 
duced within  the  limit  of  temperature  ordered,  viz.,  180°,  but  by 
increasing  the  heat  to  200°  there  was  no  difficulty  in  distilling  about 
4J  fluid  ounces  more,  but  that  appeared  to  consist  principally  of 
spirit ;  it  was  not  acid  when  first  distilled,  but  became  so  in  a  few  days. 
On  the  last  occasion  of  preparing  sp.  aether,  nitros.,  I  made  a  few 
notes  which  may,  perhaps,  be  interesting  to  some. 
The  quantities  operated  upon  were  those  mentioned  in  the  B.  P., 
