78 Mr. H. S. Eaton, 



610 feet above sea-level ; but the thermometers were read only 

 to whole degrees, and the minimum thermometer was liable to 

 get out of order ; the results must therefore be accepted with 

 some reservation. 



In regard to the positions of the stations, Park Hill, Addis- 

 combe, and South Norwood are practically on the boundary 

 separating the drainage areas of the Waudle and Graveuey fi-om 

 the Kavensbourne. Park Hill station is near the top of the hill, 

 and both it and Addiscombe have a northern exposure, the 

 inclination of the ground at the former being the greater. 

 South Norwood is on a slope facing S.S.W., near the bottom of 

 Norwood Hill. Waddon, Wallington and Beddington are in 

 the Wandle Valley. Waddon is on a knoU surrounded on all 

 sides by slightly lower ground. The situation is a very open 

 one on the eastern slope of the knoll. Wallington is on ground 

 declining to the north. Beddington is on level ground, with 

 Mitcham Common not far oflf to the north-west, and the 

 Irrigation Farm to the west and south-west. The above are all 

 included within an area measuring 4 miles from north-east to 

 south-west — South Norwood to Wallington — by 2h miles from 

 south-east to north-west — Park Hill Eise to Beddington Lane, 

 and the town of Croydon lies within this area on the eastern side 

 of it. These stations are hereafter referred to as the Croydon 

 stations. West Norwood is 4 miles north of Croydon, in the 

 drainage area of the Effra, and is by so much nearer London. 

 The Eoyal Observatory, Greenwich, is on a promontory jutting 

 out from the table-land in the Park, the ground falling away 

 quickly to the north and north-west. The Kew Observatory is 

 in the Old Deer Park, Eichmond, upon a low mound, on fiat 

 land adjacent to the Thames. 



The monthly temperature tables accompanying this com- 

 munication include the average daily minimum and the daily 

 maximum, the absolute lowest and the highest temperature, the 

 daily range of temperature, and the mean temperature, the 

 latter being the simple mean of the daily lowest and highest 

 temperatures (Table I.). The figures in itahcs for the first nine 

 months of 1881, at Waddon, have been interpolated, as the 

 Stevenson screen was not estabhshed till August of that year. 

 They have been computed on the assumption that the tempe- 

 rature at Waddon for the months in question preserved the 

 same ratio to that at South Norwood and Beddington combined, 

 as in the other years of the series. For convenience of reference, 

 separate tables have been prepared of the daily lowest (Table II.) 

 and highest (Table III.) temperatures, and the daily range 

 of temperature (Table IV.) at the five Croydon stations, and of 

 the mean monthly and annual temperature /Table V.) at the 

 eight stations where continuous records have been maintained. 



