I 
23  z  Chemical  Notes.  { Km^rt\!^rm 
iodine  is  exceedingly  objectionable.  This  metal  is  soluble  in  concen- 
trated potassium  iodate,  and  cannot  be  precipitated  by  sulphuretted 
hydrogen,  except  after  great  dilution.  If  not  removed,  lead  affects  not 
merely  the  color,  but  the  forms  of  the  cry  stals. 
No  demonstrable  trace  of  potassium  carbonate  is  admissible,  either 
for  medical  or  photographic  purposes.  Potassium  iodide,  therefore, 
should  be  unaffected  by  salts  of  barium.  The  perfect  absence  of  chlo- 
rine can  never  be  attained,  as  even  the  best  sample  of  iodine,  as  well 
as  of  pctassium  carbonate,  contains  traces  of  this  impurity. 
Chilian  iodine,  obtained  from  soda-saltpetre,  is  becoming  a  formidable 
rival  to  the  European  product,  which  cannot  be  offered  at  a  reduced 
figure,  as  the  manufacturers  have  lost  their  market  for  potassium  chlo- 
ride in  consequence  of  the  rivalry  of  the  Stassfurt  mines.  Chilian 
iodine  is  met  with  in  commerce  either  as  a  paste  or  as  copper  iodide. — 
Chemical  News,  March.21,  1879,  from  Chemische  Industrie. 
Although  much  study  has  been  given  to  the  action  of  chlorine  upon 
calcium-hydrate,  very  little  attention  has  been  paid  to  the  action  of 
chlorine  upon  barium  or  strontium  hydrate.  J.  Konigel-Weisberg  has 
studied  this  action  in  the  case  of  barium  hydrate,  and  gives  the  follow- 
ing as  his  results  : 
1.  Barium  hydrate,  Ba02H2,  does  not  absorb  chlorine.  This 
absorption  depends  upon  the  presence  of  an  excess  of  water ;  the  more 
water  the  more  chlorine  absorbed,  and  this  continues  until  all,  or  nearly 
all,  the  barium  oxide  contained  in  the  substance  is  saturated  with  chlo- 
rine, reckoning  two  atoms  of  chlorine  to  one  molecule  of  BaO. 
2.  By  the  action  of  chlorine  is  formed  most  probably  a  hypochlorite 
along  with  the  chloride,  but  the  barium  hypochlorite  decomposes  at 
once  into  a  chlorate  and  chloride,  so  that  in  the  product  finally  obtained 
very  small  amounts  only  of  hypochlorites  can  be  found,  while  almost 
the  ent>re  chlorine  percentage  is  present  in  the  form  of  chloride  and 
chlorate.  The  reaction  can  therefore  be  expressed  in  the  way  usual 
for  the  action  of  chlorine  upon  the  alkalies:  6BaO-|-  1 2Cl=5BaCl2-|- 
Ba(C103)2. — Berichte  der  Chem.  Gesells.,  xii,  p.  346. 
Following  upon  the  method  suggested  by  J.  W.  Briihl  (this  journal, 
p.  188,  1879)  for  the  purification  of  mercury,  we  have  another  by  Lothar 
Meyer,  which  he  claims  involves  less  loss  of  mercury.  It  is  to  allow 
the  impure  mercury  to  fall  in  a  fine  stream  into  a  tall  tube  containing  a 
moderately  dilute  solution  of  commercial  ferric  chloride.    The  lower 
