On  the  Power  of  Soils  to  absorb  Manure. 
3G9 
Grains. 
Oxide  of  iron 5-20 
Lime  . . . 3 2a  18 
Carbonic  acid not  ascertained 
Sulphuric  acid 20*34 
Chloride  of  sodium  . . • . 86*78 
It  will  be  observed  that  the  quantity  of  lime  and  sulphuric  acid 
in  the  resulting  are,  within  errors  of  experiment,  the  same  as  in  the 
original  liquid ; the  quantity  of  chlorine  is  also  as  nearly  as  pos- 
sible the  same  in  both  liquids  ; but  in  the  original  flax-water  part 
of  it  was  in  combination  with  potassium,  which,  after  treatment 
with  clay,  has  been  replaced  by  sodium.  We  have  here  two  results 
which  were  unexpected  : the  first,  that  the  quantity  of  lime  should 
not  be  increased,  which  seems  opposed  to  the  principle  before  laid 
down,  that  lime  replaces  in  the  liquid  the  potash  and  magnesia 
previously  combined  with  sulphuric  and  muriatic  acids  ; the  second 
peculiarity  is  the  existence  in  the  resulting  solution  of  much  more 
soda  than  existed  in  the  flax- water  itself.  This  soda  can  only  have 
been  derived  from  the  clay,  which  we  find  from  the  analysis  (page 
320)  contains  the  alkali  in  considerable  quantity.  It  would  seem 
therefore,  that  in  the  present  instance  soda,  and  not  lime,  has  acted 
the  part  of  the  substituting  base.  It  is  useless,  at  this  stage  of  the 
investigation,  to  attempt  to  reconcile  these  apparent  inconsistencies, 
and  we  shall  pass  on  to  describe  an  experiment  made  upon  the 
filtration  of  the  water  of  a London  sewer  through  a bed  of  soil. 
The  sewer-water  employed  had  the  following  composition:  — 
Analysis  of  Sewer-water. 
Au  Imperial  Gallon  contains  (in  grains 
and  tenths) — 
Soluble. 
Insoluble. 
Both. 
Organic  Matter  and  Salts  of  Ammonia 
121*50 
ISO -32 
301*82 
Sand  and  Detritus  of  the  Granite  from  the  Streets 
*1-39 
19*30 
20*69 
Soluble  Silica  .... 
1*57 
10*94 
12*51 
Phosphoric  Acid  . , . 
7*71 
2*73 
10*44 
Sulphuric  Acid  . , . 
10*71 
4-02 
14*73 
Carbonic  Acid  , . . 
11*62 
3*97 
15*59 
Lime  , . . 
7*50 
17*03 
24*53 
Magnesia  . . 
2*87 
Traces. 
2*87 
Peroxide  of  Iron  and  Alumina  . 
Traces. 
6*20 
6*20 
Potash  ... 
46*91 
1 *22 
48*13 
Soda  . , , 
None. 
1*51 
1*51 
Chloride  of  Potassium  . 
None. 
None. 
None. 
Chloride  of  Sodium  ... 
31*52 
1*72 
33*24 
243*30 
248*96 
492*26 
* This  is  some  small  proportion  of  insoluble  matter  escaping  the  linen  filter,  and 
properly  belonging  to  the  other  column. 
VOL.  XI.  2 B 
