ADVANTAGES OF DRAINING. 325 



frequently very steep, and thxis oppose formidable ob- 

 stacles to the use of the water. Yet irrigation is rather 

 increasing than diminishing in Scotland ; there are spots 

 where, to use the words of one of their own poets 



" a free and porous soil 



Upon a gravelly bed, at all times drinks, 

 Yet ne'er is quenched. Who owns a soil like this, 

 If through his fields a little mountain stream, 

 Not sunk in channel deep, but murmuring down 

 'Tween gently sloping banks, a mine of wealth 

 Possesses in that stream." 



It may seem contradictory to state that, notwith- 

 standing the great advantages derived from irrigation, 

 no land will really prosper that is not kept dry, rich, 

 and clean. But what is here meant by dry, is in a 

 healthy condition to receive moisture. There must be 

 no stagnant water underneath the surface, making the 

 land cold and unhealthy ; but the soil, even that which 

 is most abundantly irrigated, must be capable of quick 

 and healthy drying between the floodiugs ; that is, the 

 drainage, as well as the irrigation, must be well attended 

 to ; indeed, the drainage of the subsoil is frequently 

 considered a necessary preparation for the flooding of 

 the surface, the great object being to pi-event stagnation, 

 and keep up a healthy circulation of the fluid. 



In former days draining was confined to land that 

 had become seriously wet and marshy ; but it is now 

 practised on soils which, to an inexperienced eye, would 

 seem perfectly dry. It sometimes happens that there 

 are deficient crops on particular fields, without any 

 apparent reason. Good farming is bestowed on them in 

 vain, for, however well managed, the crops become sickly 

 in colour, and are evidently retarded in their progress. 

 The farmer soon detects the real cause of the mischief, 

 which is a superfluity of water beneath the soil. There 

 are several signs by which he is convinced that this is 

 the case ; for instance, while useful plants decay, others 

 spring up which he knows to be peculiar to wet soils, 



