386 
Phosphorus. 
which  is  said  likewise  to  fertilise.  Water,  too,  containing  carbonic 
acid, has  a special  effect  upon  grass  * The  question,  we  shall  see,  has 
a vital  bearing  on  the  use  of  liquid  manure.  At  present,  however, 
we  can  only  say  that  the  three  leading  principles  of  manure  are, — 
1.  Ammonia  ; 
2.  Phosphorus  ; and  probably 
3.  Carbon. 
But  a word  may  be  said  as  to  the  preparation  of  these  two 
cardinal  elements,  phosphorus  and  ammonia.  Phosphorus  in 
bones  is  sluggish  and  does  not  go  to  work.  Ammonia  is  volatile 
and  flies  away.  Now,  to  quicken  phosphorus,  Liebig  has  taught 
us  to  dissolve  bones  with  sulphuric  acid;  a most  valuable  dis- 
covery. The  acid  is  applied  most  conveniently  to  bones  from 
which  the  gelatine  has  been  burnt  out,  which  is  generally,  I be- 
lieve, done  for  other  purposes;  though  bones  have  lately  arrived 
from  South  America,  ready  burnt,  for  the  convenience,  I suppose, 
of  carriage,  but  to  the  entire  waste  of  the  ammonia.  But  bones,  if 
piled  up  wet  in  mould,f  may  be  also  in  great  part  decomposed, 
and  their  action  accelerated.  This  process  is  also  in  strict  ac- 
cordance with  the  laws  of  chemistry  ; for  Liebig  says, — 
“ Bones  become  warm  when  reduced  to  a fine  powder;  and  moistened 
bones  generally  heat  and  enter  into  putrefaction  ; the  gelatine  is  decom- 
posed, and  its  nitrogen  is  converted  into  carbonate  of  ammonia  and  other 
ammoniacal  salts,  which  are  retained  in  a great  measure  by  the  powder 
itself.” 
If  mould  be  added,  as  I recommended,  the  ammonia  will  nearly 
all  be  retained,  and  goes  into  the  earth  in  readiness  for  the  next 
corn-crop.  I should  still  use  some  superphosphate,  because  it 
acts  quickest.  But  it  sometimes  seems  to  act  even  too  quickly, 
leaving  the  turnip  aground  in  the  midst  of  its  growth.  The  half- 
reduced  bones,  if  drilled  in  a mixture,  would  then  take  up  its 
work  and  finish  the  root. 
To  fix  ammonia  is  the  other  great  lesson  taught  by  Chemistry, 
and  gypsum  is  often  prescribed  as  the  means.  Ten  years  ago  I 
tried  gypsum  for  this  purpose,  but  unsuccessfully.  Ammonia 
was  escaping  largely  from  the  litter  of  a farmyard,  as  could  be 
perceived  by  the  common  test  of  holding  near  the  surface  paper 
dipped  in  spirits  of  salt,  which  turns  the  invisible  fugitive  into  a 
white  opaque  steam  of  sal-ammoniac.  A whole  bushel  of  gypsum 
was  strewed  over  a few  square  feet  of  the  yard.  The  test  showed 
that  the  escape  of  ammonia  was  uncured.  We  have  been  also 
advised  to  strew  the  pavement  of  stalls  with  gypsum  to  sweeten 
our  stables.  The  remedy  was  applied  in  my  own,  but  the  stables 
not  sweetened.  A caution  concerning  gypsum  was  therefore  in- 
* See  account  of  Swiss  Water-meadows,  in  the  present  Number, 
f Pusey,  On  a new  mode  of  preparing  Bones  for  Manure. 
