210 
Crab- Orchard  Salt. 
(  Am.  Jour.  Pharm. 
t     May  1, 1871. 
As  it  was  interesting  to  make  a  fuller  examination  of  the  Crab 
Orchard  salt  in  this  market,  and  especially  to  examine  it  for  the  rarer 
elements,  I  have  made  an  analysis  of  a  sample,  obtained  from  Messrs. 
Bullock  and  Crenshaw,  in  the  laboratory  of  Dr.  A.  Genth,  of  Phila- 
delphia, to  whom  I  feel  under  many  obligations  for  valuable  aid  and 
suggestions.  I  am  also  indebted  to  Dr.  Robert  Bridges,  who  kindly 
examined  the  separated  alkalies  with  a  spectroscope.  The  following 
are  the  methods  which  were  employed  : — 
One  gramme  of  the  salt  was  dried,  for  several  days,  over  sulphuric 
acid,  losing  6-030  per  cent,  of  moisture  ;  on  exposure  to  a  tempera- 
ture of  120°  C,  it  lost  an  additional  quantity  of  water,  viz.,  25*57 
per  cent.  ;  ignition,  at  a  dull  red  heat,  produced  a  loss  of  12-95  per 
cent  of  water  and  a  small  quantity  of  organic  matter,  the  total  loss 
by  drying  and  ignition  being  44*55  per  cent.    One  gramme  lost,  on 
ignition  at  a  dull  red  heat,  44*76  per  cent.     One  gramme  was  dis- 
solved in  water,  acidulated  with  chlorhydric  acid;  the  insoluble  resi- 
due being  filtered  off,  it  was  precipitated  with  chloride  of  barium,  for 
sulphuric  acid;  the  sulphate  of  barium,  washed  and  ignited,  weighed 
1*0304  grammes,  equal  to  35*379  per  cent,  of  sulphuric  acid.  One 
gramme,  treated  in  a  similar  way,  gave  35*578  p.  c.  of  sulphuric  acid. 
Ten  grammes  were  dissolved  in  water  slightly  acidulated  by  nitric  acid  ; 
the  insoluble  portion  being  filtered  oif,  the  solution  was  treated  with 
nitrate  of  silver  for  chlorine,  the  washed  chloride  of  silver  was  re- 
duced to  metallic  silver,  by  boiling  with  soda  and  a  small  quantity  of 
glucose  ;  this,  being  washed,  dried  and  ignited,  was  then  treated  with 
a  few  drops  of  acetic  acid,  and  again  washed,  to  remove  the  last 
traces  of  soda.    The  metallic  silver  weighed  0*0885  gramme,  equal 
to  0*291  per  cent,  of  chlorine.    Two  grammes  were  dissolved  in  hot 
water,  the  insoluble  residue,  being  washed,  dried,  ignited  and  weighed, 
gave  0*380  per  cent.    To  the  filtrate  from  the  insoluble  matter,  chlo- 
ride of  ammonium  was  added,  then  ammonia  and  oxalate  of  ammo- 
nia, by  which  the  lime  and  sesquioxide  of  iron  were  precipitated, 
which,  being  washed  and  ignited,  were  moistened  with  carbonate  of 
ammonia,  reheated,  to  expel  the  latter,  and  weighed,  the  weight  of 
the  mixture  being  *0216  gramme.   This  was  treated  with  dilute  nitric 
acid,  which  dissolved  the  carbonate  of  lime,  and  left  the  sesquioxide 
of  iron,  which,  after  ignition,  weighed  -0028  gramme  or  -14  per  cent., 
giving  *0188  gramme  carbonate  of  lime,  or  -526  per  cent,  of  lime. 
The  filtrate  from  the  lime  and  iron  precipitate  was  precipitated  with 
