284 DENUDATION OF THE LAND. Chap. YI. 



leeward side, from the upper part having 

 curled over the lower part. During one un- 

 usually heavy south-west gale with torrents 

 of rain, many castings were wholly blown to 

 leeward, so that the mouths of the burrows 

 were left naked and exposed on the windward 

 side. Eecent castings naturally flow down 

 an inclined surface, but on a grassy field, 

 which sloped between 10° and 15°, several 

 were found after a heavy gale blown up the 

 slope. This likewise occurred on another 

 occasion on a part of my lawn where the 

 slope was somewhat less. On a third occasion, 

 the castings on the steep, grass-covered sides 

 of a valley, down which a gale had blown, 

 were directed obliquely instead of straight 

 down the slope ; and this was obviously due 

 to the combined action of the wind and 

 gravity. Four castings on my lawn, where 

 the downward inclination was 0° 45', 1°, 3° and 

 3° 30' (mean 1° 49') towards the north-east, 

 after a heavy south-west gale with rain, were 

 divided across the mouths of the burrows and 

 weighed in the manner formerly described. 

 The mean weight of the earth below the 

 mouths of burrows and to leeward, was to that 



