510 
Fourth  Report  on  the  Analysis 
so  that  the  numbers  are  capable  of  exact  application.  As 
before  stated,  in  the  analysis  no  separation  was  made  of  the 
leaves  and  stalks  or  the  envelope  of  the  seed,  so  that  these  three 
first  items  will  be  grouped  together.  The  table  below  gives  the 
quantity  of  mineral  matter  removed  by  an  pcre  of  “ Forty-day  ” 
maize  on  the  basis  of  Mr.  Keene’s  calculations. 
Mineral  Matters  removed  by  an  acre  of  “Forty-day”  Maize,  in  lbs.  and 
tenths  :■ — 
In  f>25  lbs. 
In  2409  lbs. 
On  the 
In  28801bs. 
of  the  Pith 
of  Stalks 
of  Grain. 
of  the 
“ Cobb.” 
and 
Leaves. 
Crop. 
Silica  ..... 
•6 
•82 
35-0 
36-4 
Phosphoric  Acid 
21-2 
•13 
10-1 
31-4 
Sulphuric  Acid 
• • 
•06 
6-4 
6*5 
Carbonic  Acid  • 
• • 
•23 
3-6 
3-8 
Lime 
•2 
•10 
13-2 
13-5 
Magnesia  .... 
5-4 
•12 
6-9 
12-4 
Peroxide  of  Iron  . . 
•2 
•01 
2-8 
3-0 
Potash 
11-2 
1-32 
44-1 
56-6 
Soda 
•7 
•24 
• • 
•9 
Chloride  of  Potassium  . 
• • 
• • 
• • 
• • 
Chloride  of  SodiunP 
• • 
•07 
2-9 
3-0 
Total  in  lbs.  . . 
39 '5 
3-10 
125-0 
167-5 
The  second  column  of  this  table  is  chiefly  interesting  from  the 
insignificance  of  the  mineral  matters  removed  by  the  pith  of  the 
cobbs.  This  part  of  the  maize-plant  is  relatively  small,  but 
actually  important  in  quantity.  It  is  used,  Mr.  Keene  informs  us, 
by  the  peasants  for  firing,  for  which  its  light  dry  character  well 
fits  it.  By  the  calculations  above  given,  it  would  appear  that 
every  acre  of  maize  would  yield  5 cwt.  of  this  fuel.  In  com- 
paring the  mineral  composition  of  maize  with  that  of  wheat,  we 
do  not  find  the  solution  of  the  question  lately  proposed. 
A crop  of  28  bushels  of  wheat  carries  off,  of  phosphoric  acid, — 
In  the  grain  ....  about  13  lbs. 
In  the  straw  ....  about  7 lbs. 
In  all  . . . 20  lbs. 
And  of  potash : — 
In  the  grain  ....  about  9 lbs. 
In  the  straw  ....  about  14  lbs. 
In  all  . . . 23  lbs. 
Whilst,  on  the  other  hand,  what  is  said  to  be  a fair  crop  of  maize 
requires  one-third  more  phosphoric  acid  and  times  the  quan- 
tity of  potash.  If  then  our  data  are  correct,  all  notion  of  attribut- 
ing the  relative  produce  of  the  two  plants  to  their  mineral  pecu- 
