370 
On  the  Power  of  Soils  to  absorb  Manure. 
It  also  contained  nitrogen,  the  greater  part  of  which  existed  in  the  form 
of  ammonia,  whilst  a small  portion  was  present  in  the  solid  animal  and 
vegetable  matters  of  the  sewer  water. 
Ammonia,  in  a gallon,  41'28  grains,' of  which  3672  actually  existed  as 
ammonia. 
The  filter  through  which  this  sewer-water  was  passed  consisted  of  4 lbs. 
of  Mr.  Pusey’s  soil  placed  in  a glass  cylinder,  which  it  filled  to  the  depth 
of  6 inches.  The  liquid  began  to  pass  through  in  about  ten  minutes,  and 
in  two  hours  about  half  a gallon  (5  lbs.)  was  collected.  The  filtration  had 
deprived  it  of  colour  and  smell.  The  insoluble  matter  of  the  sewer-water 
was,  of  course,  arrested  mechanically,  being  in  great  part  found  as  a black 
slime  on  the  top  of  the  soil.  Upon  analysis,  a gallon  of  the  filtered  liquid 
was  found  to  contain  248-50  grains  of  solid  matter,  consisting  of— 
Organic  matter,  destitute  of  nitrogen 
Grains. 
. 60-58 
Chloride  of  sodium 
. 52-73 
Chloride  of  magnesium 
. -67 
Chloride  of  calcium  .... 
. 8-89 
Carbonate  of  lime 
. 104-98 
Sulphate  of  lime 
. 17-49 
Loss  on  the  analysis  .... 
. 3-16 
248-50 
The  filtered  liquid  contained  no  potash,  no  ammonia  or  nitrogen 
in  any  form,  no  phosphoric  acid,  and  a much  reduced  quantity  of 
magnesia.  There  is  an  excess  of  chloride  of  sodium  in  the 
filtered  liquid,  which  can  have  only  been  derived  from  the  soil, 
although  the  analysis  (given  at  page  319)  failed  to  denote  its 
presence.  This  will  not  surprise  us  when  we  remember  that  the 
20  grains  of  common  salt  has  been  obtained  from  10  lbs.  (or 
70,000  grains)  of  soil,  so  that  100  grains  of  soil  would  contain 
only  about  -,-fo-ths  of  a grain  of  common  salt,  which  might  easily 
escape  notice.*  It  will  be  observed  that  the  total  solid  contents 
of  a gallon  of  the  sewer-water  is  greater  after  filtration  than  before 
— a circumstance  which  is  due  to  the  presence  of  a large  quantity 
of  carbonate  of  lime,  which  seems  to  have  been  dissolved  by  the 
free  carbonic  acid  generated  in  the  sewer-water  by  the  gradual 
decomposition  of  its  organic  contents.  We  find  in  the  present 
case  that  the  soluble  organic  matter  is  reduced  by  one  halt  ; that 
which  remains  has  a peculiar  smell  resembling  honey,  and  burns 
with  a bright  flame  as  wax  or  grtease  would,  but  what  its  exact 
composition  is  has  not  been  ascertained,  further  than  that,  as  be- 
fore mentioned,  it  contains  no  nitrogen. 
This  experiment,  on  the  whole,  is  most  gratifying.  Inde- 
pendently of  the  matters  which  are  mechanically  arrested,  we 
find  that  the  soil  retains  the  greater  part — in-  most  cases  the 
* The  method  of  filtration,  operating  upon  a large  quantity  of  soil  through  which 
distilled  water  should  he  passed,  might  very  usefully  be  practised  in  the  analysis  of 
soils,  for  the  determination  of  those  ingredients  which  are  soluble  in  water,  where  they 
exist  in  very  small  quantity. 
