424  “ Fertilisers  and  Manures”  hy  A.  D.  Hall. 
that  the  future  lies  with  intensive  farming,  and  that  as  science 
every  year  puts  fresh  weapons  in  the  hands  of  the  farmer  it  is 
essential  that  he  should  have  skill  and  knowledge  in  wielding 
them.  The  author’s  ideal  is  to  teach  the  farmer  to  reason  out 
for  himself  the  scheme  of  manuring  best  suited  to  his  soil  and 
style  of  farming,  by  explaining  the  mode  of  action  of  the  various 
manures,  and  their  relation  to  different  crops  and  soils.  He  is 
especially  to  be  commended  in  our  opinion  for  insisting  that 
there  is  no  universal  best  way  of  manuring,  and  that  the 
proper  business  of  the  expert  is  to  lay  down,  as  far  as  he  can, 
principles  which  the  practical  man  must  learn  to  apply  to  his 
own  conditions.  The  style  of  the  book  throughout  is  lucid  and 
non-technical,  and  no  space  is  wasted  on  details  of  the  methods 
of  manufacture  of  fertilisers,  matter  which  possesses  no  interest 
for  the  practical  man. 
After  an  introduction,  which  is  mainly  historical,  Mr.  Hall 
devotes  a number  of  chapters  to  nitrogenous  manures,  phosphatic 
and  potassic  fertilisers,  farmyard  manure,  guanos,  and  theories  of 
fertiliser  action.  We  found  the  last-mentioned  chapter  very 
interesting,  particularly  the  criticism  of  the  American  doctrines 
as  to  the  uselessness  of  fertilisers  as  direct  plant-foods.  Though 
the  author  cannot  bring  himself  to  agree  with  the  heretical 
views  of  the  American  school,  nevertheless  we  feel  that,  in  view 
of  his  recent  researches  on  the  infusorial  population  of  the  soil, 
and  his  advocacy  of  soil  surveys,  he  would  be  the  first  to  admit 
that  a purely  chemical  view  of  the  action  of  fertilisers  is 
insufficient  to  explain  all  the  beneficial  efffects  that  follow  their 
use.  Another  criticism  we  would  offer,  with  extreme  diffidence, 
is  in  relation  to  the  vexed  question  of  residual  values.  If  it  be 
true,  as  stated  on  page  205,  that  though  the  superiority  of  cake- 
fed  dung  may  be  seen  in  the  second  or  third  year  it  is  almost 
covered  by  the  experimental  error,  why  do  the  tables  prepared 
by  the  author,  in  collaboration  with  Dr.  Voelcker,  give  a 
residual  value  to  cake  up  to  the  third  and  fourth  year  ? 
The  chapters  that  follow  on  the  manurial  treatment 
appropriate  to  the  principal  farm  crops  are  those  in  which  the 
farmer  will  find  the  most  interesting  matter,  for  they  are  largely 
based  on  the  result  of  field  experiments,  and  are  consequently 
independent  of  theory  ; they  are  especially  illuminating  in  the 
emphasis  they  give  to  the  variations  that  the  system  of  farming 
in  operation  necessitates  in  the  scheme  of  manuring.  Every 
farmer  should  become  thoroughly  conversant  with  the  principles 
and  methods  laid  down  in  the  chapter  on  the  valuation  and 
purchase  of  manures  ; if  the  lessons  they  convey  should  have 
the  effect  of  diminishing  the  credit  of  proprietary  “special 
mixtures,”  a great  advance  in  agricultural  education  will  have 
been  made. 
