of Temperature in Connection with Elevation. 445 



1° or 2° to the upper stations. But, as a balance against this, 

 it is to be remarked, that ascents were commonly commenced 

 on fine mornings ; which, on some of the days, were followed 

 by cold and rainy afternoons. Ben Loyal, and the first ascent 

 of Ben Nevis, furnish examples of this; while on Ben Nevis, 

 the second day, Red Cairn, and the Locheil and Braemar 

 moors, the weather was warm and sunny. On Ben-na-muic- 

 Duich and Ben Hope, there was thick mist : on the former, 

 it was more dense towards the summit ; on the latter, it was 

 partially transparent to the sun's rays near the summit of the 

 hill, though very dense below. On the whole, I incline to 

 believe that these several sources of error would nearly coun- 

 terbalance each other. 



From a few similar observations in Cumberland, during 

 May and June of 1833, I obtained 298 ft. of ascent for a 

 decrease of 1° of temperature ; the weather being dry, warm, 

 and sunny. Other observations, in Caernarvonshire, in the 

 beginning of May, 1832, give only 212 ft. for 1° of tempera- 

 ture; the weather cold and humid. Otley's Guide to f he Lakes 

 mentions incidentally that the difference of temperature between 

 Keswick and the summit of Skiddaw is about 12°. This gives 

 230 ft. for 1° of temperature ; but the author informed me that 

 his average was only drawn from a few observations, not suf- 

 ficient for much confidence. The following is a summary of 

 these several conclusions : — 



The only place of considerable elevation, the mean annual 

 temperature of which has been determined with precision, is 

 that of Lead Hills in Lanarkshire, at 1280 ft. Comparing 

 the average temperature of it and of adjacent situations near 

 the sea level, we find a much slower decrease of temperature 

 tl\an the preceding observations would lead us to expect : — 

 Canaan Cottage gives 1° of temperature for 340 ft. 

 Carlisle - - - - 480 



Kendal - - - - 462 



Keswick - - - - 294 



Jesmond - . - - 400 



Mean 



- 395 ft. 



We can hardly doubt that the temperature of Lead Hills 

 is above the true average for its height. The observations 

 were made at 6 a.m. and 1 p.m. ; which hours, taken together, 



