CHLORIDE  OF  POTASSIUM  FROM  CARNALLITE.  317 
had  lost  so  much  potassa.  It  is  now  not  essential  to  put  car- 
bonate of  potassa  upon  the  land,  although  this  occurs  chiefly  in 
the  ashes  of  plants.  A  soil  containing  alumina  and  lime  has 
the  wonderful  property  of  taking  up  sulphate  of  potash  and 
chloride  of  potassium  and  rendering  them  insoluble  in  water, 
while  the  acids  combine  with  the  lime  or  magnesia  in  the  soil. 
But  since  chloride  of  calcium  and  chloride  of  magnesium  pass 
into  the  juice  of  the  beet,  and  obstruct  the  clarifying  of  the 
sugar,  it  is  better  to  apply  the  sulphate  of  potassa  instead  of  the 
chloride  of  potassium,  since  the  sulphate  of  lime  thus  produced 
does  not  have  an  injurious  influence,  but,  on  the  contrary,  is  of 
advantage,  since  it  affords  to  the  plant  the  necessary  sulphur, 
retains  the  ammonia,  and  changes  the  silicate  of  potassa  in  the 
soil  into  soluble  sulphate  of  potassa.  It  is  therefore  to  be  de- 
sired that  the  application  of  sulphate  of  potassa  may  be  encou- 
raged, since  the  business  at  Stassfurth  may  thus  be  helped,  and 
the  deposit  in  that  place  become  a  blessing  to  agriculture. 
Carnallite  looks  very  much  like  rock  salt,  but  is  generally 
colored  red  by  oxide  of  iron.  When  it  is  exposed  to  the  air  it 
deliquesces,  and  cannot  therefore  well  be  preserved.  It  is  conse- 
quently stored  in  the  mine,  which  fortunately  is  of  ample  dimen- 
sions. The  quantity  wanted  in  the  factories  is  ordered  day  by 
day,  and  sent  directly  to  the  dissolving  vessels,  in  covered  cars 
by  railway.  A  few  manufacturers  use  the  carnallite  coarsely 
ground.  The  grinding  is  done  under  the  care  of  the  director  of 
the  mine,  and  large  iron  mills,  like  coffee  mills,  of  four-tenths  of 
a  metre  in  diameter  are  used.  One  such  mill  in  24  hours  will 
grind  about  30  tons,  of  1000  kilogrammes  each.  A  sample  is 
taken  from  each  car  load,  and  its  percentage  of  chloride  of  po- 
tassium ascertained.  The  factories  received  in  1864,  from  the 
two  mines  at  Stassfurth  and  Anhalt,  125,000  tons  of  carnallite, 
which  had  the  following  average  composition  : 
Chloride  of  potassium,  17*5  per  cent.  (15 — 20.) 
Chloride  of  sodium,  22* 
Chloride  of  magnesium,  23-5 
Sulphate  of  magnesia,  9- 
Water,  ~  28- 
100- 
