27 
The following figures show the temperature of the 
ground on the 3rd February, 1881, as taken at the 
Author’s house at Croydon: * 
Max. Min. | 2-5fect. | 5feet. | 10 fect. | 15 feet. 20 feet, 
6 ins. 6 ins. 
°. ° ° ° ° : ° Ate 
41:0 29°0 38°2 39°5 45°1 ATT 49:9 
25 feet. 30 feet. 35 feet. 40 feet. 45 feet. 50 feet. 
° ° ° ° ° ° 
50°3 50°5 50°3 50°10 50:0 50°10 
With reference to the first two temperatures, six 
inches maximum and six inches minimum, these are 
Temperature 
of the ground. 
registered temperatures and give the highest and ,- 
lowest temperatures recorded ; the other temperatures 
are daily temperatures taken at 9 A.M. in the day. It 
will therefore be seen, by comparing the temperatures 
above.ten feet with the temperature of the Bourne 
where it flows above the surface, that the ground 
temperature will account for the particularly low 
temperatures observed in these Bourne flows as com- 
pared with the temperatures of the water flowing from 
Oxted Tunnel and in the wells of the Kenley and 
Croydon Waterworks. 
Another peculiarity has been observed in the Bourne, 
to which the Author, in 1881, directed attention in a 
paper read to the British Association at York, entitled 
“Influence of Barometric Pressure on the Discharge of 
Water trom Springs,” where it is pointed out that: 
* Mean temperature of the air for the year 1880 at the Author’s 
house at Croydon 49°84° Fahrenheit. 
Bourne flows 
influenced by 
barometric 
pressure, 
