Am.  Jour.  Pharm.  ) 
Sept  ,  1880.  / 
Fucus  Vesiculosus, 
435 
Quantitative  Examination. — Amount  of  water,  2*26,  calculated  from 
10  grams. 
Amount  of  ash,  calculated  for  the  dried  plant,  1*59. 
Amount  of  ash  soluble  in  water,  '924. 
Amount  of  ash  soluble  in  hydrochloric  acid,  '675. 
The  watery  solution  of  the  ash  was  made  up  to  30  cc. 
To  10  cc.  of  the  solution  a  solution  of  i  part  ferrous  sulphate  and 
2  parts  sulphate  of  copper  was  added  \  a  dirty  white  precipitate  of 
cuprous  iodide  (CU2I2)  was  formed  ;  when  washed  and  dried  it  weighed 
•109  gram,  showing  =  '072  iodine. 
To  the  solution,  after  removal  of  the  iodide,  a  solution  of  nitrate  of 
silver  was  added,  which  gave  a  white  precipitate  of  bromide  and  chlo- 
ride of  silver.  When  washed,  dried  and  fused  it  weighed  '427  gram. 
The  double  salt  was  then  transferred  to  a  light  weighed  bulb  tube,  and 
fused  in  the  bulb.  The  mass  was  allowed  to  cool  and  then  weighed. 
Through  this  a  slow  stream  of  dry,  pure  chlorine  gas  was  conducted, 
and  heat  was  then  applied  to  the  contents  of  the  bulb  to  fusion,  and 
the  contents  occasionally  made  to  roll  about  by  revolviug  the  bulb. 
After  about  25  minutes  the  tube  was  taken  off  and  allowed  to  cool. 
The  tube  was  then  held  in  an  oblique  position,  that  the  chlorine  gas 
might  pass  out  and  be  replaced  by  atmospheric  air,  and  then  weighed. 
The  tube  was  heated  again  in  the  same  way  and  the  process  repeated 
until  the  two  last  weighings  were  the  same.  The  fused  mass,  after 
treatment  with  chlorine,  gave  '380  gram  of  pure  chloride  of  silver. 
The  difference  between  the  mixed  silver  bromide  and  chloride  and  the 
chloride  of  silver  was  found  to  be  -047  gram. 
The  difference  between  the  molecular  weight  of  — ? — -  and 
188  143-5 
=  44*5,  thus  giving  '198  silver  bromide,  '084  bromine,  '227  silver 
chloride,  =  0*56  chlorine. 
Separation  of  Potash  and  Soda. — In  this  separation  the  two  salts  must 
exist  as  chloride.  Therefore  the  bromide  and  iodide  were  converted 
by  evaporating  to  dryness  10  cc.  of  the  solution  of  the  ash  with  hydro- 
chloric acid  in  excess.  The  amount  of  double  chloride  of  potassa  and 
soda  determined  and  found  to  weigh  '209  gram.  This  was  dissolved 
in  a  little  water,  a  concentrated  neutral  solution  of  bichloride  of  plati- 
num added  in  excess,  and  evaporated,  in  a  porcelain  dish  nearly  to  dry- 
ness, at  a  very  low  heat.  Spirits  of  wine  was  then  added  to  the  resi- 
due. This  was  allowed  to  stand  for  four  hours.  The  undissolved 
.last  was  then  transferred  to  a  weighed  filter  and  washed  with  spirits  of 
