OXALATE  OF  AMMONIA  AND  PRUSSIAN  BLUE. 
363 
tile  below  a  red  heat,  both  in  the  elementary  state  and  in  com- 
bination (except  when  united  with  a  heavy  fixed  metal).  2. 
From  its  hydrochloric  solution  it  is  readily  precipitated  by  me- 
tallic zinc,  in  the  form  of  a  heavy  black  powder,  insoluble  in  the 
acid  liquid.  3.  Ammonia  added  very  gradually  until  in  slight 
excess  to  its  acid  solution  gives  no  precipitate  or  coloration  what- 
ever, neither  does  the  addition  of  carbonate  or  oxalate  of  am- 
monia to  this  alakline  solution.  4.  Dry  chlorine  passed  over 
it  at  a  dull  red  heat  unites  with  it,  forming  readily  volatile 
chloride,  soluble  in  water.  5.  Sulphuretted  hydrogen  passed 
through  its  hydrochloric  solution  precipitates  it  incompletely, 
unless  only  a  trace  of  free  acid  is  present  ;  but  in  an  alkaline 
solution  an  immediate  precipitation  of  a  heavy  black  powder 
takes  place.  6.  Fused  with  carbonate  of  soda  and  nitre,  it  be- 
comes soluble  in  water  ;  hydrochloric  acid  added  in  excess  to 
this  liquid  producing  a  solution  which  answers  to  the  above 
tests,  2,  3,  and  5.  The  smallest  trace  of  this  substance,  what- 
ever it  may  prove  to  be,  introduced  into  the  burner  of  the 
spectrum  apparatus  gives  rise  to  a  brilliant  green  line,  perfectly 
sharp  and  well  defined  upon  a  black  ground,  and  almost  rival- 
ling the  sodium  line  in  brilliancy.  It  is  not,  however,  very  last- 
ing, owing  to  its  volatility,  which  is  almost  as  great  as  selenium, 
a  portion  introduced  at  once  into  a  flame  merel}^  shows  the  line 
as  a  brilliant  flash,  remaining  only  a  fraction  of  a  second ;  but 
if  it  be  introduced  into  a  flame  gradually,  the  line  continues 
present  for  a  much  longer  time.  The  elements  amongst  which 
alone  it  must  occur,  if  not  really  new,  are  antimony,  arsenic, 
osmium,  selenium,  and  tellurium  ;  these  and  their  compounds 
have  been  rigidly  scrutinized  in  the  spectrum,  by  Mr.  Crookes, 
without  exhibiting  a  trace  of  the  green  line  characteristic  of  the 
substance  in  question. —  Chemist  and  Druggist,  May  15,  1861. 
EFFECT  OF  OXALATE  OF  AMMONIA  UPON  THE  PRECIPI- 
TATION OF  PRUSSIAN  BLUE. 
By  a.  Duncan,  Jr. 
On  repeating  the  experiment  of  Professor  Arnandon  on  the 
influence  of  oxalate  of  ammonia  in  modifying  the  action  of  prus- 
siate  of  potash  on  a  salt  of  peroxide  of  iron,  by  which  the  pre- 
