DRAINAGE. 87 



cuttings of the hedges, covered with straw. In Leicester 

 shire nearly a century ago, and perhaps earlier, a conduit 

 was formed in clay at the bottom of the drain by a super- 

 imposed turf (locally called clod-soughing); and the practice 

 is not quite exploded in that and other counties, which 

 are backward in their agriculture. Attempts, moreover, 

 were made in various parts of England to form a conduit 

 by means of a mole-plough. This instrument had a great 

 but very transient reputation. Smith of Deanston was 

 therefore by no means the author of thorough-draining, 

 but he saw much more clearly than any of his predecessors 

 the benefits to be derived from it, and he has the high 

 merit of having brought them prominently before the 

 public. No doubt whatever can exist that Mr. Smith gave 

 the first effectual impulse to the practice, and to that 

 extent his name is justly associated with thorough-draining. 

 One sentence in an article which he furnished to " The 

 Third Report of Drummond's Agricultural Museum," 

 makes a considerable approach to a right conception of the 

 advantages of thorough-draining, as they are now revealed 

 to us. 



"When soil is immediately incumbent on open rock, 

 especially on whin or green-stone, which is very open from 

 its many fissures, the land is always uniformly fertile. 

 If, therefore, we observe carefully the operations of nature, 

 we shall never be at a loss for principles to guide us in the 

 cultivation of the soil. In the last stated example, the 

 open rock under the soil affords frequent and pretty 

 uniform channels of escape for the water; hence the 

 obvious suggestion of the frequent drain system." 



So utterly innocent was poor Johnstone of any such ideas, 

 that in a chapter on " Hollow-draining in General," he 

 publishes such stuff as follows : 



" In soils that are so tenacious as to retain water on the 

 surface till evaporation carries it off, such as are found in 

 Sussex, Surrey, and in many other counties, this method 

 of draining has been tried, and found entirely to fail." 



