^""Atrir'isS^™'}  Determination  of  Ethyl  Nitrite.  187 
No.  1  sample  was  prepared  by  Mr.  J.  Williams  by  dissolving  one 
part  by  weight  of  carefully  purified  ethyl  nitrite  in  three  parts  by 
weight  of  absolute  alcohol.  The  density  was  'SSST.  With  corrections 
for  solubility,  pressure  and  temperature,  the  ethyl  nitrite  shown  by  the 
process  in  this  specimen  came  to  nearly  24  per  cent.  As  the  sample  at 
the  time  of  examination  had  a  sensibly  acid  reaction,  indicating  slight 
decomposition,  I  believe  the  corrected  result  to  express  with  consider- 
able accuracy  the  actual  composition  of  the  sample.  Another  solution 
of  ethyl  nitrite  in  absolute  alcohol  which  I  have  had  for  upwards  of 
seven  years,  still  contains  a  notable  quantity  of  nitrous  ether. 
No.  2  sample  was  the  ordinary  commercial  B.  P.  article,  prepared 
by  Messrs.  Rimmington  and  Son,  of  Bradford.  It  gave  1  per  cent, 
of  ethereal  layer  by  the  chloride  of  calcium  test. 
Nos.  5  and  6  w^ere  analyzed  immediately  on  opening  the  bottles,  as 
freshly  sent  out  by  the  wholesale  house,  which  is  one  of  the  first  repu- 
tation. I  have  analyzed  them  again,  after  an  interval  of  a  month? 
and  find  that  5cc.  yielded  respectively  14*4  and  22'3cc.  of  nitric  oxide, 
measured  at  the  ordinary  temperature  of  the  laboratory.  Hence  they 
were  practically  unchanged,  though  kept  in  a  warm  room. 
I  have  also  employed  tlie  process  for  the  assay  of  a  considerable 
number  of  other  commercial  samples,  and  it  has  given  me  every  satis- 
faction.* 
The  nitrometers  commonly  sold  are  furnished  With  three-way-taps, 
but  for  the  purpose  in  question  this  is  unnecessary,  an  ordinary  tap 
being  sufficient.  A  nitrometer- tube,  which  I  have  had  made  for  me, 
holds  50  cc.  The  cup  is  narrow  and  cylindrical,  and  has  marks  at 
5  and  10  cc.  above  the  tap.  This  arrangement  renders  the  use  of  a 
pipette  or  other  separate  measuring  arrangement*  unnecessary,  as  the 
cup  can  be  filled  to  the  5  cc.  mark  wdth  the  sample,  and  thus  a  definite 
amount  taken  for  the  analysis.^ 
With  the  aid  of  such  a  nitrometer,  the  assay  of  spirit  of  nitrous 
ether  for  ethyl  nitrite  and  other  nitrous  compounds  is  reduced  to  an 
operation  of  the  utmost  simplicity,  and  literally  does  not  require  more 
than  ten  minutes  for  its  completion,  including  the  necessary  calculation. 
The  results  are  as  constant  as  can  be  desired,  and  the  process  as  near 
an  approach  to  accuracy  as  is  required  for  ordinary  purposes.  I  believe 
^  Messrs.  Ciibley  and  Preston,  of  High  Street,  Sheffield,  are  now  prepared 
to  supply  these  nitrometers  to  those  desirous  of  employing  the  process  men- 
tioned in  the  text. 
