24 
On  the  Climate  of  the  British  Islands 
by  night  was  scarcely  perceptible,  an  occasional  variation  of  1 1° 
might  be  observed  ; but  on  the  tidal-water  of  the  Fal,  twelve 
miles  from  the  sea,  I found  the  difference  on  clear  days  to  be  from 
2°  to  4°. 
It  is  known  that  the  sea-water  becomes  colder  on  nearing;  the 
land,*  deep  water  being  the  warmest  at  the  surface  ; and  the 
thermometer  showed  at  St.  Agnes  a somewhat  higher  temperature 
on  a flowing  tide  than  on  the  ebb.  The  full  effect,  therefore,  of 
the  Atlantic  on  the  climate  of  the  western  coast  is  somewhat 
greater  than  these  observations  indicate. 
59.  The  Transactions  of  the  Royal  Society  for  1849,  part  ii., 
contain  the  thermometrical  observations  made  at  the  apartments 
of  the  Society  from  1774  to  1843,  reduced  and  arranged  by  Mr. 
Glaisher.  From  Table  III.  it  appears  that  great  variations  have 
taken  place  in  the  January  mean  temperature  : in  1795  it  was 
below  the  average  11  *7 ; on  the  following  year  it  was  in  excess 
9°*  7 ; making  a difference  of  2L*4.  These  extraordinary  winters 
were  followed  by  a great  diminution  of  heat  in  July,  with  defective 
harvests ; and  corn  rose  to  very  high  prices.  The  following  table 
gives  a condensed  view  of  these  interesting  facts  : — 
Year. 
January : 
Variations 
from 
Mean. 
July  : 
Variations 
from 
Mean. 
Price  of 
Corn  per 
Quarter.f 
1794 
o 
- 2-3 
o 
+ 3-9 
s.  d. 
52  3 
1795 
-11*7 
-2-5 
75  2 
Very  bad  crop  of  wheat — a year  of  dearth. 
1796 
+ 9-7 
-2-8 
78  7 
Many  of  the  poor  died  of  want. 
1797 
+ 0*2 
+ 1*9 
53  9 
Captain  Sabine,  in  a voyage  to  Madeira  in  January,  1822, 
found  an  excess  of  temperature  in  the  water  of  the  Atlantic  of 
from  3d  to  6°;  and  he  attributes  to  this  fact  the  peculiar  mild 
character  of  that  winter.  Mr.  Daniell,  in  his  1 Essay  on  the 
Climate  of  London,’  says,  “ November,  1821,  differed  from  the 
mean  and  from  both  the  preceding  years  in  a very  extraordinary 
way.  The  average  temperature  was  5°  above  the  usual  amount; 
the  quantity  of  rain  exceeded  the  mean  by  one-lialf:  all  the  low- 
lands were  flooded,  and  the  sowing  of  wheat  was  very  much  in- 
terrupted by  the  wet. — In  December  the  mild  temperature  pushed 
forward  all  the  early  sown  wheats  to  a height  and  luxuriance 
scarcely  ever  before  witnessed.  The  grass  and  every  green  pro- 
duction increased  in  equal  proportion. — January,  1822.  This 
* Phil.  Mag.,  vol.  lxvii.  p.  339.  f Pari.  Return,  March  23,  1843. 
