Elevation. 37 



vourable to the culture of the land, by allowing a ready 

 descent to any water with which the surface may be encum- 

 bered ( l31 ). Abrupt elevations however, very much in- 

 crease the labour and expense of cultivation ; and the soil, 

 in the highest parts of the field, becomes shallower, by every 

 operation of tillage. 



Hilly countries have many disadvantages. On their slo- 

 ping sides, the finer parts of the clay and mould are washed 

 away, while the sand and gravel remain. Hence in such 

 districts the soil often wants a proper degree of tenacity for 

 supporting corn crops ( l3z ). A great part of the manure 

 that is applied, in such situations, is likewise soon lost. From 

 various causes also, they are colder than the plains. They 

 are more distant from the heat of the great mass of the earth, 

 and in a manner cut off from its influence. The atmos- 

 phere around them is liable to be often set in motion ; and 

 thus any heat which may occasionally be accumulated, is ra- 

 pidly carried away. The attraction of moisture by high 

 grounds, is another cause of their being colder. 



In considering the crops to be raised on any particular 

 farm, much attention ought to be paid to the quality of the 

 soil, its natural shelter, and its height above the level of the 

 sea. In regard to elevation, it has been found, that in lati- 

 tudes 54 and 55, wheat cannot be sown at an altitude of more 

 than 500 feet, with any probable chance of profit; and even 

 at that height, when the soil is heavy, and the situation un- 

 sheltered, the grain will be late in ripening, and of inferior 

 quality. But where the soil is a sandy loam, in good con- 

 dition, and the ground sheltered by hills, wheat of a medium 

 quality has been produced, in favourable seasons, at from 

 700 to 800 feet above the level of the sea. 



In the warm vales, among the hills, in the upper ward 

 of Lanarkshire, large crops of oats have been reaped, and 

 grain of good quality produced, in situations from 1000 to 

 even 1200 feet above the level of the sea. Oats have like- 

 wise been grown at Dubrach, in Braemar, (Aberdeenshire), 

 at 1294 feet, and at Leadhills, in Lanarkshire, at 1564 feet 

 of altitude ; but these were only in small patches, richly 

 manured, and the grain was seldom fully ripe, or properly 

 harvested ( l33 ). 



In England, from 600 to 700 feet may be reckoned the 

 usual maximum of elevation, for the more common sorts of 

 grain ; and in backward seasons, the produce at this height is 

 of small value, and sometimes yields nothing but straw ( l34 ). 

 In calcareous soils, however, (as in the Gloucestershire and 



