CLIxMATE. 29 



These accord very nearly with the preceding observ- 

 ations on the temperature of the air. The means for 

 places between the parallels of 53 — 56° (Helvellyn and 

 Lead Hills excluded) is 47-J ; or one fourth of a degree 

 below the mean temperature of the air. The warmer 

 spring at Barnstaple forms a pump-well, and the tem- 

 perature of the water was taken weekly after pumping 

 until the water raised came to a settled temperature. The 

 extremes observed were 49 and 56. From July to Oc- 

 tober, 1833, observations were made by the present 

 writer; from October 1833 to June 1835, they were 

 made by his sister, Mrs. Wakefield, on whose accuracy 

 he can rely. The calculation is made for 1834; the 

 records in months of the preceding and succeeding year 

 coincide very nearly. The colder spring gushed copiously 

 from a limestone rock at Landkey, near Barnstaple, and 

 tried from July to October, 1833, did not vary a quarter 

 of a degree. The temperature at Ditton is that of a 

 pump-well, tried monthly during 1834. The extremes 

 were 47 J and 61. This well is near the surface, partly 

 under the floor of a house, and only six yards horizontally 

 from a kitchen fire ; the temperature is obviously raised 

 too high. 



According to data given in the Magazine of Natural 

 History before referred to, there is a decrease of tem- 

 perature in the earth, within Britain, equal to 1° of Fah- 

 renheit's scale for 125 — 127 yards ; the former being the 

 mean of the year between latitude 54 — 56° ; the latter, 

 of the spring and summer months between 53 — 57°. 

 Taking 125 yards, and assuming the temperature of the. 

 earth to be 48° at the sea level, we have the following 

 scale of presumed temperature in ascending the hills. But 

 in the south of England and north of Scotland a higher 

 and lower temperature must be taken for the sea level. 



c 3 



