On Irrigation. 275 



times been made, both in England and Scotland, extremely 

 prejudicial to the advancement of irrigation. 



The next objects are, the quality of the water, and the 

 nature of the soil and subsoil of the land proposed to be 

 irrigated. 



It is then proper to consider, how 9 and w/iere, the water 

 can be taken out of the stream. This can only be done by 

 a proper level ; and the assistance of a professed irrigator 

 will be necessary. 



Irrigation being an operation requiring considerable nice- 

 ty and skill, cannot be advantageously conducted, without 

 attentive hands to form the soil, to lay on and shift the wa- 

 ter, and to remove it; also to cut down the produce, and to 

 make it into hay. On all these accounts, a supply of trusty 

 labourers, for carrying on these several processes, must be 

 provided ( 4I3 ). 



Nor is this all. It is likewise necessary to ascertain, 

 whether there are any obstacles to the proposed improve- 

 ment, arising from the claims of millers, or canal own- 

 ers ( 4I4 ), (which are often great impediments), the interven- 

 tion of other property, or from leases granted to the farmers 

 on the estate. The command of capital adequate to the 

 expense likely to be incurred, is absolutely necessary. 



4. Of the Water calculated for Irrigation. 



Clear spring-water, in the state in which it issues from 

 the hills, (more especially where the strata are calcareous), 

 is certainly of a fertilizing quality. It is charged with a 

 considerable quantity of vital air ; near the source also, it is 

 usually warmer than other waters, and thence it answers 

 better for irrigation, more especially during severe weather 

 in winter. From these properties, there is always produ- 

 ced abundance of early succulent grass, for several yards 

 where the water first runs over the land near the spring. 

 Clear spring-water may also be used longer than foul or 

 muddy water, it being less apt to render the grass gritty 

 and unwholesome ; hence some give a decided preference to 

 clean-watered crops ( 4l5 ). The water of petrifying springs 

 is likewise highly fertilizing. 



Mountain streamlets, fed principally by springs, are more 

 at command than rivers, more convenient to be directed over 

 slopes, and also better calculated for improving grass. 



Where river-water is accessible, it is commonly loaded 

 with many enriching substances from the country, nnd the 



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