On  the  Power  of  Soils  to  absorb  Manure. 
34  7 
like  Mr.  Huxtable’s,  it  will  be  better  to  defer  the  comparison 
till  after  the  experiments  have  been  recounted.  In  the  preli- 
minary experiments  we  were  led  to  believe  that  the  addition  of 
chalk  to  a soil  did  not  increase  its  absorbent  power : in  other 
words,  that  the  carbonate  of  lime  either  was  unnecessary  to  the 
exhibition  of  the  absorptive  faculty  ; or  that,  if  necessary,  it  existed 
in  the  soils  examined  in  sufficient  quantity.  The  experiment  now 
to  be  described  throws  much  light  on  this  point : — 
Experiment  70.— Pipe-clay,  muriate  of  ammonia,  and  chalk — 
Solution  of  Muriate  ....  4000  grains. 
Pipe-clay  ......  400  , , 
Chalk 50  , , 
The  pipe-clay  and  the  chalk  were  well  mixed  in  a mortar,  having  both 
previously  passed  through  a sieve  of  40  holes  to  the  inch. 
The  materials  were  digested  together  for  two  hours. 
1st  Distillation  of  the  resulting  Liquid — 
Grains.  Platinum  Salt.  Ammonia.  Per  Cent. 
245-59  gave  8-93  = -68082  or  *2772 
2nd  Distillation — 
180-17  gave  6-58  = -50165  or  -2784 
1st  Experiment  . • . *2772  per  Cent. 
2nd  ,,  ...  -2784  ,, 
Mean  ....  -2778  ,, 
100  grains  of  the  original  Liquid  contained  -3000  grains  of  Ammonia. 
100  grains  of  the  resulting  Liquid  contained  *2778  ,,  ,, 
Loss  hy  each  100  grains  of  Solution  . -0282  ,,  , , 
The  whole  quantity  of  solution  (4000  grains)  has  therefore  lost  1*1280 
grains  of  ammonia,  which  has  been  absorbed  by  400  grains  of  clay,  making 
the  absorption  by  100  grains  of  clay  to  be  *2820. 
The  quantity  of  ammonia  absorbed  from  the  muriate  by  the 
clay  alone  was  *2847  per  cent. 
When  chalk  is  added,  the  absorption  is  found  to  be  *2820  per 
cent.,  which,  allowing  for  necessary  errors  of  experiment,  is 
obviously  the  same  quantity.  Now,  it  will  be  remembered  (see 
Analysis,  p.  320),  that  this  clay,  although  containing  lime,  does 
not  give  a perceptible  indication  of  the  presence  of  the  base  in  the 
state  of  carbonate.  But  notwithstanding  this,  we  find  that  the 
addition  of  carbonate  of  lime  to  the  clay  in  no  degree  increases 
its  power  to  combine  with  ammonia.  This  is  one  of  the  best 
instances  that  could  be  adduced  in  proof  of  the  belief  that  car- 
bonate of  lime  is  not  an  agent — or  perhaps  it  would  be  better 
said,  not  a direct  agent — in  their  transformation. 
In  the  last  experiment  it  will  be  observed  that,  in  order  to  give 
a greater  uniformity  and  a facility  of  comparison  to  the  results, 
the  quantity  of  absorbing  substance  was  made  to  bear  a definite 
relation  to  the  solution.  It  was  obvious,  however,  at  this  time 
