524 
Fourth  Report  on  the  Analysis 
perfection,  and  contradistinguished  from  the  ultimate  exhaustion, 
which  is  regulated  by  the  proportion  of  these  matters  eventually 
restored  in  the  manure  into  which  they  are  converted. 
40  cwt.  of  fine  flax  straw  at  3 • 27  per  cent,  of  ash  will  contain  140 ‘5  lbs.  of  ash. 
10  cwt.  of  seed  at  2 • 99  per  cent,  of  ash  (which  is  the  mean  per  centage  of  the 
two  specimens  examined)  will  contain  33*5  lbs.  of  ash. 
9 cwt.  of  bolls  or  husks  at  6*39  per  cent,  of  ash  will  contain  64*4  lbs.  of  ash. 
These  ashes  will  consist  respectively  of  the  following  mineral 
matters : — 
Mineral  Matters  in  lbs.  and  tenths  removed  by  an  Acre  of  Flax : — 
In  2 tons  of 
In  20  bushels 
In  9 cwt.  of 
In  the  entire 
Flax  Straw. 
of  Linseed. 
Bolls. 
Crop. 
Silica 
11-6 
•5 
10-0 
22-1 
Phosphoric  Acid  . . 
11-0 
12-9 
1-7 
25-6 
Sulphuric  Acid  . • 
5-0 
•5 
2-7 
8-2 
Carbonic  Acid  . 
23*1 
• • 
6-5 
29-6 
Lime 
31  • 1 
2-8 
17-2 
51-1 
Magnesia  .... 
6-1 
4-4 
1-6 
12-1 
Peroxide  of  Iron  . . 
8-2 
*2 
1-3 
9-7 
Potash 
31-5 
11-4 
16-6 
59-5 
Soda 
5-4 
•6 
• • 
6-0 
Chloride  of  Potassium  . 
• . 
• . 
2-2 
2-2 
Chloride  of  Sodium  . 
13-5 
•2 
4-6 
18-3 
Total  .... 
146-5 
33-5 
64-4 
244-4 
The  immediate  effect  of  such  a crop  in  exhausting  the  mineral 
matters  of  the  soil  in  which  it  grows,  is  then  (in  all  ingredients 
save  silica)  considerably  greater  than  that  of  any  of  the  corn- 
crops — it  contains  one-fourth  more  phosphoric  acid  and  twice  as 
much  potash  as  an  average  acre  of  wheat — this  circumstance  is 
doubtless  important  as  a guide  in  preparing  the  land  for  the 
growth  of  the  flax,  but  it  will  have  no  further  objectionable 
import  if  it  can  be  shown  that,  in  the  ordinary  course,  the  greater 
part  of  the  mineral  matter  is  (or  readily  might  be)  restored  to  the 
soil.  The  term  exhaustion,  in  reference  to  mineral  matters,  can 
\have  no  real  meaning  in  such  a case.  Is  it  ever  objected  to  a 
crop  of  turnips  or  mangold  that  they  are  exhausting?  and  yet 
both  of  these  plants  take  from  the  soil  twice  the  quantity  of 
important  minerals  that  a wheat  or  barley  crop  would.  But 
being  in  great  part  or  entirely  consumed  on  the  land,  or  at  all 
events  remaining  upon  the  farm,  and  being  eventually  returned 
in  the  shape  of  manure,  the  phosphoric  acid  and  potash  (with 
certain  exceptions)  are  really  not  removed — the  land  is  really  not 
exhausted  of  them. 
The  mineral  matters  of  the  linseed  and  of  the  seed-capsules 
find  their  way  readily  back  to  the  soil  in  the  shape  of  manure. 
It  remains  now  to  trace  those  which  are  contained  in  the  flax- 
