370 
NOTES  ON  IODIDE  OF  POTASSIUM,  ETC. 
less  cost  than  the  English  manufacturer,  arising  principally  from 
the  great  value  of  chloride  of  potassium  in  France,  the  chloride 
being  a  secondary  product  in  the  manufacture  of  'iodine.  Re- 
cently, however,  the  Emperor  of  the  French  has  taken  the  duty 
off  chloride  of  potassium,  and  this,  together  with  the  late  disco- 
very of  an  island,  the  superstratum  of  which  is  entirely  com- 
posed of  almost  pure  chloride  of  potassium,  while  the  strata  below 
consist  of  chloride  of  sodium,  etc.,  will  seriously  affect  the  value 
of  the  chloride  of  potassium  produced  in  the  manufacture  of 
iodine.  Under  these  circumstances  it  is  generally  believed  that 
this  important  branch  of  industry  will  be  to  some  extent  trans- 
ferred to  this  country.  Iodine  for  many  years  past  has  been  a 
favorite  article  with  wealthy  speculators  for  the  investment  of 
large  capital,  and  it  has  ranged  from  3jc?.  to  2s.  8d.  per  ounce 
in  a  few  months.  About  two  years  since  it  fell  to  3J<#.  per 
ounce,  which  was  supposed  to  be  owing  to  the  ingenious  and  eco- 
nomical process  of  Mr.  Stanford.  By  the  old  process  one  ton  of 
seaweed  would  only  yield  from  eight  to  fourteen  pounds  of 
iodine. 
Formerly  commercial  iodine  contained  a  large  percentage  of 
moisture,  and  on  keeping  the  iodine  for  twelve  months  this  loss 
sometimes  amounted  to  10  lb.  in  a  cwt.,  a  great  deal  of  which 
was  absorbed  by  the  staves  of  the  casks  or  passed  through  them 
and  was  lost.    The  moisture  is  generally  estimated  by  pressing 
the  iodine  between  folds  of  blotting-paper,  and  the  appearance 
of  the  paper  indicates  the  amount  of  moisture  present.  Iodine 
sometimes  contains  iodide  of  cyanogen,  which  rises  in  fine  white 
needles  when  the  iodine  is  heated.    This  is  an  accidental  impu- 
rity produced  by  one  of  the  processes  sometimes  adopted  in  the 
manufacture.    Iodine  has  been  adulterated  to  some  extent  with 
manganese,  alumina,  sand,  etc.,  although  this  is  not  of  frequent 
occurrence.    A  quantity  of  iodine  purchased  some  weeks  since 
was  found,  on  examination,  to  contain  in  each  keg  of  100  lb.  2  lb. 
of  a  substance  or  adulteration  which  was  proved  to  be  furnace 
drift,  or  the  substance  found  in  the  flues  of  steam-boilers.  This 
claim  was  not  allowed  by  the  seller,  owing  to  the  iodine  having 
been  approved  on  inspection  without  testing.    This  may  be  of 
some  value. to  buyers  of  iodine.    The  facility  and  perfection  by 
