go 



Mr. H. S. Eaton. 



rain through different soils and on evaporation ; and he has 

 also established and maintains a comprehensive series of 

 stations for observing the fall of rain in outlying districts on 

 the North Downs, of which he has communicated to us the 

 results this evening. Mr. Mawley both notes the temperature 

 of the soil and keeps a sunshine recorder, and an anemometer 

 — I should like to see one of the latter instruments at the top 

 of the water-tower. There are also observers at Lower Nor- 

 wood, South Norwood, Beddington, Beckenham, Eltham, and 

 Caterham. 



Situated midway between London on the one side and the 

 North Downs on the other, Croydon is alternately subjected to 

 an atmosphere polluted with smoke, and to air comparatively 

 pure according to the quarter from which the wind blows. Na 

 sooner does the wind set in from the North than the sun grows 

 dim and the landscape blurred by a gloomy canopy of smoke, 

 which, when mixed with fog in winter, is sometimes so dense 

 as to oblige us to have recourse to artificial light at mid-day. 

 The evil is increasing year by year ; there is not a nook or 

 corner in the county of Surrey to which the smoke of London 

 does not at times penetrate and coat stagnant pools of water 

 with a film of carbon. The rapid growth of Croydon has 

 aggravated the nuisance, which is decidedly worse now than it 

 was ten years ago ; and the paucity of fructifying lichens on 

 our houses and on trees is a sure witness of its baleful effects ; 

 for six months in the year you cannot pluck a twig in your 

 garden without soiling your fingers ; and you may walk for 

 miles and not see a sheep with an unsullied fleece. London is 

 known tohaveahighertemperature than that dueto geographical 

 position, owing to artificial causes, but the disturbance thereby 

 produced in the climate of this vicinity has not yet been inves- 

 tigated. With the wind from any other direction than that of 

 London, the climate of Croydon is, on the whole, a pleasant 

 one. Statistics relating to it were submitted to you by Mr. 

 Corden three years ago, to which I may refer you for much 

 interesting information. 



I have already stated that the topographical configuration of 

 the ground is one of the causes that give an individuality to 

 our local climate. This is chiefly noticeable at night and in 

 the winter, when the influeince of the sun is feeble, and the 

 surface of the ground is cooled by radiation below the superin- 

 cumbent air. At such times the particles of air resting on the 

 ground become cold by contact with it, and increasing in 

 density descend the slopes of the downs, and collect at the 

 bottom of the coombes, displacing the warmer air. Creeping 

 from these as shallow streams of cold air of limited extent, they 

 gather in the wider valleys, and are the fruitful source of the 



