648 
Report  on  Wheat- Mildew. 
was  much  less  conspicuous  than  in  1852  or  1881.  In  the  last- 
named  year  we  had,  from  the  3rd  of  July  to  the  5th,  warm  days, 
the  last  of  these  days  being  remarkably  hot ; on  the  night  of 
the  5th  we  had  a thunder-storm  with  heavy  rain,  and  the  tem- 
perature dropped  at  Cambridge  from  89°  in  the  shade  in  the  day- 
on  the  5th,  to  46°  at  night  on  the  6th.*  On  the  16th,  mildew 
was  observed  on  some  cottage  allotments  in  this  parish  ; and  on 
the  18th,  as  1 have  stated  previously,  1 found  it  everywhere  on 
my  farm.  Now  I believe  that  11  days  are  supposed  to  be 
about  the  time  that  it  takes  for  the  development  of  the  disease 
after  it  has  entered  the  wheat-plant ; and  there  can  be  little 
doubt  that  the  mischief  was  done  in  the  course  of  a few  hours  on 
the  5th,  6th,  or  7th  of  the  month. 
6.  Soil:  7.  Previous  Cultivation. — It  will,  I think,  be  con- 
venient to  consider  the  influence  of  soil,  cultivation,  and  manur- 
ing under  one  heading,  as  it  is  not  necessary  for  the  purposes  of 
our  inquiry  to  distinguish  between  the  natural  and  acquired  fer- 
tility of  the  land  ; between  the  “ inherent  capabilities  ” of  the  soil 
and  that  “ condition”  which  may  be  the  result  of  good  manage- 
ment. Probably  there  is  no  point  in  connection  with  mildew  on 
which  farmers  would  be  found  so  unanimous  in  opinion  as  that 
(1)  certain  descriptions  of  soil  are,  in  the  districts  which  have 
come  under  their  observation,  more  liable  to  attacks  of  this 
disease  than  others  ; or  (2)  that  a particular  course  of  hus- 
bandry, or  a particular  application  of  manures,  does  promote  the 
disease.  It  will  be  worth  while,  then,  to  inquire  whether  there 
is  any  general  agreement  as  to  the  description  of  soil,  the  pre- 
vious crop,  and  the  system  of  manuring  which  is  believed  to 
develop  bad  attacks  of  mildew,  and  if  so,  to  proceed  to  inquire 
whether  the  opinion  has  any  scientific  basis. 
Soils. — And  first  as  to  soil.  In  the  fen  country,  which  I have 
so  often  named  as  very  subject  to  mildew,  there  are  four  different 
classes  of  soil,  known  locally  as  (1)  strong,  (2)  silt,  (3)  skirt, 
(4)  black  fen.  Of  course,  this  classification  is  only  a rough  one. 
Some  fields  contain  a mixture  of  two  or  three  classes,  and  there 
are  many  gradations  of  texture  and  tenacity.  The  “ strong 
land  ” is  an  alluvial  clay,  which  does  not  compare  in  its  stiffness 
with  the  soil  of  some  of  the  Midland  counties,  but  it  is  adhesive 
enough,  and  difficult  to  work  in  wet  seasons.  The  “ silt  ” has  a 
considerable  proportion  of  soft  and  fine  sand  ; it  is  easily  worked, 
and  retains  moisture.  The  “ skirt  ” land  is  a mixture  of  the 
peat  fen  soil,  with  alluvial  clay  and  silt  deposited  by  the  tide. 
The  fen  land  is,  in  its  original  state,  almost  entirely  vegetable 
mould  or  peat,  but  the  character  of  it  has  been  almost  univer- 
* ‘ Meteorologica’  Office  Daily  Weather  Reports.’ 
