^""ApdriSr""' }  Specimens  of  Spirit  of  Nitre.  189 
serious  if  the  bulk  of  the  nitric  oxide  be  not  previously  removed,  as  is 
done  in  the  nitrometer.  Thus,  if  an  attempt  be  made  to  determine 
ethyl  nitrite  by  adding  the  sample  of  spirit  to  an  acidulated  solution 
ot  potassium  iodide  contained  in  an  open  basin,  and  immediately 
titrating  with  standard  thiosulphate,  the  first  result  is  too  low,  owdng 
to  the  nitrous  ether  requiring  a  sensible  time  for  its  decomposition.  In 
a  few  minutes  this  error  is  more  than  compensated  by  the  additional 
amount  of  iodine  set  free  by  the  nitrous  acid  produced  by  the  action 
of  the  air  on  the  nitric  oxide  formed  in  the  primary  reaction,  and  this 
liberation  of  iodine  goes  on  so  rapidly  that  the  stirring  necessary  to 
mix  the  standard  solution  with  the  liquid  in  the  basin  causes  the  solu- 
tion again  to  acquire  a  yellow  tinge,  which  rapidly  deepens.  If  the 
liquid  in  the  basin  be  allowed  to  stand  for  some  time  exposed  to  the 
air  before  titrating,  as  is  recommended  by  Dott,  the  iodine  set  free 
often  amounts  to  fully  twice  the  quantity  primarily  liberated  by 
reaction  with  the  ethyl  nitrite  present. 
I  have  to  thank  Messrs.  Dott,  Dymond,  Leech,  MacEwan,  Rim- 
mington,  Williams  and  others  for  information  and  samples  connected 
with  my  experiments,  and  Mr.  J.  H.  Worrall  for  assistance  in  the 
manipulations. — Phar.  Jour,  and  Trans.,  Feb.  21,  1885,  p.  673. 
EXAMINATION  OF  SOME  OLD  SPECIMENS  OF  SWEET 
SPIRIT  OF  NITRE.i 
By  Peter  MacEwan. 
At  an  Evening  Meeting  of  the  North  British  Branch  of  the  Phar- 
maceutical Society,  held  January  14,  1858,  Mr.  Jacob  Bell,  then 
President  of  the  Society,  in  the  chair,  a  paper  on  '^Methylated  Spirit" 
was  communicated  by  Mr.  J.  F.  MacFarlan.^    This  paper  embodied 
'^a  report  on  the  manufacture  of  sweet  spirit  of  nitre  from  methylated 
spirit  by  Mr.  Phillips.''    Mr.  Phillips  was  instructed  by  the  Govern- 
ment to  draw  up  this  report,  because  a  paper  which  Mr.  MacFarlan 
had  communicated  to  the  Pharmaceutical  Society  seemed  to  indicate 
that  if  methylated  spirit  were  converted  into  sweet  spirit  of  nitre,  me- 
thyl alcohol  was  got  rid  of.    Mr.  MacFarlan  did  not  really  mean  this, 
but  such  was  the  construction  placed  upon  what  he  said. 
^  Read  at  a  meeting  of  the  Edinburgh  Chemists'  Assistants  and  Appren- 
tices' Association,  January  25. 
"  Pharm.  Journ.,"  xvii,  412. 
