Book III. IRRIGATION. 



723 



Sect. I. Inngation, or the Pre])aration of the Surface of Lands /or tfte propabk 

 Application of Water. 



4381. Irrigation in its different forms may be considered an operation of culture as 

 well as of permanent improvement. It is accordingly in many cases effected by tenants, 

 but always, as in the case of improving vvastes, in consequence of extraordinary encou- 

 ragement from the landlord, by long leases, money advanced, or other advantages. 



4382. The application of water to the surface of lands for the purpose of promoting 

 vegetation has been practised, as we have seen (141.), from the earliest ages in warm coun- 

 tries. Solomon made him gardens, and orchards, and pools of water to water therewith 

 the wood that bringeth forth the trees. (Ecclesiastes.) The art was taught by nature in 

 the overflowing of the Nile and other rivers. Water is an essential article for the cul- 

 ture both of the cereal and pasture grasses, and indeed of most herbaceous crops, in all 

 the tropical climates, and even in a great degree in the South of Europe, In the greater 

 part of Italy and Spain, few crops are raised without being irrigated ; and even in the 

 south of France, potatoes, maize, madder, and sometimes vines, and orange trees, (as at 

 Hieres,) have water applied to their roots, by furrows and other gutters and trenches 

 formed on the surface. The system of watering grass lands was revived in Italy in the 

 ninth century, and seems to have been practised in a few places in Britain from the 

 time of the Romans; there being meadows near Salisbury which have been irrigated 

 from time immemorial. In 1610, the public attention was called to it by Rowland 

 Vaughan, in a work entitled, " Most improved and long experienced Water Works ; con- ' 

 taining the manner of summer and winter drowning of meadow and pasture, by the 

 advantage of the least river, brook, fount, or water mill adjacent ; thereby to make those 

 grounds (especially if they be dry) more fertile ten for one." 



4383. Irrigation informer times, and in all countries, however iiTiperfect, was probably 

 much more frequent than it is now. In light and gravelly tracts of country, the greatest 

 difficulty in farming was to procure a sufficient supply of fodder for their cattle in winter. 

 Meadows were therefore indispensable, and to increase the crop of hay, watering in a dry 

 spring, and immediately (in dry summers) after the first crop was off, was constantly 

 followed. Since the practice of sowing artificial grasses, and the introduction of the 

 turnip husbandry, the custom of watering has been in such situations given up ; not only 

 because it has become less necessary than it was heretofore, but because watered meadow 

 hay is of inferior quality as well as value in the market. It is nevertheless true that the 

 herbage of very coarse boggy meadows is improved, and that of cold meagre soils is 

 accelerated and increased by it. 



4384. But the principal scientific efforts in watering lands have been made during the 

 latter end of the last and beginning of the present century, in consequence of a treatise 

 on the subject by George Boswell, published in 1780, and various others by the Rev. 

 Thomas Wright, of Auld, in Northamptonshire, which appeared from 1789 to 1810. 

 The practice, however, has been chiefly confined to England, there being a sort of 

 national prejudice, as Loch has observed (Improvements on the Stafford Estates, ^c), 

 against the practice in Scotland, though its beneficial effects may be seen as far noi-th as 

 Sutherland, where rills on the sides of brown heathy mountains never fail to destroy the 

 heath plants within their reach, and these are succeeded by a verdant surface of grasses. 

 A valuable treatise on the subject of irrigation in Scotland, by Dr. Singer, will be found 

 in The Getieral Report of Scotland, vol. ii. p. 610. In England the best examples of 

 watering are to be found in Gloucestershire and Wiltshire. In our view of this subject, 

 we shall first consider the soils and situations suitable for irrigation, and next the different 

 modes of effecting it, known as flooding, irrigating, warping, irrigation on arable lands, 

 and subterraneous irrigation. 



SuBSECT. 1. Soils and Situations suitable for Watering. 



4385. The theory of the operation of water on lands we have already developed. It 

 appears to act as a medium of conveying food, as a stimulus, as a consolidater of mossy 

 soils, as a destroyer of some descriptions of weeds or useless plants, and as the cause of 

 warmth at one season, and of a refreshing coolness at another. From these circum- 

 stances, and also from what we observe in nature, there appears to be no soil or situation, 

 nor any climate, in which watering grass-lands may not be of service ; since the banks of 

 streams between mountains of eveiy description of rock, and in every temperature from 

 that of Lapland to the equator, are found to produce the richest grass. One circum- 

 stance alone seems common to all situations, which is, that the lands must be drained 

 either naturally or by art. The flat surfaces on every brook or river, after beiiig covered 

 with water during floods, are speedily dried when they subside, by the retiring of the 

 waters to their channel. 



4386. The most proper soils for being watered are all those which are of a sandy or 

 gravelly friable nature, as the improvement is not only immediate, but the effects more 



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