PRODUCTION  OF  IODINE  AND  BROMINE. 
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THE  PRODUCTION  OF  IODINE  AND  BROMINE. 
By  W.  H.  Chandler. 
To  Scheele  is  the  world  indebted  for  the  first  intimation  of 
the  elementary  existence  of  fluorine  and  chlorine,  he  having  in 
1771  referred  the  action  of  sulphuric  acid  upon  fluor-spar  to  the 
freeing  of  a  distinct  acid  from  the  mineral,  though  whether  fluo- 
rine has,  even  up  to  the  present  day,  been  isolated,  is  a  matter 
of  great  doubt.  In  1774  the  same  chemist  isolated  chlorine. 
In  1811  Courtois  separated  iodine  from  the  waste  liquor  from 
the  manufacture  of  soda  ash  from  sea-weed,  followed  by  the  dis- 
covery of  bromine  in  the  bittern  of  sea-water  by  Balard  in  1826. 
The  isolation  of  these  four  closely-allied  elements  from  their 
compounds  is  thus  included  in  a  century,  and  the  application  of 
them  to  economical  purposes,  to  any  extent,  was  accomplished 
since  the  beginning  of  the  present  century.  Their  close  relation- 
ship, their  physical  properties,  and  their  chemical  affinities, 
which  are  nearly  in  an  inverse  proportion  to  their  chemical  equi- 
valents, induce  one  to  the  supposition  that  they  are  modifications 
of  the  same  element. 
The  isolation  of  chlorine,  bromine,  and  iodine  from  their  com- 
pounds with  the  alkalies,  is  accomplished  Avith  equal  facility.  But 
the  abundant  store  of  the  former  in  the  enormous  deposits  of  salt 
throughout  the  world  and  in  solution  in  the  ocean  and  inland 
seas,  forms  a  striking  contrast  to  the  rarity  of  the  two  latter 
halogens.  In  combination  with  silver,  bromine  and  iodine  are 
found  in  some  rare  ores  in  Mexico  and  South  America.  Chatin 
claims  to  have  detected  iodine  in  rain-water,  though  in  very 
minute  quantities,  and  even  in  the  atmosphere.  In  sea-water 
traces  of  it  have  been  uniformly  detected,  though  not  in  quanti- 
ties sufficient  for  quantitative  estimation.  Bromine  exists  in 
slightly  larger  quantities,  and,  associated  Avith  iodine  and  chlo- 
rine, is  found  in  the  ocean  and  inland  seas,  the  various  mineral 
and  saline  springs,  and  salt  deposits  throughout  the  world. 
According  to  Von  Bibra,  the  amount  of  bromine  in  the  Atlan- 
tic O.cean,  in  one  United  States  gallon,  is  24  grns.  ;  in  the  Dead 
Sea,  examined  by  Ilerapath,  121*5  grns. ;  in  the  dried  residue  of 
the  Mediterranean,  1*15  per  cent. ;  in  the  mineral  spring  of 
