313 
On  Draining  Clay  Soils  too  deep. 
which,  drain  it  as  you  will,  you  could  regularly  grow  and  feed 
off  a turnip  crop.  Besides,  the  depth  of  soil  is  a material  point 
hitherto  overlooked.  On  the  Oxford  clay,  the  strongest  of  all 
clays,  you  may  have  two  feet  of  good  soil,  or  you  may  have,  as  I 
know  to  my  cost,  literally  no  soil  at  all.  Now  since  a good  soil 
may  be  regarded  as  absolutely  porous,  the  depth  of  four  feet  for  a 
drain,  though  nominally  the  same,  will  be  really  twice  as  great 
in  the  latter  as  in  the  former  case.  In  taking  leave  of  the  subject, 
I must  say  that  while  the  advocates  of  deep  draining  have  ren- 
dered us  most  essential  service,  Mr.  Parkes,  by  bringing  it  into 
notice,  and  another  writer  recently,  by  eloquently  advocating  it  in 
a periodical  journal,  Mr.  Webster  has  done  service  also  in  pro- 
ving the  need  of  caution  upon  certain  exceptional  clays.  The 
discussion  has  helped  to  draw  attention  to  this  important  subject, 
and  it  was  said  to  me  long  since  by  the  late  lamented  Lord 
Spencer,  that  the  best  thing  for  draining  would  be  a controversy 
on  the  depth  at  which  drains  should  be  cut. 
Ph.  Pusey. 
XXI. — On  the  Power  of  Soils  to  absorb  Manure.  By  J.  Thomas 
Way,  Consulting  Chemist  to  the  Society. 
In  the  paper  which  is  now  placed  before  the  members  of  the 
Society,  an  attempt  has  been  made  to  develope,  in  part  at  least, 
a newly  observed  property  of  soils,  which  will,  in  all  probability, 
prove  of  great  importance  in  modifying  the  theory  and  in  con- 
firming or  improving  the  practice  of  many  agricultural  operations. 
The  investigation,  which  has  now  occupied  many  months  of  my 
personal  attention,  took  its  rise  in  observations  made  to  me  fully 
two  years  ago  by  Mr.  Huxtable  and  Mr.  PI.  S.  Thompson. 
The  former  of  these  gentlemen  stated  that  he  had  made  an 
experiment  in  the  filtration  of  the  liquid  manure  in  his  tanks 
through  a bed  of  an  ordinary  loamy  soil ; and  that  after  its 
passage  through  the  filter-bed,  the  urine  was  found  to  be  deprived 
of  colour  and  smell — in  fact,  that  it  went  in  manure  and  came 
out  water.  This,  of  itself,  was  a singular  and  interesting  observa- 
tion, implying,  as  it  did,  the  power  of  the  soil  to  separate  from 
solution  those  organic  substances  which  give  colour  and  offensive 
smell  to  putrid  animal  liquids. 
Mr.  Thompson,  about  the  same  time,  mentioned  to  me 
that  he  had  found  that  soils  have  the  faculty  of  separating 
ammonia  from  its  solution  : a fact  appearing  still  more  extraor- 
dinary, inasmuch  as  there  is  no  ordinary  form  of  combination  by 
which  we  could  conceive  ammonia  to  become  combined  in  a state 
of  insolubility  in  the  soil.  At  the  time  I was  not  aware,  as  I have 
