On  the  Power  of  Soils  to  absorb  Manure.  363 
The  whole  quantity  of  lime-water  would  therefore  have  lost  1 ’468  grains 
lime;  and  since  100  grains  of  clay  was  employed  in  the  experiment,  the 
per-centage  absorption  is  the  same  number,  or  1-4G8  per  cent. 
Experiment  90. — 2000  grains  of  the  same  lime-water,  diluted  with  6000 
grains  of  distilled  water,  and  well  washed  carbonic  acid,  passed  through 
the  solution  as  before.  The  object  of  diluting  the  solution  was  to  prevent 
separation  of  the  crystalline  bi-carbonate,  which  occurs  when  the  lime 
water  is  too  strong. 
\VhiWbchySOlUti°n  °f  bi'Carb°na,e  ‘ 8<f0J  gra!nS-  } Digested  together  for  2 hours. 
The  lime  in  the  whole  quantity  of  the  original  solution  was  . 2-  422  grains. 
In  the  whole  quantity  of  the  resulting  solution  ....  1 • 601  ,, 
The  difference  being *731  , , 
— which  is  the  absorption  by  10U  grains  of  clay. 
Experiment  91. — Lime-water  and  clay. — In  this  experiment  a solution 
of  lime  containing  1-052  of  lime  in  every  1000  grains  was  employed. 
Lime  water  . . . 3500  grains. 
White  clay  . . . 100 
The  whole  quantity  of  the  original  solution  contained 
The  whole  quantity  of  the  resulting  solution  . . 
| Digested 
together  for  24  hours. 
3 ’684  grains. 
2-567 
The  difference  being  1-117  ,, 
—which  is  consequently  the  absorption  by  100  grains  of  clay. 
In  the  three  last  experiments  a great  increase  of  the  absorptive 
power  is  observed,  the  quantity  of  lime  absorbed  by  100  grains 
of  clay  being  something  very  considerable. 
That  the  absorption  of  the  bi-carbonate  of  lime  by  the  clay  is 
due  to  an  action  entirely  different  from  that  which  causes  the 
detention  of  lime  itself,  has ’before  been  remarked.  The  soluble 
bi-carbonate  of  lime  is  an  acid  salt,  and  it  is  obvious  that  to  arrest 
and  combine  with  it  the  soil  must  offer  to  the  excess  of  carbonic 
acid  some  saturating  base.  I have  every  reason  to  believe  that 
clay  (and  soils  generally,  in  virtue  of  clay)  contains  lime  in  a form 
which  is  available  for  the  neutralization  of  the  bi-carbonate  of 
lime,  which  is  thus  converted  into  the  ordinary  insoluble  carbon- 
ate ; and  there  is  much  ground  for  hope  that  the  theory  of  liming, 
as  a means  of  renovating  and  improving  the  soil,  will  receive 
much  explanation  from  the  further  investigation  of  this  most 
interesting  branch  of  the  subject. 
Absorption  of  Magnesia  and  Soda. — No  very  definite  experi- 
ments on  the  extent  of  the  power  of  soils  to  arrest  these  bases 
have  as  yet  been  made. 
Absorption  of  Organic  Matters. — Hitherto  we  have  confined 
our  attention  to  the  mineral  ingredients  of  manure,  but  the 
absorptive  power  of  soils  extends  also  to  the  detention  of  or- 
ganic matters.  In  the  early  part  of  this  paper  it  was  stated 
that  Mr.  Huxtable  had  observed  and  related  to  the  author  the 
