770  Miscellaneous  Results  from  the  Laboratory . 
of  a city  are,  for  the  most  part,  removed  from  the  residences  of 
the  wealthier  classes;  and  further,  that  the  supply  of  water  is 
generally  intermittent,  it  will  be  seen  that  the  composition  of 
water  taken  from  any  one  sewer  can  only  serve  to  show  the 
general  nature  of  the  loss  which  agriculture  sustains  from  our 
present  system  of  town  sewerage  without  affording  the  data  by 
which  that  loss  could  be  estimated  with  any  degree  of  accuracy. 
The  following  analyses  of  sewer  water  will,  however,  serve  to 
place  palpably  before  the  farmer  the  value  of  a liquid  which 
(however  difficult  the  problem  in  cities  like  London)  might  cer- 
tainly with  great  ease  be  saved  and  utilized  by  many  of  the 
moderate-sized  towns  and  larger  villages  throughout  the  United 
Kingdom. 
The  specimens  of  sewer  water  were  supplied  to  me  by  the 
Commission  of  Sewers,  at  the  request  of  the  General  Board  of 
Health;  they  were  taken  from  a sewer  in  Dorset  Square,  and 
another  in  a place  called  Barrett’s  Court.  The  liquid  in  both 
cases  was  fetid  and  offensive  to  the  smell,  and  of  a dirty  black 
colour  ; sulphuretted  hydrogen  gas  was  given  off  from  it  in 
sensible  quantity. 
The  matter  in  suspension  and  that  in  solution  were  separately 
analyzed — the  following  was  the  quantity  of  each  in  an  imperial 
gallon  of  the  specimens  : — 
No.  1. — Sewer  Water  from  Barrett's  Court. 
An  imperial  gallon  contained — 
Of  substances  in  solution  . . . 243'30  grains. 
Of  insoluble  substances  . . . 248 '96  „ 
No.  2. — Sewer  Water  from  Dorset  Square. 
The  imperial  gallon  contained — 
Of  substances  in  solution  . . . lOO’OO  grains. 
Of  insoluble  substances  . . 100’70  „ 
The  insoluble  matter,  as  will  be  seen,  consisted  partly  of  sand 
and  the  dust  of  the  granite  or  other  paving — the  organic  portion 
contained  the  cells  of  different  vegetables,  hair,  fragments  of 
paper,  &c. 
The  following  tables  give  the  composition  of  the  liquid  and 
solid  matter  of  these  specimens  of  sewer  water  : — 
The  insoluble  and  soluble  matters  are  both  capable  of  sup- 
plying nitrogen  or  ammonia  to  vegetation.  The  solution  contains 
the  nitrogen  in  the  form  of  ammoniacal  salts,  and  it  is  a circum- 
stance of  great  interest  and  practical  importance  that  all  the 
nitrogen  in  the  liquid  state  seems  to  be  in  the  form  of  ammoniacal 
salts — the  urea  and  other  animal  products  having  rapidly  passed 
into  this  condition.  The  insoluble  matter  contains,  of  course,  no 
ammoniacal  salts,  its  nitrogen  being  referable  to  unchanged 
animal  matters.  The  quantity  of  ammonia  in  the  soluble  and 
insoluble  state  in  a gallon  of  sew7er  water,  calculating  the  nitrogen 
