SCIENCE WITH PRACTICE, 1812 TO 1845 97 



by a ' pash' of rain. The effect of this drainage was to 

 wash the soil bare from the ridges into the furrows, and 

 thence into the adjoining stream ; thus the high parts 

 were too poor, and the lower too wet, to yield crops. If 

 the rain descended with any force, it ran along the surface, 

 carrying with it the manure and the richness of the soil. 

 Every river flowed turbid after a storm, laden with the 

 wealth of the land. 



The discoverer of the science of thorough drainage was 

 Smith of Deanston. It had indeed been extensively 

 practised in Essex, Suffolk, and Leicestershire, where land 

 was drained by trenches filled up with haulm, ling, straw, 

 or turf, and covered over. The practice of this system has 

 been traced back in Essex to 1644 ; but in the nineteenth 

 century it had hardly travelled out of the eastern counties. 

 Smith of Deanston had watched the effect of turf furrow- 

 drains in carrying off bottom water on the flat clay lands 

 of Stirlingshire. In 1806 he went to reside in Perthshire. 

 Tliere it occurred to him that the same system might be 

 employed to carry off the surface water which stagnates on 

 clay soil, rendering the land cold and tenacious in wet 

 seasons, hard and unworkable in dry weather. .In 1823 

 he began to try the experiment on a small farm at Deans- 

 ton, and from 1834 onwards made known his extraordinary 

 success to agriculturists. 



The advantages of his system were at once evident, 

 and now scarcely need remark. The soil cannot retain by 

 attraction more than a certain amount of water ; it must 

 get rid of the rest by evaporation or superficial discharge. 

 If the water runs off the surface, the land is deprived of 

 one of the richest of fertilising agencies. Not only is rain 

 heavily charged with ammonia, carbonic acid, and other 

 gases, but it is the only carrier of heat downwards. The 



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