320 



NOTICES OF AUTHORS. 



The friability and minute division of the soil to 

 which Mr Cruickshanks refers, existing around the 

 bulbs of trees, can only be of utility where the soil is 

 too adhesive. Light soil is often injm-ed by being 

 cropped by plants which tend greatly to reduce ad- 

 hesion — what the farmer styles being diiven : be- 

 sides, all luxuriant annual crops render adhesive soils 

 friable ; and, remaining for a time under natural 

 grass, gives what is termed a turfiness to soils, which 

 continues for several years, and which renders both 

 adhesive and light soils more productive, preventing 

 the adhesive from sinking down into mortar under 

 cultivation, and the light from losing all adhesion or 

 granular arrangement. 



There is, no doubt, a disposition to accumulate 

 vegetable deposit in forests, from the moistness, cool- 

 ness of the ground, and shade, not tending so much 

 as the sunshine and exposure of open country to dis- 

 sipate or volatilize the residuum of the decayed 

 leaves and roots. In a lower latitude, beyond the 

 line of peat formation, this will have some influence 

 to increase the depth and richness of the vegetable 

 mould ; but, in Scotland, where cold till bottom pre- 

 vails, more injury will result from forest tending to 

 throw the debri of vegetation into combinations un- 

 favourable to the nourishment of plants (such as peat 



