of Temper ahire in Connection mill Elevation. 447 



heights at which they burst from the mountain were from 

 2700 ft. to 3247 ft. At the end of April, the temperature of 

 drain-springs at lower elevations in the adjacent hills was : — 



In Otley's Guide to the LaJces it is stated, that, '•' on the 

 sloping side of Helvellyn, about the distance of 300 yards, 

 and 300 perpendicular feet below the summit, is a spring, 

 called Brown-rigg Well, where the water issues, in all seasons, 

 in a copious stream ; its temperature in the summer months 

 being from 40° to 42°." The height of this spring must be 

 about 2750 ft. In May of 1833, I found the temperature of 

 a feeble spring (in very hot weather), at about 350 ft. of ele- 

 vation, to be 49 J° of a thermometer graduated by Ronchetti 

 of Manchester; and of a spring-drain, at 450 ft., the tempe- 

 rature v/as 53° : but as this thermometer stands 2J° above 

 thermometers obtained from Adie, the temperatures may be 

 called 47° and 51^°. 



Now, using these very imperfect data, we get the results 

 given below, towards ascertaining the decrease of temperature 

 in the earth as we ascend above the sea level. 



I have before assumed the decrease of atmospheric tem- 

 perature to be 1° for 240 ft. of ascent. Let us compare this 

 with 380 ft., as the rate of decrease of temperature in the 

 earth ; and we then have, as the assumed temperature of the 

 earth and atmosphere on the Grampians : — 



