10 Dv Davy's Meteorological Observations. 



the mild rain were 48° ; whilst the Rotha, which, during the 

 frost, we have seen, was many degrees higher than them, 

 was now lower, vai'ying in temperature from 40° to 45", ac- 

 cording to its distance from the lakes out of which it flowed. 

 This is a subject to which I may recur. 



I have mentioned in describing the ground-ice, the effect 

 of a little warm stream, brought by a deep drain into Scan- 

 dale-gill, preventing the formation of this ice. Is not this 

 effect interesting and worthy of attention, as tending to 

 illustrate how draining, at the same time that it increases 

 the fertility of land, promotes its wai'mth, and that of the 

 incumbent air and its dryness, wai^ming, too, the river 

 which it feeds, and that in a graduated manner, as from a 

 reservoir ? I may add a few thermometrical observations in 

 confirmation. On the 13th of March, when the little stream 

 mentioned was 42°, another flowing from an ill-di'ained field, 

 partly marshy, was 35° ; and whilst the marshy part of this 

 field was frozen, the dry grass, at its roots, in the well- 

 drained field, was 35° ; the air at the time being 33\ And, 

 besides the cold occasioned by a surface of ice, it should be 

 remembered, that even after the ice has disappeared, the 

 stagnant water, in the act of evaporating, will have on the 

 gi'ound, and on the atmosphere, a cooling influence. 



3. Another phenomenon somewhat akin to ground-ice, viz., 

 icicles from the projecting ledges of rocks, and sheets of ice 

 on their slopes, as it were miniature glaciers, are, as might 

 be expected, of common occurrence in these valleys, present- 

 ing often a very beautiful appearance. I need hardly ob- 

 serve, that their production is intimately connected with the 

 circumstances favouring radiation, especially the clear sky, 

 with thawing in the sunshine, and freezing in the shade. 



That these valleys wei'e once the site of enormous glaciers, 

 almost comparable with any now existing amongst the Alps, 

 is strongly indicated, by the worn rounded surfaces of the 

 lower hills and rocks ; by the well-marked grooves and 

 scratches on the latter ; by accumulations of debris, resem- 

 bling moraines; and by great moved masses of rock, in situa- 

 tions where they could hardly have fallen, having the cha- 

 racter of erratic masses, and in many instances marked like 



