636 
Climate  of  the  British  Islands 
1. 
Evaporation  from  a 
Surface  of  Water. 
Rain. 
West. 
2. 
East. 
3. 
West. 
4. 
East. 
5. 
Inches. 
Inches. 
Inches. 
Inches. 
January 
0-4 
0-6 
3-5 
1-5 
February 
0-9 
1-2 
3-0 
1-3 
March  . 
1-5 
1 • 9 
1-8 
M 
April  . 
•2-0 
2-4 
2-2 
1-3 
May 
3-1 
3-8 
2-4 
1-6 
June 
3-4 
4-2 
2-5 
1-7 
July  . 
3-0 
3-6 
4-1 
2-4 
August 
2-7 
3-4 
4-5 
2-0 
September 
2*2 
2-6 
4-0 
2-1 
October 
1-3 
1-6 
4-1 
2-0 
November 
0-6 
0-8 
3-7 
2-1 
December 
• 
0-4 
0-6 
3-9 
1-7 
Total  for  the 
Year 
21-5 
26-7 
39*7 
20-8 
It  appears  evident  from  the  preceding  table,  that  the  greatest 
quantity  of  rain  falls  where  there  is  the  least  evaporation  ; as  in 
fact  is  certain,  when  the  laws  which  have  before  been  stated  re- 
specting the  formation  of  vapour  in  the  air  are  taken  into  account. 
It  also  appears  that  in  months  whose  mean  temperatures  are  nearly 
equal,  viz.,  December  and  February,  November  and  March, 
October  and  April,  &c.,  there  is  nearly  double  the  evaporation 
from  water  in  the  spring  months,  and  nearly  double  the  quantity 
of  rain  in  the  autumnal.  It  also  appears  that  the  quantity  of  rain  in 
the  west  is  nearly  double  that  in  the  east ; and  the  cloudiness  of  the 
atmosphere  may  be  inferred  to  be  pretty  nearly  in  the  same  ratio, 
though  not  quite  to  so  great  an  extent.  It  may  also  be  inferred 
to  follow  partly  the  same  law  as  the  evaporation,  but  in  an  inverse 
order,  and  the  mean  state  of  the  general  cloudiness  of  the  air 
may  be  between  the  two,  and  it  may  be  properly  considered  to  be 
about  as  three  to  two,  or  the  cloudiness  of  the  western  part  may 
be  to  the  cloudiness  of  the  eastern  as  three  to  two. 
But  it  may  be  objected  to  this,  that  it  is  an  indirect  way  of 
reasoning  to  show  what  might  be  directly  proved  by  observation. 
In  reply  to  this,  I may  remark  that  many  persons  have  noted 
observations  of  the  state  of  the  atmosphere  with  respect  to  its 
cloudiness  or  clearness;  but  when  the  ever-changing  and  eva- 
nescent nature  of  clouds  is  considered — when  it  is  also  known  that 
the  same  clouds  assume  such  different  appearances  to  observers  at 
but  a small  distance  from  each  other,  so  that  a cloud  that  to  one 
person  may  appear  to  obscure  the  whole  heavens,  may  to  another 
appear  to  hide  but  a very  small  part  of  it — observations  will  be 
seen  to  be  subject  to  many  disadvantages. 
