110 
Improvement  of  Land  by  Warping. 
Soluble  salts  of  river  water  ....... 
Organic  matters,  containing  of  nitrogen  5f  tons  .... 
Carbonate  of  lime,  containing  of  lime  74  tons  2 cwts. 
Carbonate  of  magnesia,  containing  44  tons  15  cwts.  of  magnesia 
Alkalis  .......... 
Lime  ........... 
Magnesia  .......... 
Phosphoric  acid  ......... 
Silicic  acid,  sand,  oxide  of  iron,  and  other  comparatively  inert  sub- 
stances .......... 
Tons. 
Cwts. 
47 
12£ 
170 
16i 
103 
19 
74 
11 
5 
n 
11 
2 
48 
11 
7 
16 
1016 
101 
Now,  a six  years’  rotation  consisting  of  one  crop  of  beans,  two 
crops  of  oats,  and  three  of  wheat,  according  to  the  preceding 
analyses  (D),  would  only  remove  of — 
40  Bushels 
128  Bushels 
90|  Bushels 
of  Beans, 
of  Oats, 
of  Wheat, 
weighin 
g 2000. 
weighing  5120. 
weighing  5985. 
lbs. 
ozs. 
lbs. 
ozs. 
lbs. 
ozs. 
Sulphuric  acitl 
• 
• 
i 
12 
1 
8 
0 
3 
Phosphoric  acid 
• 
23 
12f 
25 
51 
53 
5f 
Potash  .... 
15 
15 
20 
15 
30 
lOf 
Soda  .... 
i 
13 
10 
10 
4f 
13 
Of 
Chloride  of  sodium 
• 
# 
1 
6f 
2 
14 
0 
15 
Lime  .... 
. 
# 
2 
Of 
6 
0 
1 
5 
Magnesia 
• 
6 
4i 
13 
6 
13 
3f 
Oxide  of  iron  . 
• 
0 
Of 
• 
• 
• 
Silicic  acid  . . . 
• 
0 
Of 
63 
5 
0 
3 
Inorganic  constituents  . 
• 
• 
64 
13f 
143 
10 
112 
13f 
Nitrogen  , 
• 
• . 
71 
3 
86 
1 
126 
12* 
— A quantity  which  will  hardly  admit  of  comparison  with  that 
added  to  the  land  in  the  form  of  manure.  We  can  now  under- 
stand how  it  is  that  warped  land  will  allow  of  crop  after  crop  of 
the  most  exhausting  cereals  being  raised  upon  it  without  exhibit- 
ing symptoms  of  exhaustion.  The  above  rotation,  indeed,  might 
be  repeated  more  than  thirty  times,  without  the  employment  of 
any  manure  whatever,  before  the  quantity  of  nitrogen  and  phos- 
phoric acid — the  two  most  important  constituents  of  the  soil — 
would  be  sensibly  affected. 
It  must  not  be  supposed,  however,  that  I should  wish  the 
reader  to  understand  that  the  entire  value  of  the  warp  as  a manure 
depends  upon  its  chemical  constituents,  upon  the  proportion  of 
nitrogen,  phosphoric  acid,  and  alkalis,  &c.,  which  it  contains. 
In  many  cases,  doubtless,  one  of  the  principal  advantages  that 
accrue  to  land  so  treated  is  caused  by  the  alteration  which  is 
effected  in  its  physical  properties,  in  its  porosity,  its  capability  of 
* In  this  calculation  I have,  of  course,  not  taken  into  consideration  the  inorganic 
constituents,  &c.,  of  the  straw,  as  it  was  supposed  that  these  would  necessarily  be  returned 
to  the  soil  in  some  shape  or  other  during  the  course  of  cultivation. 
