IRRIGATION. 



IRRIGATION. 



which nature, of its own accord, produces in a 

 juicy soil, than what water draws from a soil 

 that is overflowed. This, however, is a neces- 

 sary practice when the poverty of the soil re- 

 quires it ; and a meadow may be formed either 

 upon a stiff or free soil, though poor when 

 water may be set over it ; neither a low field 

 with hollows, nor a field broken with steep 

 rising ground, are proper ; the first, because it 

 contains too long the water collected in the 

 hollows ; the last, because it makes the water 

 run too quickly over it. A field, however, that 

 has a moderate descent may be made a mea- 

 dow, whether it be rich, or so situated as to be 

 watered ; but the best situation is where the 

 surface is smooth, and the descent so gentle 

 as to prevent either showers, or the rivers that 

 overflow it, remaining too long; and, on the 

 other hand, to allow the water that comes over 

 it quietly to glide off; therefore, if in any part 

 of the field intended for a meadow, a pool of 

 water should stand, it must be let off by drains, 

 for the loss is equal either from too much wa- 

 ter or too little grass." (Col. lib. ii. c. 16.) 

 Pliny tells us that " meadows ought to be wa- 

 tered immediately after the spring equinox, 

 and the waters restrained whenever the grass 

 shoots up into stalk." (Nat. Hist. lib. xviii. c. 

 27.) When, after the fall of the Roman Em- 

 pire, agriculture, in common with all other 

 sciences, rapidly declined, a very remarkable 

 exception to this melancholy result of slavery 

 and despotism was presented in the case of 

 irrigation, which was carried on and extended 

 through the long period of the dark ages with 

 equal zeal and success. This was more espe- 

 cially the case in Lombardy, where it was cer- 

 tainly prosecuted on a very bold and profitable 

 scale long before 1037. The princes of Lorn- 

 hardy patronised and followed the example of 

 the various religious establishments which 

 then monopolized all the wealth and learning 

 of the land, in extending the employment of 

 water in all possible directions. The monks 

 of Chiazevalle, in particular, were so cele- 

 brated for their knowledge of this branch of 

 agriculture, and of hydraulics in general, that 

 the emperor Frederick the First, in the 13th 

 century, very gladly sought their advice and 

 assistance. This system has ever been zeal- 

 ously and carefully extended and improved in 

 every possible way. The waters of the chief 

 rivers of the north of Italy, such as the Po, the 

 Adige, the Tagliamento, and of all the minor 

 streams, are employed in irrigation. There is no 

 other country, which possesses an extent of rich 

 water meadows equal to that of the Lombards. 

 The entire country from Venice to Turin may 

 be said to be formed into one great water mea- 

 dow : yet the irrigating system is not confined 

 to grass lands; the water is conveyed into the 

 hollows between the ridges in corn lands, into 

 the low lands where rice is cultivated, and 

 around the roots of vines. From Italy the 

 practice extended into the south of France, 

 into Spain, and then into Britain. In the 

 States of Lombardy, the water of all the rivers 

 belongs to the state ; in those of Venice, the 

 government extends its claims to that of the 

 smallest springs, and even to collections of 

 rain water, so highly, for the use of the cul- 

 670 



tivator, is water of every kind valued in the 

 north of Italy. It is necessary, therefore, in 

 Lombardy, to purchase from the state the 

 water taken from the river; this may be taken, 

 by means of a canal, through any person's 

 grounds, the government merely requiring the 

 payment of the value of the land to the pro- 

 prietor, and restraining him from carrying his 

 channel through a garden, or within a cer- 

 tain distance of a mansion. The water is sold 

 by the government at a certain rate, which is 

 regulated by the size of the sluice, and the 

 time the run of water is used ; this is either 

 by the hour, half-hour, or quarter, or by so 

 many days at certain periods of the year; the 

 right to these runs of water is regularly sold like 

 other property. Arthur Young gives an account 

 of the sale of an hour's run of water through a 

 sluice near Turin, which produced, in 1778, 

 1500 livres. The rent of the irrigated lands in 

 the north of Italy is, upon an average, more 

 than one-third greater than the same descrip- 

 tion of land not watered. (Com. Board of dgr. 

 vol. vii. p. 189.) 



In Bengal, wells are dug in the highest part 

 of their fields, and from this, by means of bul- 

 locks and a rope over a pulley, water is raised 

 in buckets, and conveyed in little channels to 

 every part of the field. No attempts at culti- 

 vation are here made without the assistance 

 of water, obtained by some mode or other. 

 (See IXDIA, AGRICULTURE OF.) The art of 

 irrigation was not confined to the Old World. 

 The Mexicans practised it long before the days 

 of Columbus; they collected the mountain tor- 

 rents, and conducted their waters to their lands 

 in proper channels, with much care and ad- 

 dress. It was only towards the termination of 

 the 17th century that water meadows were 

 constructed in Britain upon any thing like a 

 regular system. Of these, those in Wiltshire, 

 which are amongst the most celebrated in 

 England, especially those in the Wyley Bourn, 

 were made between 1700 and 1705. Those 

 of Hampshire and Berkshire were constructed 

 about the same period, but they were at first 

 formed very inferior to the modern noble wa- 

 ter-meadow lands of those countries. Great 

 improvements were made towards the conclu- 

 sion of the 18th century, through the publica- 

 tions of G. Boswell on Meadow Watering in 

 1780, and of the Rev. T. Wright, of Auld, in 

 Northamptonshire, whose writings appeared 

 at intervals from 1789 to 1810. It is notice- 

 able that the water employed for these cele- 

 brated southern meads is perhaps the most 

 clear and swift flowing of all the English 

 rivers; issuing from the chalk formation, it is 

 equally copious and transparent. Some of the 

 chief advantages, therefore, of irrigation may 

 evidently be derived from almost any descrip- 

 tion of water; for it is proved by the good 

 effects produced by the brilliant chalk-waters 

 of the south of England, and the still greater 

 fertilizing effect of those surcharged with or- 

 ganic matter, as in the Craigintinny meadows, 

 near Edinburgh, that there is no water too 

 bright, or too full of impurities, to be useless 

 for the purposes of irrigation. 



I propose, in this paper, to investigate the 

 chemical properties of river water, and of the 



