iS38.] 



FARM KliS' REGISTER. 



25 



of consimciinir them, hiiveulreiuly he.e,ii explain- 

 eil. Its elfvaiioii ami slope sIkiuKI d;'pi^iiJ iipuii 

 the de,<froi' o("oxpo.sure to the winds and lidvs, and 

 the hiuijriit to whicli the urreatesl tides aro, accus- 

 tomed to rise. The elevation may vary irom five 

 to fifteen feel, and the front slope irom twenty in- 

 ches to five leet lor every foot of hcigiit; the back 

 slope beiniT irenerally one half less than the otlier. 

 In every case, liie hank should be at least two leet 

 hij^her than ihe water during the greatest spring- 

 tides. In determining the slope, great care must 

 be taken lo proportion it to lite force of the sea, as 

 nothing can be more ruinous than to make the 

 bank too hold or upright. It has been well re- 

 marked, that a wave which I'alis on a flat surlace 

 dies without a straggle, while one that is stemmed 

 by an abrupt rock strikes with tenlbld Ibrce. The 

 evil of not estimating properly the force of the 

 eea, is remarkably exemplified in the case ot some 

 extensive embankments at the mouth of the river 

 Cree, in the county of Wigton. The banks on 

 both sides of this river were made of the same di- 

 mensions, being about four leet and a half high, 

 and nine iljet broad in ilie base, without adverting, 

 that the northern bank is exposed to the south- 

 west winds, which in that quarter always bring 

 up the hiirhest tides. It happened, accordingly, 

 that at the first high tide, the embankments on the 

 northern side were almost totally destroyed, while 

 only a few l)reaches were made on those of the 

 southern. To have enabled the former to with- 

 stand the superior force which assniled them, the 

 dimensions ought perhaps to have been double 

 those of the latter. 



Along the back ofall sea-banks, trenches should be 

 made in the same manner as in river embankments, 

 and sluices erected at diti'erent parts, to sliut of i hem- 

 selves against any external water,an(l to open wlien 

 the tide ebbs, to let out any water ti-om within. 



In every case, where an external valve is re- 

 quired for the discharge of the surface-water of an 

 embanked area, and where it is liable to be choked 

 up with sand or gravel, as behind a shilling 

 beach, or in front of the open sea, means must be 

 taken to defend the valve from stopf)age, or great 

 attention be <;ivei! to keen it clear. In some situ- 

 ations, the valve is 90 liable to be buriedj and the 

 channel closed up, by every spring-tide, or iznla of 

 wind, that the only effectual remedy is to make a 

 covered channel through (he line or ridge of the 

 beach into the sea; and this must be made strong 

 enough to sustain the weight of the heaviest 

 breakers. This expedient has been adopted upon 

 Lord Cawdvir's estate in Pembrokeshire; and 

 though found extremely expensive, yet the ad- 

 vantage fraineu '..i so great, as to render the un- 

 dertaking profitable. In cases of less extremity, 

 the valve might be sufTiciently guai\lcd by a pile 

 fence or a |)ier. carried out from trie foot of ihe 

 embankment, across the known drifi of the beach, 

 the sand, which mio-ht accumulate behind this 

 fence, being removed from time to lime. Where 

 the eea reaches to the foot of the embankment, it 

 has been Ibund necessary to erect two flood-gales, 

 the one within to secure the outfall channel, and 

 the other on the outside to ward off the waves, 

 and prevent them injuring the irmer works. The 

 outer gate may in this case be lifled; but though 

 a considerable (luantity of water should be admit- 

 ted, yet its force being broken, the inner valve will 

 remain undisturbed. 

 Vol. VI— i 



It sometimes happens, that salt marshes, partic- 

 ularly those at the sides of estuaries, are situated 

 so low as to lie conslanlly under water. In cases 

 of this kind, the following mode of drainage and 

 embankment, practised on a niarsli near Mara- 

 zion, in Cornwall, may with pro|;riety \ye adopted. 



Tlie marsh in (pieslion was situated on the 

 banl< of a river, and separated from the sea by a 

 tract of sand consisting of about ecventeen acres. 

 It lay always under two or three feet of water, 

 and Ihe sea flowed over it at spring-tides. As it 

 was found impossible to take off all the surface- 

 water bv the river, a stiuare wooden pipe of nine 

 inches diameter was carried through below tlie^ 

 tract of sand above mentioned, ti-om the edge of 

 Ihe marsh to that part of the shore called half-ebb, 

 which was eight feet lower than the surface of the 

 marsh. At the mouth of this pipe, a reservoir, of 

 18 feet square and eight feet deep, was cut out, 

 and from this reservoir a trench of three feet deep 

 and five wide was extended on each side, between 

 the sandy soil and the marsh. At the distance of 

 every sixty yards, cuts were made from this main 

 trench across the marsh, by which the whole area 

 was divided into oblong square fields. By means 

 of these trenches, all the suriace-water was con- 

 veyed into the reservoir, and fiom the reservoir 

 conducted by the pipe into the sea. At both ex- 

 tremities, the pipe weis guarded by valves, which 

 shut at the ajproach of the tide, and opened upon 

 its regress, to let off the water which had collect- 

 ed in the interval; and before the valves, iron bars 

 were also placed, to prevent the intrusion of extra- 

 neous bodies. When the surface-water of the 

 marsh had been thus removed, a strong embank- 

 ment of turf was erected on those sides of the 

 marsh where it was exposed to the influx of the 

 sea; and, by a judicious course of management, 

 the ground became, in the course of a Itnv sea- 

 sons, covered with rich crops. The reporter re- 

 marks, that the whole of this improved ground, 

 including the marsh, the sand tract next the sea, 

 and a piece of croft or elevated crround behind the 

 marsh, "has been productive of considerable ad- 

 vantages to the public, particularly to the poor. 

 Four hundred persons yearly receive turf from it, 

 two hundred and fiiiy are led most plentifully with 

 potatoes, which are plunted here by very poor 

 people^ who are, in consequence of having land 

 given them, become uncommonly industrious; and 

 the whole neiiihborhood, by its drainage, have got 

 rid of low nervous fevers and agues, with which 

 it was commonly pestered." 



The tracts ofsalt marshy ground, which have 

 been reclaimed in Scotland, are not very numer- 

 ous; but it is hoped the profit which these have 

 nflorded, may tend to induce further exeriions in 

 tliis liranch of improvement. Perhaps there is no 

 I'lace in which more valuable acquisitions have 

 been made in this manner, than in the island of 

 Islav. under the direction of its intelligent proprie- 

 tor, 'Mr. Campbell of Shawfield. At the head of 

 an arm of the sea called Loch Gruinart, an em- 

 bankment has been executed, by which fijur hun- 

 dred acres of land, which formerly composed an 

 useless salt marsh, have been brought under the 

 plough. In making this embankment, it was 

 found that a considerable stream, which dis- 

 charged itself into the head of the loch, impeded 

 the operation of the ftood-gates; and, as the only 

 effectual method of removinjj this serious incon ■■ 



