36  Preparation  of  Amyl  Nitrite,         {Am  ja0nu!*i£6.arm- 
the  first  experiment.  The  tendency  of  the  amyl  alcohol  to  heat  up 
was  much  less  marked.    The  washed  product  distilled  gave — 
73  per  cent,  under  100°  C. 
84      "         "   105°  C. 
88  "         "   110°  C. 
This  result  was  much  better  than  the  first  one,  but  cannot  be  con- 
sidered altogether  satisfactory. 
Experiment  No.  3. — Nitric  acid  of  sp.  gr.  1350  was  now  employed; 
the  quantity  of  gas  absorbed  was  considerable,  but  much  more  unab- 
sorbable  gas  was  produced  than  in  the  previous  experiments.  The 
tendency  for  the  amyl  alcohol  to  heat  up  was  very  much  diminished. 
The  product  distilled  gave — 
89  per  cent,  under  100°  C. 
95      "         "   105°  C. 
This  was  considered  very  satisfactory. 
Experiment  No.  4. — We  now  employed  acid  of  sp.  gr.  1300;  this 
is  the  strength  of  acid  recommended  by  Liebig,  and  since  by  Stenhouse 
and  Groves  in  a  paper  read  before  the  Chemical  Society  in  1877.  In 
this  case  it  was  found  that  most  of  the  gas  given  off  was  incapable  of 
absorption  by  the  amyl  alcohol ;  still  a  small  percentage  was  absorbed, 
and  after  passing  a  very  considerable  amount  of  the  gas  through  the 
alcohol  the  reaction  was  effected,  and  the  product,  washed  and  dis- 
tilled, gave — 
93  per  cent,  under  lj)0o  C. 
95      "         "   105°  C. 
This  result  was  very  good,  but  wasteful  on  account  of  the  large 
quantity  of  gas  which  had  to  be  employed. 
Experiment  No.  5. — In  this  experiment  we  varied  our  process  some- 
what, and  employed  a  mixture  of  gases,  with  very  satisfactory  results. 
In  a  glass  vessel  fitted  with  exit  tube  and  stoppered  acid  funnel,  a 
quantity  of  pure  nitrite  of  sodium  together  With  a  little  water  was 
placed,  and  to  the  mixture  nitric  acid  was  allowed  to  flow  slowly  in. 
The  resulting  gas  was  not  as  might  have  been  expected  nitrous  acid 
(N2Os),  but  was  clearly  nitrogen  peroxide  (N02).  It  was  colorless 
until  allowed  to  come  in  contact  with  the  air,  when  it  gave  dense  red 
fumes,  and  was  not  to  any  appreciable  extent  absorbed  by  amyl  alcohoL 
The  gas  thus  produced  was  passed  into  the  upper  part  of  a  vessel  con- 
taining arsenious  acid  and  nitric  acid  sp.  gr.  1500,  and  giving  off  the 
red  gas,  as  mentioned  in  our  experiment  No.  1.    The  two  gases  were 
