816 Mr. Thomas Gushing on 



92. — Wandle Temperatures. 



By Thomas Gushing, F.E. Met. S. 



(Read February 11th, 1891.) 



The question of the variations found in the temperature of the 

 River Wandle is one which, I think, ought to have some interest 

 for us, as it is of a purely local character ; and it is on this 

 account that I venture to draw attention to the great discrepancies 

 which occur within a very limited area of this river, and will, 

 with your permission, say a few words this evening by way of 

 supplementing the Meteorological Sub-Committee's Report, which 

 has just been read to us. 



The observations from which my analysis has been made were 

 taken every Sunday afternoon throughout the year 1889, by our 

 indefatigable Hon. Secretary, Mr. Bayard, and the way in which 

 he has tabulated the observations and worked out the means — if 

 he will allow me to say so — does him the greatest possible credit. 

 I believe he has taken them both before and after this period, but 

 1889 is the only complete year with which I have had the oppor- 

 tunity of dealing. I understand that all the observations were 

 taken with the same thermometer, that the thermometer is 

 graduated on the stem, and has been verified at Kew. The 

 depths at which the observations were taken vary from 12 to 18 

 inches below the surface of the water. 



In all there are ten stations on this river, within an area of one 

 mile, five on the Garshalton branch and five on the Croydon 

 branch. The Garshalton stations are at Park Wall, Phillpott's 

 Corner and Haydon's Corner, at the Lower Pond steps, at the 

 Upper Pond, Old Rectory Stream, and at Waterhouse Pool. 

 And, on the Croydon branch, at the Road Well, Walhngton Old 

 Manor House, the mill-stream and pool-stream at Smee's Mill, 

 and the road-stream and pool-stream at Wallington Manor House. 

 Those are the stations at which the temperatures were syste- 

 matically taken every Sunday throughout 1889. 



The stations are numbered from 1 to 5 on the Garshalton 

 branch, and from 6 to 10 on the Croydon branch. 



1889. 

 Temperatures. — Carshalton Branch of Wandle. 



Greatest difference. 

 Station 1. Lowest, 37-7°. Dec. 29. 



Highest, 58-3°. Aug. 4. 20-6° Fahr. 



2. Lowest, 45-1°. Dec. 15. 

 Highesf 54-9'^ Sept. 1. 9-8' 



3. Lowest, 49-9°. Dec. 30. 

 Highest, 51-6°. Aug. 4. 1-7° 



