IRRIGATION, 



pofe tlian that which arilcs from others that do not contain 

 fuch materials. The difference in the effects, often fo vifibly 

 produced, has been accounted for, from watering one field 

 from a fpring iffuing out of a chalky fiil, over thofe which 

 take their rile in another, fimilar in every rcfpeCt and manage- 

 ment,except that the water applied arifes in, or flows through, 

 a fwamp or morafs, compofed chiefly of peat earth, or proceeds 

 from fituations known to contain none of thefe fubftances. 

 However, the fad is unq\iellionably ellablilhed,' that the 

 water of rivers which run through comparatively level and 

 fertile countries, is not only better than that of fuch as have 

 their courfcs through mountainous, unproduftive trafts, but 

 fuperior to all others, as every different llrcamlet adds a new 

 accelfion of fertilizing materials, which, being difperfed over 

 the furface of the meadows, in their fine and attenuated 

 ftate, cannot avoid adding a confiderable degree of improve- 

 ment to the lands. 



It is conceived by Mr. Marfhall, that if the art, as it 

 BOW Hands, were flruck out on principle, it mut^ have been 

 cm that of animal circulation ; to which the operation of 

 meliorating grafs-lands with water, through the means of 

 floats and drains, is perfeclly analogous. The floats are ar- 

 teries, conveying the circulating fluid to every part of the 

 fubjeft, imbuing every atom : the drains, veins, collecting 

 the fcattered fluid, and conveying it back to its natural 

 channel. But that, in lefs figurative language, the floats 

 may be conlidered as trenches, receiving, by the means of 

 flood-gates, as occafion requires, the water of a river, brook, 

 or rivulet, and conveying it along the upper margin, and 

 upon the tops of the natural or artificial fwells of the field 

 of improvement : — the drains, counter-trenches, ftretching 

 along the lower margin, and winding in the dips and hollows, 

 to receive the waters fpread over the furface by the floats. 



Each fet of trenches, whether of floats or drains, bears 

 more or lefs refemblance to a tree, with its trunk and 

 branches : the branches of the floats increaflng in number, 

 and dmiuiifhing in lize, as they proceed from the river or 

 other fource ; thofe of the drains, on the contrary, diminilh- 

 ing in number, and increafing in fize, as they approach the 

 receptacle or place at which the water is to be difcharged. 

 And it is further remarked, that when the water is at work, 

 ar- it is properly enough termed, the entire furface, fup- 

 poling the operation to be pcrfeft, is covered with one con- 

 tinued flieet of livuig water, purhng (lowly and evenly over 

 t-very part, an inch or more deep. If the grafs be very 

 ftiort, the water is feen, and has a beautiful as well as a pro- 

 fitable effect : if not, it lleals, unfeen, among the herbage, or 

 (hews itlrlf, partially : it being impoflible, in praftice, to 

 render the (heet throughout of an uniform depth or thick- 

 nefs, as it mud naturally pafs off quicker in fome fituations 

 than otliers. 



From this general idea of the method of watering grafs- 

 hinds, on the modern principle, it is clearly fliewn that a 

 dead flat, a perfeft level, is, of all others, the leall adapted 

 to the praftice. A pcrfcci level, however, feldom occurs in 

 nature ; inequalities, fuflicicntly to promote a circulation of 

 water on the turfy furface, may generally be difcovered, if 

 jjdicioufly fought. In the midland counties, Mr. Marfhall 

 has feen in the practice of a fuperior manager a beautifully 

 limple expedieiit pracfifed, to find out the inequalities of a 

 piece of ground nearly flat : which is that of covering it 

 with water, and prcferving the level by the means of level- 

 hng pegs, flumps or piles driven down in various parts to a 

 level with the furface of the water ; fo that, after the water 

 was let off, the level Hill remained. The parts laft covered 

 were, of courfe, the proper ground for the floats ; the parts 

 lall freed for the drains ; art being ufed, where wanted, to 



Vol. XIX. 



give additional advantage to the natural inequalities which 

 maybe prefent. But fituations in general (water-formed 

 lands excepted), abound, he thinks, fufficiently with ine- 

 qualities of furface : either natural, as the fwells and hol- 

 lows of lands, lying out of the way of floods, and having 

 never been ploughed : or artificial, as thole which have been 

 raifed by the ])lough into ridge and furrow : in this cafe the 

 ridges receive the floats, the furrows the drains : in that, the 

 plummet is the guide to the floats ; the water they throw 

 out, to the drains or cuts to be formed. 



The fame writer adds, that, in the above diftrift, he has 

 feen the fide of a hill watered with rain-water, from a road 

 running along the top of it : the fame trench, in this cafe, 

 acting as float and drain, running a zig-zag along the face of 

 the (lope, the lower folds catching the water fpread out 

 by the upper ; and that he has hkevvife obferved feveral 

 inilances of ridges and furrows being watered from fimilar 

 fources. In thele cafes, whether the natuial defcent of 

 the lands was littla or great, the floats were opened upon 

 the ridges with clods of turf cut out of the trenches, placed 

 at diflances proportioned to the defcent, to check the cur- 

 rent fufficiently, to force the water out of the trench above, 

 yet leaving it a fiifRcient pafl'age, to fuffer it to carry down 

 a fupply to the parts below. He has alfo met with one or 

 more inilances in which ridges and furrows have been levelled 

 at an exceffive cofl, by paring off the turf, throwing down 

 the ridges by hand, and replacing the turf, giving the fur' 

 face one regular gentle defcent ; and this, notwithftanding 

 it is allowed by thofe who may be flyled mailers in the 

 art, that the quicker the circulation the more beneficial the 

 effeft. Upon the whole, it appears pretty evident, that 

 the operation, though fcientific, can feldom be rendered 

 mechanical. Straight lines and plain furfaces can feldom 

 be had, but at a great, and, frequently, an unneceffary ex- 

 pence. The given fituatiou of the ground fhould be con- 

 fulted and maturely lludied before the work be fet about. 

 Every fcite may be faid to require a different arrangement 

 of trenches. Of courfe, no man ought to fet about a work 

 of fo difficult a nature until he has lludied its principles, and 

 made himfelf mailer of its theory ; nor then, without the 

 afTiflance of praftice in himfelf, or others whom he can em- 

 ploy for the purpofe. 



It is conceived that to expatiate on the utility of watering 

 grafs-lands would be a wafle of words. In fituations where 

 a lufficient fupply of water, of a fertilizing quality, can be 

 commanded at all feafons, it ranks indubitably among 

 the hi^hell clafs of improvements. Much, however, it is 

 fuppofed, depends on the quality of the water ; not on its 

 colour or clearnefs, but the Ipcciiic quality of the fufpended 

 particles. Waters, in their natural flate (not purified by 

 diilillation), more efpecially fpring waters, tliougli perfectly 

 tranfparent and pure to the eye, ai-e as various in quahty as 

 foils, owing to earthy and other particles being fufpended 

 in them imperceptibly to the eye, requiring the aid of 

 chemillry to deteft them ; hence hard water, foft water, 

 wholefome waters, medicinal waters, &c. The effects of 

 clear fpring water have been found flrikingly evident in 

 various cafes of this fort of management in different place-s 

 in this country. 



But although very much depends on the quality of water 

 for the purpofe of meliorating grafi-lands, much alfo de- 

 pends on the quantity ; on having a fnfficient fupply at 

 all feafons. With this there are, perhaps, few waters which 

 might not be rendered beneficial to grafs-land, if tluowii 

 over it at proper feafons, and in proper quantity. Whhout 

 it, the benefit, it is poflible, may not be adequate to the 

 expence. The moll obvious advantage of watering grafs- 

 5 N Lnds, 



