IV. CLIMATE. IGl 



j'arcls of ascent. If an allowance be made for the dif- 

 ference of latitude between Lead-hills and Colinton, these 

 figures will be reduced. 



In Otley's Guide to the Lakes, it is mentioned that 

 Brownrigg Well, a spring at the height of 2750 feet on 

 Helvellju, a few miles from Keswick in Cumberland, has 

 a temperature of 40 to 42 in the summer months. The 

 annual average of a spring or springs near Keswick, at 

 250 feet of height, is stated to be 462^. In comparing the 

 temperatures of these two altitudes, the lowest summer 

 temperature of Brownrigg Well must be taken ; and even 

 that may be too high for an annual average. The dif- 

 ference of 62- of temperature for 2500 feet of altitude, 

 gives a rate of 385 feet or 128 yards for one degree of 

 temperature in Cumberland. Coupling this rate of de- 

 crease with that for Colinton and Lead-hills, we obtain a 

 mean of 332 feet or 110 yards for one degree of tempera- 

 ture. Or, making a direct comparison between Brown- 

 rigg Well at 40, and Lead-hills at 44, the difference of 

 height is 1470 feet for 4 degrees of temperature ; to which 

 half a degree of Fahi'enheit ought to be added for dif- 

 ference of latitude ; giving a rate of 326 feet of ascent for 

 one degree of temperature. 



In August, 1832, the small spring well near the top of 

 Ben Nevis, say at 3800 feet, had the temperature of 39. 

 A more copious spring at the height of 2200 feet, gushing 

 out on the moor above Loch Eil, some few miles from 

 the well on Ben Nevis, had the temperature of 43, at the 

 same date. This gives a rate of 400 feet for one degree 

 of temperature. But very probably the temperature of 

 the small spring on Ben Nevis was more raised in pro- 

 portion to its altitude, than was the copious spring on the 

 lower moors, at that season of the year. Indeed, in July 



VOL. IV. Y 



