36 
On  the  Climate  of  the  British  Islands 
character,  when  no  rain  fell  for  four  succeeding  months ; but 
even  then,  though  the  straw  was  remarkably  scanty  in  the 
eastern  districts,  the  ear  was  crowded  with  grain.  In  the  south- 
western counties  the  crop  was  of  the  most  abundant  description  ; 
and  I well  remember  the  feeling  of  astonishment  with  which,  on 
my  father’s  farm,  I viewed  this  crop  with  several  friends,  gather- 
ing the  finest  ears,  and  observing  that  five  grains  in  a row  on 
each  side  was  almost  universal — to  use  a common  phrase,  “ it 
was  kerned  like  peas.” 
79.  The  most  important  inference  from  this  table  is,  that  the 
summer  temperature  of  these  islands  is,  as  a whole,  within  a 
very  few  degrees  of  the  minimum  temperature  required  for  the 
perfection  of  wheat;  a deficiency  of  2°  or  3J  places  the  whole 
crop  in  the  utmost  jeopardy  ; almost  invariably  there  results  a 
great  falling  off  in  quantity  and  quality,  which  is  most  severely 
felt  in  Scotland,  the  north  of  Ireland,  and  in  the  west  of  Eng- 
land. 
80.  By  consulting  the  tables  in  the  c Philosophical  Transac- 
tions of  the  Royal  Society’  for  1849,  arranged  by  Mr.  Glaisher, 
especially  Tables  3 and  7,  it  will  appear  that  a succession  of 
warm  and  cold  summers  occur  in  groups.  The  sign  of  plus(  + ), 
by  which  the  excess  of  heat  is  indicated,  is  distributed  over  the 
page  like  clusters  of  stars.  Yet,  after  a careful  investigation, 
I cannot  succeed  in  tracing  any  cycle  of  returning  warm  and 
cold  seasons.  Three  or  four  warm  summers  are  generally  fol- 
lowed by  a variable  number  of  cold  ones.  Previously  to  the 
great  heat  of  1818,  there  was  for  nine  years  a succession  of  re- 
markably cool  summers.  These  Tables  appear  to  destroy  the 
expectation  of  any  definite  cycle  of  returning  seasons  being 
established,  on  which  any  practical  reliance  can  be  placed.  It  is, 
however,  an  important  admonitory  fact,  that  an  unfavourable 
summer  seldom  appears  alone. 
81.  It  is  further  observable  that  the  character  of  the  spring  is 
generally  extended  to  the  summer,  a cold  spring  being  followed 
by  a cold  summer.  There  are,  however,  many  exceptions  to  this 
rule,  but  a late  precarious  harvest  may  be  anticipated,  if  the  early 
months  of  the  vegetative  season  are  cold  and  ungenial,  and  the 
husbandman  will  do  well  to  prepare  to  make  every  exertion  to 
ward  off  the  effects  of  such  a calamity.  I proceed  to  ascertain — ■ 
82.  The  amount  of  Heat  necessary  for  the  perfection  of  Wheat, 
in  these  Islands. — Linder  this  head  1 shall  not  follow  the  intricate 
course  adopted  by  Boussingault,  of  determining  the  amount  of 
atmospheric  and  solar  heat  requisite  from  the  first  growth  of  the 
plant  in  spring  to  the  perfection  of  the  grain. * This  elaborate 
* Journal  of  Royal  Agricultural  Society. 
