Am/u°nue!if9h8arm-}     Amy  I  Nitrite  and  Nitrons  Ether.  277 
The  new  method  alluded  to  at  the  beginning  of  this  paper  is  based 
on  a  reaction  between  nitrous  and  chloric  acid,  thus : 
,  3HN02  -f  HCIO3  =  3HNO3  +  HQ. 
This  reaction  has  long  been  known,  but  seems  not  to  have  been 
utilized  for  quantitative  purposes  until  recently.  An  abstract  in 
Ztsch.  f.  ang.  Chem.,  1898,  p.  307,  which  is  the  only  reference  to 
this  method  the  writer  has  been  able  to  find,  is  translated  as 
follows  : 
"Estimation  of  Nitrites. — B.  Griitzner  [Rev.  fals.,  1898,  21),  dis- 
solves o-i  to  0-2  gramme  of  the  nitrite  in  500  c.c.  of  water,  adds 
N 
0.5  gramme  of  potassium  chlorate  and  a  known  volume  of  — 
silver  nitrate,  strongly  acidulates  with  nitric  acid,  while  shaking, 
N 
and  titrates  after  a  few  minutes  the  excess  of  silver  with  —  sodium 
10 
chloride."  It  would  have  been  of  interest  to  see  the  original  article, 
to  learn  the  reasons  for  some  of  the  procedures  directed,  but  the 
conclusion  is  reached  that  the  method  is  intended  primarily  for 
alkali  nitrites,  as  it  is  utterly  inadequate  in  the  above  form  for  the 
estimation  of  ethyl  and  amyl  nitrite. 
For  metallic  nitrites,  from  which  nitric  oxide  is  set  free  imme- 
diately upon  addition  of  a  stronger  acid,  such  great  dilution  with 
water,  as  is  directed,  may  not  be  objectionable,  and  will  prevent  loss 
of  nitric  oxide  when  the  reaction  is  permitted  to  go  on  in  an  open 
vessel,  but  a  large  quantity  of  water  is  not  necessary  for  the  esti- 
mation of  sodium  and  potassium  nitrites  in  the  writer's  experience, 
when  a  well-stoppered  flask  is  used,  and  in  the  assay  of  ethereal 
nitrites  such  a  dilution  would  retard  the  reaction  to  such  an  extent 
as  to  make  the  method  impracticable.  With  a  bulk  of  50  c.c.  for 
0  2  gramme  of  ethyl  nitrite,  about  thirty  minutes  was  required  for 
a  complete  reaction,  and  ten  to  fifteen  minutes  for  a  bulk  of  25  c.c. 
Greater  dilutions  than  these  would  only  cause  an  unnecessary  loss 
of  time. 
The  addition  of  silver  nitrate  at  the  beginning,  as  directed  by 
Griitzner,  necessitates  keeping  the  solutions  in  a  dark  place  until 
they  are  ready  for  titration,  but  as  it  has  been  found  that  frequent 
shaking  is  required  to  facilitate  the  reaction,  exclusion  from  light  is 
rather  inconvenient.  For  this  reason  parallel  experiments  were  made 
