154  A  New  Source  of  Potash  Supply.     {k\*Ti  £K" 
full  measure  of  usefulness  for  other  purposes  before  it  comes  into  the 
hands  of  the  manufacturer  of  potash. 
But  the  questions  may  be  raised,  how  can  these  cobs  be  collected 
in  quantities  sufficiently  large  to  pay  for  working  them,  and  is  the 
supply  sufficiently  large  to  be  of  any  commercial  importance  ?  The 
first  question  is  easily  answered,  for  they  are  already  collected  at  the 
shipping  points  of  the  growing  districts,  where  large  shelling  mills, 
capable  of  running  through  500  bushels  ears  of  corn  an  hour,  are  es- 
tablished ;  here,  then,  are  the  places  where  a  supply  of  cobs  may  be 
procured.  The  figures  below  will  show  with  what  rapidity  they  accu- 
mulate. 
A  bushel  of  corn  weighs  70  pounds  on  the  cob  ;  a  bushel  of  shelled 
corn  weighs  56  pounds,  leaving  a  balance  of  14  pounds  cobs  to  the 
bushel ;  and  a  mill,  shelling  500  bushels  an  hour,  turns  out  7,000 
pounds  cobs  an  hour,  or  equal  to  70,000  pounds  per  working  day  of 
ten  hours.  As  many  of  these  cobs  as  are  necessary  are  used  for  the 
purpose  of  generating  steam  to  run  the  shelling-mills ;  the  surplus  is 
sold,  given  away  or  even  cast  out  into  waste  places  to  decay.  By 
collecting  the  ashes  from  these  waste  cobs,  together  with  the  ashes 
from  the  furnaces,  it  will  be  readily  seen,  by  reference  to  the  preced- 
ing analyses,  what  large  quantities  of  potash  salts  may  be  produced 
from  these  now  worthless  cobs. 
That  the  supply  of  cobs  can  never  fail,  the  following  statistics  will 
show  : 
The  corn  crop  of  the  United  States,  for  1870,  was  1,094,000,000 
bushels,  of  which  amount 
Illinois  yielded   201,378,000  bushels. 
Indiana    "  113,150,000  " 
Missouri  "    94,990,000  " 
Iowa        "   93,415,000  " 
Making  a  total  of  ....       502,933,000  " 
in  four  States  alone. 
The  corn  crop  of  the  whole  country,  for  1871,  was  1,100,000,000 
bushels,  which,  at  14  pounds  cobs  to  the  bushel,  will  yield  15,400,- 
000,000  pounds,  or  7,700,000  tons  cobs,  containing  an  average  of 
three-quarter  per  cent,  pure  carbonate  potassa.  We  have  the  enormous 
quantity  of  115,500,000  pounds  of  that  valuable  alkali  lost  to  com- 
merce annually,  which,  if  thrown  into  trade,  would  add  very  largely 
to  the  general  resources  of  the  country. 
