Book III. SUBTERRANEOUS IRRIGATION. 667 



after it has been for two or three years in cultivation. In the quality of warped land, there 

 are ntiost essential differences, some will be very strong, and in the same field some will 

 be very friable. The land nearest the drain is in general the lightest, owuig to the 

 quantity of sand that is deposited as soon as the water enters the field . the land farthest 

 from the drain is in general the best. The produce of warped land varies much, but 

 in general it may be stated as abundant. (Code, 315.) 



SuBSECT. 1. Of the Irrigation of Arable Lands and of Subterraneous Irrigation. 



4124. The irrigation of arable lands is universal in warm countries, and even in the 

 south of France and Italy. The land is laid into narrow beds, between which the 

 water is introduced in furrows during the growth of the crop, and absorbed by the soil. 

 In other cases, the crop is grown in drills and the water introduced between each row 

 in the furrow. In this mode of irrigation no collecting drains are required, as the 

 whole of the water laid on is absorbed by the soil. The principal expense of this oper- 

 ation is that of preparing the lands by throwing the surface into a proper level or levels ; 

 the main or carrier is conducted to the higher part of the field, and the rest is easy. 

 A particular description of the practice, as carried on in Tuscany, is given by Sigismondi. 

 (Agr. de la Toscane) Some account also of tlie practice in Spain and the East Indies, 

 will be found in our outline of the agriculture of these countries. 723. and 908.) 



4125. Subterraneous irrigation appears to have been- first practised in Lombardy, and 

 first treated of by Professor Thouin. [Annales du Musee, cfc.) It consists in saturating 

 a soil with water from below, instead of from the surface, and is effected by surround- 

 ing a piece of ground by an open drain or main, and intersecting it by covered 

 drains communicating with this main. If the field is on a level, as in most cases where 

 the practice is adopted in Lombardy, all that is necessary is to fill the main and keep it 

 full till the lands have been sufficiently soaked. But if it lies on a slope, then the lower 

 ends of the drains must be closely stopped, and the water admitted only into the main 

 on the upper side : this main must be kept full till the land is soaked, when the mouths 

 of the lower drains may be opened to carry off" the superfluous water. The practice is 

 applicable either to pasture or arable lands. 



4126. In Britain, subterraneous irrigation has been applied in a very simple manner 

 to drained bogs and morasses, and to fen lands. All that is necessary is to build a 

 sluice in the lower part of the main drain where it quits the drained grounds, and in 

 dry weather to shut down this sluice, so as to dam up the water and throw it back into 

 all the minor open drains, and also the covered drains. This plan has been adopted with 

 success, first, as we believe, by Smith, of Swineridge Muir, in Ayrshire, and subse- 

 quently by Johnston, in the case of several bog drainages executed by him in Scotland. 

 It is also practised in Lincolnshire, where it was introduced by the advice of the late 

 engineer Rennie, after the completion of a public drainage at Boston. 



Sect. III. Of the Artificial Means of Procuring Water for the Use of Live Stock' 



4127. Water is sujyjdied by nature in most parts of the British isles, and retained with 

 little art both at farmeries and in fields. There are exceptions, however, in different 

 districts, and especially in chalky soils, gravels, and some upland clays. In these cases 

 water is procured for cattle by some of the following means: By conducting a 

 stream, from a distant source, as in a work of irrigation; by collecting rain- 

 water from roads, ditches, or sloping surfaces, in artificial ponds, or reservoirs; 

 by collecting it from the roofs of buildings, and preserving it in covered cisterns ; 

 by sinking a well, or a pipe, either in the field, or the farm yard; and by artificial 

 springs. 



4128. An artificial streain will in most cases be found too expensive an operation to 

 be undertaken for the supply of drinking water for live stock ; but this purpose may 

 frequently be combined with that of watering lands or driving machinery. In the 

 North Riding of Yorkshire, there is a tract extending for many miles, entirely destitute 

 of water, except what flows along the bottoms of the deep valleys by which it is in- 

 tersected, and little relief could consequently be afforded by streams thus distantly and 

 inconveniently situated, to the inhabitants of the uplands, or their cattle. About the 

 year 1770, a person of the name of Ford devised the means of watering this district, 

 by means of rills brought from the springs that break out at the foot of the still loftier 

 moorland hills, that run parallel to and to the north of this tract, in some instances at 

 the distance of about ten miles. The springs he collected into one channel, which he 

 carried, in a winding direction, about the intervening tract, according to its level, and 

 along the sides of the ralleys, until he gained the summit of the arid country which he 

 wished to supply with water ; and when this was accomplished, the water was easily 

 conveyed to the places desired, and also to the ponds in all the fields, over a considerable 

 tract of ground. 



