On  the  Power  of  Soils  to  absorb  Manure. 
343 
Solution  3988  grains'!  Digested,  however,  for  a shorter  period — 
Soil  . 594  , , / namely,  half  an  hour. 
1st  Distillation  of  the  Product — 
Grains. 
158-02 
gave 
Platinum  Salt. 
5-49  = 
Ammonia. 
•41855 
or 
Per  Cent. 
•2649 
2nd  Distillation — 
146-68 
gave 
5-14  = 
•39187 
or 
•2671 
3rd  Distillation — 
179-29 
gave 
6-26  = 
•47726 
or 
•2662 
1st  Distillation  ... 
■2649  per  Cent. 
2nd  ,,  ...  *2671  ,, 
3rd  ,,  ...  -2662  ,, 
Mean.  . . ‘2661  ,, 
100  grains  of  the  original  liquid  contained  . *3173  grains  of  Ammonia. 
100  grains  of  the  resulting  liquid  contained  '2661  ,,  ,, 
Loss  by  each  100  grains  of  Solution  . . *0512 
The  whole  quantity  of  solution  (3988  grains)  would  therefore  have  lost 
2* 0418  grains  of  ammonia,  which,  being  absorbed  by  594  grains  of  soil, 
makes  the  absorption  • 3438  per  cent. 
In  the  last  experiment  the  absorption,  with  corresponding 
quantities  of  soil  and  solution,  was  found  to  be  ‘3584  per  cent. ; 
the  difference  between  the  two  results  is,  therefore,  only  to  the 
extent  of  t „%  0-  of  a grain,  and  would  have  been  much  less  if 
the  mean  of  the  1st  and  3rd  of  the  last  estimations  of  ammonia 
had  been  taken  as  the  true  result. 
In  order  to  ascertain  whether  any  difference  in  the  amount  of 
the  absorption  would  be  caused  by  longer  contact  of  the  soil  with 
the  solution,  the  quantity  remaining  from  the  last  experiment  was 
left  to  digest  upon  the  soil  for  fourteen  or  sixteen  hours  longer, 
the  bottle  being  repeatedly  shaken.  The  following  result  was 
then  obtained  by  examining  the  solution  : — 
4th  Distillation — 
Grains.  Platinum  Salt.  Ammonia.  Per  Cent. 
145’ 49  gave  4*93  = *3758  or  *2652 
This  result  is  almost  identical  with  that  obtained  when  the 
liquid  had  only  been  digested  with  the  soil  for  half  an  hour  ; and 
also  with  the  previous  one,  in  which  the  digestion  had  been  con- 
tinued for  two  hours.  It  is  obvious,  therefore,  that  a longer 
duration  of  the  experiment  than  half-an-liour  is  quite  unneces- 
sary, as  the  full  effect  occurs  within  that  time. 
It  has  already  been  shown  (experiments  8,  9,  10,  and  11)  that 
a great  amount  of  absorption  takes  place  almost  instantaneously, 
and,  from  the  experiments  that  have  just  been  described,  there  is 
little  doubt  that  the  perfect  union  of  the  soil  with  the  alkaline  sub- 
stance is  as  rapidly  produced  as  the  ordinary  combination  of  an 
acid  and  a base.  It  will  be  sufficient  to  call  attention  to  this  point 
