CLIMATES OP GREAT MALVERN AND LONDON. 65 



The higher mean denoted in the above result, arises probably from 

 the mildness of the winter of 1834 and 35. Humboldt reckons the 

 mean temperature of winter in London at 39.6°, whereas, from the 

 foregoing data, it was 41''. Daniell makes it only 38°. 



I have, on three several occasions, tried the temperature of a very 

 fine, deep, and copious spring in the village of Great Malvern, and 

 with the following results. In the first, temp, of the air 30° ; ther- 

 mometer, immersed to the bottom of the spring, 50°. In the second, 

 temp, of the air 56°, of the spring 50.5*^. In the third trial, during 

 very hot and dry weather, the temperature of the air was ']5^, and 

 the water 52^.* 



ATMOSPHERIC PRESSURE. 



1. — The fluctuations of the barometer at London and Great Mal- 

 vern are very nearly simultaneous, and the daily range is, 

 also, very nearly the same. 



2. — The mean range for the seasons was — - 



In London. In Malvern. 



Summer 687in. Summer 727in. 



Autumn 1.255in. Autumn 1.242in. 



Winter 1.442in. Winter 1 .527in. 



Spring 1.122in. Spring 1.123in. 



* The temperature due to any given elevation may be found as follows 



Reckoning the density of the air at the surface of a sphere as unit, the dif- 

 ference between the density of any given altitude and its reciprocal being 

 multiplied by 45, will express the mean diminution of temperature in de- 

 grees of Fahrenheit's scale. Now the difterence of density of the air at 

 Malvern and London is .574 in. nearly, as shewn by the barometer. 



Therefore 



30.000 : 29,426 : : 1.000 : .980 

 which is the density of the air of Malvern, the density at London being 1. 



Therefore 



,980 : 1.000 : : 1.000 : 1.020 and 

 1.020 ^ ,980 = ,040 X 45 = 1.8° 



the diminution of temperature due to the elevation of Malvern. It has just 

 been stated that Mr. Daniell makes the mean temperature of London, accord- 

 ing to his observations, 49.5 : and this agrees to the decimal place with Mr. 

 Howard's estimate. Humboldt states the mean temperature of London at 

 50.4; so that 52° is, doubtless, rather high. 



Now, considering the mean temperature of Malvern as 49.6, and adding to 

 it 1.8° the diminution due to elevation, the result is 51.4°. We conclude, 

 therefore, that there are no peculiar causes tending to depress the thermome- 

 ter in that locality. 



October, 1835. — vol. hi. no. xiii. f. 



