242 



NEW ENGLAND FARMER. 



must be taken to proportion it to the force of 

 ihe sea, as nothinqr can be more ruinous, than 

 to make the bank too boM or upright. A wave 

 u-hich tails on a tlat surface dies without a strug'- 

 gle, while one th.il is stemmed by an abrupt rock 

 strikes with tenfold force. 



Alon'.'' Ilic back of all sea-hanks, trenches 

 should be made, and sluices erncted at dilTercnt 

 parts to shut of themselves against any exter- 

 nal water, and to open when the tide ebbs to let 

 out any water from within. 



These sluices should be so constructed as to 

 let the water out of the marsh without admit- 

 ting water t'rom the sea. A method by which 

 this may be accomplislied is described bv a wri- 

 ter in the American Farmer, vol. ii, p. 211, and 

 is, in s\il)stance, as follows. It has been found 

 that the common gates, heretofore u'ed to ex- 

 clude the tides t'rom marshes, will not always 

 answer. The tide creeps in so .slowly, that it 

 ■will not shirt such a gate in time, nor press it 

 too with sufficient firmness to exclude the iiood 

 tide ; for chips, weed-;, &,c. were gently wafted 

 into the gate way and lodged there, so as to 

 prevent the gate from shutting quite close. — 

 These tide g.ites were hung on hinges, either 

 perpendicularly or horizontally, and it was found 

 dilBcnlt to have them kept in snch exact order 

 as to exclude a slow tide. These, and other 

 evils attending the old tide gates, are complete- 

 ly removed by the new invented Tide Trunk, 

 which is perfectly firm, and closed merely by 

 the act of the water's rising to a given point, 

 without the least current whatever. 



A Tide Trunk is a wooden oblong vessel, or 

 square pipe, like a chest, open at the end next 

 to the sen, river, or other water, which it is 

 wished to shut out of the marsh, but closed at 

 the end next to the marsh. At the closed end 

 is a hole in the top. Beneath this hole, inside 

 of the trunk, or chest, is placed a valve, con- 

 sisting of light wood, which lies on the bottom, 

 unless it is caused to float by the water flowing 

 into the open end of the trunk, when it rises 

 and shuts the hole at Ihe top of the trunk. To 

 Ihe top of this valve is fixed a smaH iron rod, 

 which rising pcrp'^ndicularly, passes through a 

 frame consisting' of tivo upright pieces attached 

 io the opposite sides of the trunk, iuid two cross 

 pieces friined into the upright pieces in such a 

 uiannc''' 'hat holes may be bored in them thro' 

 ivbi'ch the iron rod may slide up and down frce- 

 ly, and be kept in a perpendicular position, and 

 thus keep the valve in its proper position, un- 

 der the aperture of the trunk. The iron rod 

 must be allowed to play with perfect ease thro' 

 the frame, and be so ligiit as not to prevent the 

 valve from floating; and if there be any appre- 

 lien«Ion of its sinking the valve, the under sur- 

 face of the valve may be coated with cork, to 

 make it sufficiently buoyant to rise with the 

 rod. There are other methods, which some 

 prefer to keep the valve in its proper position, 

 such as having perpendicular rods to pass thro' 

 the top of the trunk in such a manner as to con- 

 tine the valve to its place ; or having slips of 

 boards nailed perpendicularly on the inside of 

 the trunk, in such manner as to give the mo- 

 tions of the valve the requisite direction. The 

 vipper surface of the valve must be smooth, and 

 made to fit closely the under surface of the top 

 of the trunk round the aperture or bole through 

 which the water is admitted, as it drains from 

 the marsh. The valve should be allowed to 



move freely in the trunk, and yet be so large I to a degree of flatness, the greater will be the 

 as entirely to close the aperture, in whatever firmness and durability of the structure In dif 

 way it may float up to it. Mr. Johnstone ap- ficult cases, it is advisable, that the surface next 

 pears to entertain an opinion that a less com- the water should form an angle to a perpendi- 

 cular line, of from forty to sixty dee-rees ar. 



plicated apparatus might answer the purpose of 

 excluding the water of the tide from the trunk, 

 and merely directs that the trunk have a proper 

 flood-gate, or valve, fixed to the mouth of it, by 

 hinges on the upper side. 



As the water proposed to be drained of!" must 

 flow over the top of the trunk, and descend into 

 the aperture ; and as it is important that the 

 marsh should be drained as nearly down to low 

 water mark as possible, the trunk, whatever 

 may be its depth or width, should not be placed, 

 with the interior surface of its top more thsn 

 six inches above the ordinary low water mark; 

 because there should be room for the water, 

 pouring into the aperture t>om the marsh to 

 clear itself over the vnlve. The height from 

 low water mark to the top of the trunk, being 

 so much deducted from the depth to which the 

 marsh can be drained by the trunk ; it should 

 therefore, to pass the greatest quantity of water, 

 be made broad in proportion to its depth, so as 

 to allow of a large aperture, and to be placed as 

 low as is compatible with its object and utility. 



If one trunk should not be adequate to the 

 necessary draining, two or more may be inserted 

 — and as the tides are very irregular, it might 

 be well to place one trunk lower down, on a 

 level with uncommonly low tides, so as to take 

 advantage of the greatest degree of draining, 

 which such tides would aflbrd. At the mouth 

 of each trunk, it may be well to drive down 

 stakes in such a manner as to prevent the en- 

 trance of leaves, chips, and other substances, 

 which might impede the operation of the valve. 



Mr. Johnstone in his tract upon embankments 

 directs " to ascertain the exact height of the 

 highest flood-tides, so that the embankment be 

 raised at least two feet above what these mav 

 ever approach to. When this is done, the level 



rty to sixty degrees, ac 

 cording to the force to be opposed, and the na- 

 ture of the materials of which the mound or 

 bank is to be constructed. Where the founda- 

 tion is Arm and solid, the natural earth of the 

 ground, where it is erected, may be employed, 

 and will answer for the body of the bank, and 

 for the inner surface, and where the pressure 

 or force of the water is not very violent, the 

 slope next to it may be formed of the same ma- 

 terials. But in cases where the force of the 

 waves, by exposure to strong winds, operates 

 more violently against the bank, the outer slope 

 should be formed to the depth of two feet, with 

 cl.ay, or the strongest earth that can be conve- 

 niently got ; and that, as well as the top, cov- 

 ered with well swarded turf The inner slope, 

 or t lat next the field or marsh to be reclaimed, 

 shoild be sown with grass seeds. 



Mr. Johnstone says that " The stuff for form- 

 ing the bank, should be mostly taken from the 

 sid( next the water, that as little of the surface 

 witUn may be broken as possible ; only by what 

 is trken from the back cut or drain, tliat is nec- 

 essay, along the embankment on that side." — 

 An /.merican writer, however, advises in bank- 

 ing igainst a river or creek, to leave " a sufli- 

 cien space between the edge of the river or 

 creek, and bank,'' and to " form the bank by 

 earti taken altogether from within it.'"* Mr. 

 Johistone, however, in advising to take the 

 stuff to form the bank from the side next to the 

 watir is giving directions for embanking against 

 the ica, and the American writer has reference 

 to pcventing the encroachment of water from 

 a ri er or creek. We shall leave this question 

 to bi decided by professional engineers, ob- 

 servng, that all writers on this subject agree 

 that the earth of which the embankment is 

 composed, should not be dug out very near 



must be taken, and stakes fixed to the proper ,„ ;, u.,* „ ,; i ui „ ° i i , -^ . ., 



' . .r h ito it, t)ut a considerable margin shou d be left 



be embanked ■ - - " "• 



height along the whole line to 

 Two frames of wood, of the exact form of the 

 bank, should be made, and set up at the distanc 

 of twenty or thirty feet from each other, e.rnctij 

 on the same level, to guide and direct the heigit 

 and dimensions of its construction, and the sane 

 level must be kept throughout the whole liie. 

 This is more requisite than in the case of rivirs 

 that have a descent in their current, and whtre 

 the height of the water is regulated by the hll 

 of the stream ; for the surface of the sea water, 

 being all on a level, the top of the embankment 

 requires to be exactly parallel with the horizon, 

 without a rise or declension in any part." 



As the pressure of the water upon an em- 

 bankment against the tide, is different from that 

 agfiinst the current of a river, it is not necessary 

 to have it so straight, or of that uniform smooth- 

 ness which is requisite where a running stream 

 is to glide along the side of it. Where the em- 

 bankment crosses any creeks or hollows, it will 

 be necessary to increase the width of the base 

 in proportion to the depth. 



In forming the bank, the breadth, height, and 

 strength must be made in proportion to the depth 

 and weight of the water it may have to resist ; 

 taking into consideration the exposure to winds 

 and the rapidity of the motion of the tide. As 

 has been before observed, in substance, the 

 more the slope towards tUe water approaches 



between the excavation formed by digging out 

 the earth, and the mound or embankment which 

 is formed by such earth. 



No stones should be left near the foot of the 

 embankment ; for the tide forming eddies round 

 them, would soon make holes and break throuo-h 

 the bank. "^ 



Embankments of the kind under consideration 

 are liable to be destroyed by the waves, as- 

 cending the inclined plane next to the sea, and, 

 «hen the tide ebbs, returning with force, and 

 vashing away materials with which the bank is 

 cimposed. Covering the bank with turf, as be- 

 fre recommended may in many cases answer 

 t e purpose. As a further security, in situations 

 ct great exposure, the most efl'ectual protection 

 iilo drive piles in front of the bank, to break 

 tie force of the waves. An English engineer, 

 M. Beatson, says, " some years ago, when I was 

 01 duty as an engineer at a fort near Ports- 

 muth, built on a point of land much exposed 

 totlie sea, the waves made such havoc, that the 

 wlls on that side were constantly giving away, 

 al/iough built in a most substantial manner, and 

 h^ing bulwarks of large heavy stones besides, 

 toprotect the foundation : however all would 

 nc do, these bulwarks were soon knocked to 

 pices, and several times the wall itself At 



American Tarmer, vol. ii, p. 131. 



