12 
On  the  Climate  of  the  British  Islands 
But  the  soil  of  these  islands  receives  a much  greater  amount, 
Dalton’s  estimate  of  the  average  annual  quantity  for  England  being 
3 1 '3  inches.  More  recent  observations  on  elevated  land  have  shown 
that  the  western  mountainous  districts  are  drenched  with  enormous 
quantities  of  rain,  equal  to  some  of  the  wet  regions  within  the 
tropics.*  This  appears  to  arise  from  the  following  combination 
of  causes : — 
31.  The  waters  of  the  Gulf  of  Mexico,  augmented  by  the 
equatorial  current,  confined  for  a season  as  in  a caldron,  are  heated 
under  a tropical  sun  to  a temperature  of  86°.  The  Gulf-stream 
carries  this  warm  water  northward  and  eastward  into  the  middle 
of  the  Atlantic,  where  it  is  spread  over  an  area  at  least  equal  to 
four  times  the  extent  of  France.  A more  than  ordinary  eva- 
poration arises  from  this  part  of  the  ocean  ; the  prevailing  south- 
west wind,  after  sweeping  this  part  of  the  Atlantic,  arrives  at  our 
western  shores  laden  with  moisture  ; the  colder  air  of  the  mountain 
districts  condenses  the  vapour,  and  the  result  is — an  abundance  of 
rain. 
32.  The  following  table  has  been  collected  from  the  authorities 
therein  mentioned,  and  is  so  arranged  with  regard  to  the  latitude 
of  the  places  named,  that  the  eye  can  trace  in  order  the  annual 
amount  of  rain  which  falls  on  the  western  and  eastern  sides  of 
Great  Britain. 
Table  IV. — Showing  the  Annual  Fall  of  Rain  at  the  places  mentioned. 
Places. 
Mean  of  Y^ars. 
Height 
in  Feet. 
Rain  in 
Inches. 
Authorities. 
The  Western  Coast,  and 
ELEVATED  LANDS  : 
Sandwich,  Orkney  . . 
{ 1842tol84s} 
36-8 
Phil.  Mag. 
Dunoon  .... 
• • 
56- 
Milner. 
Greenock  . . 
• • 
40* 
Ditto. 
Glasgow  .... 
30 
30- 
M‘Culloch. 
Carbeth,  Stirling 
8 
42-5 
Ditto. 
Mount  Stewart,  Bute 
7 
46-6 
Ditto. 
Applegarth  Manse  . 
|l839tol84s} 
33-6 
Phil.  Mag. 
Cockermouth  . . 
4 
48-5 
Trans,  of  Royal  Soc. 
Whitehaven  . . . 
4 
47-1 
Ditto. 
Keswick  .... 
4 
258 
63-6 
Ditto. 
Gatesgarth  . . 
4 
326 
121-4 
Ditto. 
Seatliwaite  . 
4 
• • 
146-4 
Ditto. 
Kendal  .... 
4 
• • 
58- 
Journal  of  Science. 
Isle  of  Man  . . 
5 
• . 
36-2 
Ditto. 
Liverpool  . . . 
• • 
• • 
34-1 
Prout,  Bridgewater  Treatise. 
Bolton  .... 
4 
320 
44'  1 
Report  on  Supply  of  Water 
Rochdale  . . 
4 
500 
47*5/ 
to  Manchester. 
Manchester  . . 
• • 
• • 
36-1 
Prout,  Bridgewater  Treatise. 
* Seatliwaite,  Westmoreland — av.  4 yrs. — 146  inches;  St.  Domingo,  120  inches  ; 
Grenada,  112  inches. 
