Meteorological Observations. 89 



21. — On Meteorological Observations. 



By Henry Storks Eaton, M.A., late President of the 

 Meteorological Society. 



Read ^■^rd March, 1881. 



The area occupied by the Croydon Microscopical and 

 Natural History Club is well defined. It is about 30 miles 

 from East to West, and 20 miles from North to South. It is 

 bounded by the river Darent on the East, by the Mole on the 

 West, the Thames on the North, and includes the Gault 

 formation to the South ; but for the purpose of the present 

 paper the Southern boundary may be described as the escarp- 

 ment of the North Downs, which here extends from ENE.to 

 WSW., as a tract of table-land from 650 to 850 feet above the 

 sea, broken by gaps at Caterham and Merstham. The highest 

 point is Botley Hill, about 7:^ miles south-east of Croydon, 

 near Titsey. The general inclination of the ground imme- 

 diately north of the Downs is a gentle slope towards the 

 Thames, interrupted by numerous deep dry coombes and 

 valleys in the chalk leading to the comparatively low-lying 

 Tertiaries nearer London. The town of Croydon is situated 

 at the junction of the chalk and the more recent formations, 

 the elevation of the ground within its precincts varying from 

 120 to nearly 300 feet above the sea, and sea-level is attained 

 at the river Thames in London. This configuration of the 

 ground, and the vast extent of London included in the district 

 and lying to the north of it, are the main features which deter- 

 mine the local peculiarities of our climate. Within this area 

 are situated the two chief meteorological observatories of the 

 kingdom, viz., the Royal Observatory, Greenwich, and the 

 Kew Observatory. At both of these there is a continuous photo- 

 graphic registration of the movements of the barometer and 

 thermometer besides the registration by self-recording instru- 

 ments of the direction and force of the wind, the fall of rain, 

 and the amount of sunshine. The scheme of observation is, 

 in fact, too comprehensive for private individuals, and demands 

 a staff of observers trained specially for the work. Inde- 

 pendently of these, our domain is on the whole well represented 

 by meteorological observers — persons who devote both time 

 and trouble to the work for the pure love of knowledge. There 

 are at least forty stations where the fall of rain is registered. 

 Then there are the more comprehensive observations of Mr. 

 Corden, Mr. Latham, and Mr. Mawley in Croydon itself. The 

 two latter gentlemen include in their programme far more than 

 is usually attempted by private observers. Mr. Latham 

 registers the temperature of the ground down to 50 feet below 

 the surface, and carries on experiments on the percolation of 



