of  the  Ashes  of  Plants. 
515 
The  hop  plant,  it  appears,  is  peculiar  in  the  quantity  of  phos- 
phoric acid  required  for  all  its  different  parts;  in  this  respect  it 
far  exceeds  any  other  plant  which  we  have  examined.  It  may 
not  be  without  reason,  therefore,  that  the  value  of  land  which  is 
devoted  to  hops  has  been  referred  to  the  great  prevalence  in  it  of 
phosphate  of  liine.  The  chemical  history  of  the  greensand  district, 
which  is  principally  cultivated  in  hops,  has  been  fully  given  in  this 
Journal  (vol.  ix.  part  1,  Phosphoric  strata  of  the  Chalk  Formation)  ; 
and  it  is  interesting  to  observe  that  the  composition  of  the  hop  is 
such  as  to  bear  out  the  views  which  were  there  advanced. 
A calculation  of  the  mineral  matters  removed  from  an  acre  of 
land  by  the  crop  from  which  the  specimens  were  taken,  will  serve 
to  exhibit  the  exhausting  character  of  its  culture  in  relation  to 
other  plants. 
The  produce  of  two  hills  of  fair  average  was  collected — the  hills 
being  six  feet  apart,  or  1200  hills  to  an  acre. 
The  following  table  shows  the  quantity  of  produce  and  of 
mineral  matter  removed  per  acre  after  drying  at  150°: — 
Produce  from 
Produce 
Mineral  Matter 
2 Hills. 
per  Acre. 
per  Acre. 
lbs. 
lbs. 
lbs. 
Flowers  . 
.3-5 
2131  • 
• 170-43 
Leaves 
. 3-75  • . 
2250  . 
. 435-06 
Bine  . 
. 3-25  •• 
1987  • 
• 129*54 
It  will  be  here  observed  that  the  produce  in  hops  is  made  by 
the  experiment  on  the  two  hills  to  equal  nearly  a ton  per  acre ; 
in  effect  this  number  is  verified  by  the  result  on  the  large  scale — 
the  quantity  of  hops  obtained  from  23  acres  having  been  19  tons. 
The  crop  of  1848  was  almost  unprecedentedly  large,  which  must 
be  ever  borne  in  mind  in  the  consideration  of  the  table  which 
precedes  as  well  as  that  which  follows. 
Table  showing  the  quantity  of  Mineral  Matter  removed  by  the  above 
crop  of  Hops,  in  lbs.  and  tenths. 
Flowers. 
Leaves. 
Bine. 
Whole 
Crop. 
Silica 
lbs. 
32-6 
lbs. 
97-3 
Ib3. 
12*9' 
lbs. 
142-8 
Phosphoric  Acid  . . 
29-5 
40-6 
15-1 
85-2 
Sulphuric  Acid 
8-7 
8 2 
3-0 
19-9 
Carbonic  Acid  . 
3-4 
52-4 
15-4 
71-2 
Lime 
16-3 
134-0 
31-0 
181-3 
Magnesia  .... 
8-2 
21  - 1 
4-9 
34-2 
Peroxide  of  Iron 
1-1 
•8 
10 
2-9 
Potash 
54-0 
57-0 
22-9 
133-9 
Soda 
none. 
none. 
none. 
none. 
Chloride  of  Potassium  . 
15-3 
10-0 
19-9 
15-2 
Chloride  of  Sodium 
1-3 
13-0 
3-4 
18-3 
Total  . 
170-4 
435-0 
129-5 
734-9 
Were  the  numbers  in  this  table  applicable  to  the  ordinary 
