212  Crab-Orchard  Salt.  {^VaTi^m^' 
salt  dissolved  in  very  little  water,  phosphate  of  ammonia  added,  and 
the  liquid  evaporated  to  dryness.  The  dry  salt  was  treated  with  am- 
monia water,  allowed  to  stand  over  night,  filtered  off  and  the  phos- 
phate of  lithia  washed  with  ammonia  water.  It  was  carefully  ignited 
and  weighed,  giving  -0420  gramme  of  phosphate  of  lithia,  equal  to 
•008  per  cent,  of  lithia.  For  an  easier  examination  with  the  spectro- 
scope, the  phosphate  of  lithia  was  dissolved  in  a  few  drops  of  nitric 
acid,  (diluted.)  and  evaporated  to  dryness  with  a  small  excess  of  mer- 
curic oxide,  the  dry  mass  was  moistened  with  water,  and  again  evapo- 
rated to  dryness  ;  being  again  dissolved,  the  phosphate  of  mercury 
was  filtered  off,  the  filtrate  freed  from  mercury  by  sulphhydric  acid,, 
and  the  nitrate  of  lithia  evaporated  to  dryness  ;  and  was  proved  by 
the  spectroscope  to  be  perfectly  pure  lithia.  One  gramme,  after 
ignition,  was  moistened  with  a  few  drops  of  dilute  sulphuric  acid;  the 
excess  driven  off  by  heating  to  redness.  After  deducting  '0052 
gramme  for  insoluble  matter  and  ferric  oxide,  the  sulphates  of  mag- 
nesia, lime,  soda  and  potassa  and  lithia  weighed  -5494  gramme.  The 
magnesia  was  determined  in  this  mixture,  and  found  to  be  14*800 
per  cent.  The  mean  of  the  two  magnesia  determinations  is,  there- 
fore, 14-926  per  cent.,  calculating  the  values  found  for  magnesia, 
lime,  potassa  and  lithia,  as  sulphates,  it  gives  -47955  gramme,  leaving  , 
for  sulphate  of  soda  -6985  gramme,  equal  to  3  050  per  cent  of  soda. 
From  these  results,  the  analysis  of  Crab  Orchard  salt  would  be  as 
follows : — 
Water,  on  drying  over  sulphuric  acid,  .       .    6-030  "] 
"  expelled  at  120O  C,  ....  25-570  \  44-550 
"      and  organic  matter  on  ignition,             .       .  12'950  J 
Insoluble  matter,  (Fe2  03,Mn2  Oa,  Al^  0:5,  Mg,Ca,  SiOa,  0,CaFl,)       .  0.380 
Sesquioxide  of  iron,   0*140 
Magnesia,   15-052 
Lime,   0-526 
Lithia,   0-008 
Soda,   3  050 
Potassa,   1-012 
Rubidia,  a  trace. 
Chlorine,   0-291 
Sulphuric  acid,       .       .                                                        ,       .  35-379 
100-388 
Less  equivalent  of  oxygen  for  chlorine,   0  066 
100-322 
