New  Method  of  Treating  Seaweeds.  545 
The  comparison  between  the  three  processes  is  of  considerable  interest, 
as  showing  the  advance  made  upon  the  old  kelp  process,  so  tenaciously 
adhered  to  and  persisted  in  by  the  natives  of  the  West  Coast,  by  Mr. 
Stanford's    char and    wet processes. 
Kelp  Process. 
Per  cent,  utilized,  18. 
-r^  ,     -    ,  f  Salts,  9  tons.      \       f  Eesiduals  :  kelp  waste,  18  \ 
i^elp,  lb  tons  <j  Iodine,  270  lbs.  j       \    tons.    Valueless.  / 
Char  Process. 
Per  cent,  utilized,  36. 
^,           ,  f  Salts,  15  tons.     ")       r  Residuals  :    charcoal,    36  \ 
l.nar,  6b  tons  ^  Iodine,  600  lbs.  /      \    tons,  tar  and  ammonia,  j 
Wet  Process. 
Per  cent,  utilized,  70. 
fSnlts  ^Otons     ]       f Residuals:  algin  20  tons. 
Water  extract,  33  tons,  j  ^^^^^^.j^g^"^^^^        j      j     cellulose  15  tons,  dex- 
In  this  new  process,  the  sea-weed  is  to  be  exported  and  worked  at  a 
central  factory,  and  all  the  common  varieties  can  be  used.  The  weed 
is  first  boiled  with  sodium  carbonate,  the  solution  is  filtered  and  pre- 
cipitated with  sulphuric  acid,  the  precipitate  being  the  new  substance, 
algin,  which  resembles  albumen,  and  contains  all  the  nitrogen,  and, 
moreover,  all  that  is  nutritious  in  the  sea- weed.  The  solution  is  now 
neutralized  with  limestone,  the  sulphate  of  lime  deposited,  the  neutral 
solution  evaporated  down,  and  the  sulphate  of  soda  crystallized  out. 
The  mother-liquor,  containing  all  the  potash  salts  and  iodine,  is  car- 
bonized, forming  the  ^'  kelp-substitute."  The  residue  on  the  filter  is 
the  cellulose.    The  whole  plant  is  thus  utilized.    (See  table.) 
Residue. 
Soda  Solution. 
Precipitated  by 
sulpliuric  acid. 
Retained  in  solution. 
CeUulose. 
Algiu. 
Sulphate  of  soda,  crystal-  Mother-liqnor, carbonized 
lizes  out  as  Glauber's  salt,    is  kelp-substitute. 
Algin  has  fourteen  times  the  viscosity  of  starch,  and  thirty-seven 
times  that  of  gum-arabic.  Algin  or  sodium  alginate  in  solution  is 
precipitated  or  coagulated  by  alcohol,  acetone  and  collodion,  but  not 
by  ether.  It  is  precipitated  by  mineral  acids,  various  salts,  and  by 
lime  and  baryta  water.    The  solution  is  not  precipitated  or  coagulated 
35 
