544 
New  Method  of  Treating  Seaweeds. 
Am  Joiir.  Pharm. 
Nov.,  1885. 
NEW  METHOD  OF  TREATING  SEA-WEED, 
{Condensed  from  the  Report  on  the  Chemical  Industries  at  the  International 
Inventions  Exhibition,  London,  1885,  by  Prof.  Samuel  P,  Sadiler.) 
The  exhibit  of  Mr.  E.  C.  C.  Stanford  illustrates  generally  the  man- 
ufacture of  iodine,  bromine  and  potassium  salts  from  sea- weed,  besides 
that  of  the  new  and  interesting  substance,  Algin,  first  isolated  and 
studied  by  Mr.  Stanford ;  also  many  of  the  metallic  alginates.  It 
would  appear  that  amongst  sea-weeds,  the  algse  possess  the  power  of 
assimilating  the  iodine  from  sea-water  to  about  ten  times  the  extent  of 
the  bromine,  and  that  amongst  the  algse  the  Laminaria  and  the  Fuci 
are  the  kelp-producing  species  of  the  order  referred  to.  The  drift- 
kelp  is  made  from  two  varieties  of  red  wjeds,  or  Laminaria,  the  L, 
digitata  and  the  L.  stenophylla.  The  former  is  known  as  tangle,  and 
both  kinds  are  always  submerged.  These  sea-weeds,  and  especially 
the  latter,  are  much  injured  by  rain,  and  are  often  after  drying  almost 
valueless.  If  well  preserved,  the  Laminari^e  contain  ten  times  as 
much  iodine  as  the  Fuci.  It  furnishes  the  only  kelp  now  used  for 
making  iodine.  The  usual  yield  of  kelp  from  100  tons  of  wet  sea- 
weed is  5  tons,  and,  as  only  half  of  this  is  soluble,  two  and  one-half 
tons  form  the  total  valuable  product  of  what  may  be  called  the  native 
process,  and  this  must  pay  for  the  labor  of  cutting,  carrying,  drying 
and  burning  100  tons  of  wet  sea-weed.  As  the  people  in  burning  the 
weed  use  such  a  heat  as  to  produce  a  sort  of  slaggy  mass,  and  lose 
thereby  about  half  the  iodine,  Mr.  Stanford  proposed  the  so-called 
char-process,  by  which  all  the  iodine  is  saved.  The  weed  in  this  pro- 
cess is  submitted  to  destructive  distillation  in  iron  retorts,  leaving 
behind  a  loose  porous  charcoal,  retaining  the  salts  and  the  iodine,  and 
yielding  in  the  distillate  ammonia,  acetic  acid  and  tar.  In  a  still 
newer  process — in  fact,  the  one  referred  to  in  the  title  of  the  exhibit 
— Mr.  Stanford  extracts  first  the  potassium  chloride  ("muriates^'), 
potassium  sulphate  and  "  kelp-salt (sodium  chloride  containing  some^ 
carbonate  and  including  the  iodides),  by  simple  maceration  in  cold 
water.  The  amount  so  removed  from  the  air-dried  Laminaria  is  about 
one-third  of  its  weight  (thirty- three  per  cent.),  of  which  twenty  to 
twenty-two  per  cent,  are  mineral  salts,  and  the  balance  consists  of  dex- 
trin, mannite  and  extractive  matter,  leaving  two-thirds  of  the  plant 
(sixty-six  per  cent.)  for  further  treatment  apparently  unaltered.  This 
residue  contains  the  peculiar  new  substance,  Algin,  and  the  cellulose. 
