314  On  the  Power  of  Soils  to  absorb  Manure. 
since  learnt,  that  Mr.  Thompson  had,  fully  three  years  ago, 
occupied  himself  with  a series  of  experiments  on  the  subject, 
and,  with  the  assistance  of  Mr.  Spence,  of  York,  had  arrived  at 
results  which  left  no  doubt  in  his  mind  that  soils  possess  a 
specific  power  for  the  detention  not  only  of  ammonia,  but  of  the 
salts  of  this  base.  Mr.  Thompson’s  experiments  are  published 
in  another  part  of  the  present  journal;  and  although,  had  the 
extent  of  his  inquiries  been  known  to  me  at  the  time  of  com- 
mencing my  experiments,  the  whole  subject  would  probably  have 
been  left  in  his  hands,  the  agricultural  public  has  in  the  perfect 
concordance  of  result  obtained  by  two  experimenters,  working  quite 
unknown  to  and  independently  of  each  other,  and  by  somewhat 
different  methods,  every  guarantee  of  the  perfect  accuracy  and 
truthfulness  of  that  result. 
It  is  particularly  important  in  the  present  case  that  such  a 
confirmation  of  the  facts  should  be  forthcoming  : as  although 
some  of  the  actions — such  as  that  of  soils  upon  the  colour  and 
smell  of  liquid  manure — may  be  demonstrated  by  very  simple 
experiments,  the  details  of  this  particular  investigation  are  too 
laborious  to  be  lightly  repeated,  and  the  great  mass  of  informa- 
tion must  be  received  upon  the  good  faith  of  the  operator  who 
has  made  and  described  the  experiments. 
It  will  be  observed  that  the  inquiry  has  extended  far  beyond 
the  question  of  the  absorption  of  ammonia,  and  that  the  other 
bases  have  been  found  amenable  to  a similar  law.  Some  attempt 
has  also  been  made  to  trace  the  cause  of  this  very  singular  action, 
and  with  a certain  amount  of  success  in  pointing  out  if  not  to 
what  it  is,  at  least  to  what  it  is  not,  to  be  attributed.  Much, 
however,  yet  remains  to  be  done  ; and  although  Mr.  Thompson’s 
experiments  and  those  now  to  be  described  place  beyond 
dispute  the  fact  that  soils  are  gifted  with  a remarkable  power  of 
separating  from  solution  and  retaining  the  salts  of  manure 
until  required  by  vegetation,  it  must  be  left  to  further  researches 
to  develope  the  precise  circumstances  and  conditions  in  which 
that  power  is  exerted ; such  inquiries  are  now  being  vigorously 
prosecuted,  and  there  is  every  hope  of  ultimate  success. 
The  power  of  soils  to  absorb  ammonia  from  the  air  is  well 
known.  Professor  Liebig,  in  his  admirable  work  on  Agricul- 
tural Chemistry,  has  brought  together  the  existing  knowledge 
upon  this  subject;  and  has  shown  that,  besides  being  brought 
down  to  the  soil  by  every  shower  of  rain,  ammonia  is  absorbed  by 
the  soil  from  the  atmosphere.  He  refers  this  property  to  the 
aluminous  and  ferruginous  compounds  of  the  soil,  which  are 
known  to  have  a peculiar  attraction  for  ammonia,  and  likens  it  to 
the  power  possessed  by  charcoal  to  condense  this  gas.  But  that 
Professor  Liebig  had  no  notion  that  soils  had  the  power  of 
