Thomas Andrew Knight, Esq. 565 



period, in a situation to which sufficient water to turn a mill- 

 wheel one day in a month cannot now be obtained in the 

 latter part of the Summer and Autumn. Under these circum- 

 stances the ground must necessarily become much more dry 

 in the end of May than it could have been previously to its 

 having been enclosed and drained and cultivated; and it 

 must consequently absorb and retain much more of the warm 

 Summer rain (for but little usually flows off) than it did in 

 an uncultivated state; and as water in cooling is known to 

 give out much heat to surrounding bodies, much warmth 

 must be communicated to the ground, and this cannot fail to 

 affect the temperature of the following Autumn. The warm 

 Autumnal rains, in conjunction with those of the Summer, 

 must necessarily operate powerfully upon the temperature 

 of the succeeding Winter ; and, consistently with this hypo- 

 thesis, I have observed that during the last forty years, when 

 the weather of the Summer and Autumn has been very wet, 

 the succeeding Winter has been in the climate of this vici- 

 nity generally mild. And that when north-east winds have 

 prevailed after such wet seasons the weather in the Winter 

 has been cold and cloudy, but without severe frost, probably 

 in part owing to the ground upon the opposite shores of the 

 Continent being in a state similar to that on this side the 

 Channel. 



I was first led to notice the preceding effects by having 

 observed, many years ago, that some trees of the common 

 Laurel, which grew in a very high and cold situation, and 

 which usually lost a very large portion of the annual wood, in 

 more than one Winter totally escaped all injury after such 

 wet seasons, though their annual wood did not appear more 



