§30 The Northern Expeditions. 



The following are mean temperatures observed at Kinfauns 

 Castle : — 



1814 1815 1816 1817 



Annual mean. 43-4'^ 46° 427° 44-26" 



This is also fatal to the icy theory; for in 1814 we have no 

 particular record of frozen islands; yet its temperature was lower 

 than those of 1815 and 1817, when they are said to have abounded. 



Again, the position of Mr. Barrow on which his argument prin- 

 cipally rests, that " during the last two summers the mercury in- 

 variably fell with westerly winds," is wholly contrary to the fact; 

 as may be seen from the following result of Mr. Howard's obser- 

 vations at Tottenham: — 



18 16, April to Sept. ^'^^fy "^ iresterly ^oind^_ 

 both inclusive. 52 days 53-6" 101 days 54-57° 



1817. Do. 61 53-27° 95 55-23° 

 The attempt, therefore, to explain the weather by the ice-bergs 



fails in every point. 



The facts not merely jar with Mr. Barrow's view, but are in 

 direct opposition to it; and the slightest examination of his ge- 

 neral principles is equally unfavourable to his conclusions, it is 

 not conceivable that our west wind, merely by passing over the 

 ice near Newfoundland, would be materially chilled in its gene- 

 ral volume; nor, if it were, is it reasonable to suppose that the 

 coolness would not afterwards be removed by the passage of the 

 wind over 500 leagues of open sea. In the close vicinity of the 

 ice, the air will indeed be sensibly chilled; and this effect is un- 

 happily experienced by the eastern states of America^ where the 

 north-east wind is extremely injurious: but the case is entirely 

 changed when the broad bosom of the ocean presents the warmth 

 of the latitude of 50° to repair the partial diminution of tempe- 

 rature. 



The real cause of the coldness of 1816 and 181 7 "'as undoubt- 

 edly the wet and cloudy weather that almost constantly prevailed 

 in summer. Rain is yet without a theory; but it seems pretty 

 certain that it is governed by other circumstances than those 

 which occur on the surface of the globe; and it is probable that 

 the unequal distribution of electricity is the principal source of 

 diversified seasons. If the theorv of the Journal of the Royal Irt- 

 s-titution was authentic, we should have had less rain during the 

 last two years than usual ; inasmuch as the wind, being con- 

 densed by the ice-bergs, would lose a proportional share of its 

 moisture. 



What has been advanced respecting the vineyards and orchards, 

 of Great Britain, is nonsense too pure for controversy. 



Philosophy is never useful but when her general reasonings are 

 applied to special cases : but this is not done without hazard ; 



since 



