38 



FAR iM E US' R E (; I S T E R. 



[No. 1 



a.-e firsi i()o^ipne(t and carried down, and the wa- 

 ter sirikinir vvilh velocity on \\\e whole f.ice, ol' the 

 dike, ui-ei'ipitiues it.<eir wilh violem-e aLiHinsi those 

 at ti;e h)tfo:n, an 1 disp a:uiij| ihein, the whole 

 slrui'U re is s^ioii deinoliHtie.l. 



I)a'ii:s, that are otecied at a sfill ^rre dnr ex- 

 penr^e, ofhiMvn sion^, hut of asiinilar ooiirstruction, 

 are al.^o liibieto h". dois:royed (ahhono-ii in a [es- 

 ser degre,"), it' the lower side is tbravd with a 

 slope, or incliripd ph^ae. The wa^er, in ihi^ cnss, 

 does not inr^iiiLiaie itsell in such a l)ody anQoiij; 

 the stont^s ihai ace joined, as it does wlien tfieyare 

 loo-seiv inid loreiher. as ;n (he first meniioiieci base; 

 bii sill', the llirre o!' the fiilliniT water iias such 

 eh''!'!'' iinori the iruli'mMst layers ot" stone, tiiat in 

 time it canno: (iiil to iimlertniiie and (hsplace them. 

 'I'he (irst error in n!| ihes«^ kinds of stotie-wears, is 

 tile carrvinir rheni in a straight line across the riv- 

 er or stream. TiU'V should he const riicted so as 

 to in an ar.'h across the hed of the stream, with 

 the convex side upwards, the end<! resting on 

 siron;' atiutments placed in the bank on both 

 pides. By this :nea;is the. force of any body of 

 water, however urre.it, will be effectually resist- 

 ed, and ihe strncinre be perfectlv firm and secure. 

 Tlie urreater the slope towards the upper side, the 

 betier, hut ilie lower'' side sho'.ild be nearly ner- 

 pendicnlar, that the water may Iiil i over it like a 

 cascade, without cominsr in contact with \he lace 

 of the builniiiir. Fiirs. 2 and 3, of Plate V'. are a 

 piati and section of this. Darn-dikes, of the con- 

 sirnciion first mentioned, are someiimes secured 

 by beams of woo(], Ibrniinif a kind o[' ii-anie-work, 

 in which the stones are placed, But this is liable 

 to accidents, by the wood rottiiitr and ofivins; wtij-; 

 consequently the stones lose their hoid, and are 

 soon separated and displaced. 



In biiildinjj the dike or wall, as represented by 

 Fiif. 3 in the Plate, it is necessary to diii; till a firm 

 IbunJiUion he i()iind. The lieisht will be regula- 

 ted as circumstance? direct, and the breadth ol' 

 the jliundation must be according/ to that height. 

 If the heiirht be twelve feet, the breadth at the 

 foundation may be six, and at lop, two feet. The 

 stones should be bediied with as much care as pos- 

 sible, Hnd the joints closely cemented with mortar 

 or tarra>i, fliat no water may escape, and that the 

 biiildiiiij may be firm and durable. When the 

 wall reaches the requisite heitrht, if, should be ex- 

 at;tly lev(;l across ih?. whole length of the stream, 

 that the water may spread over the whole, of an 

 equal thickness, and so moderate its force in time 

 of a flood; and upon the top, ihere should be a 

 coping ol' Hat stones, neatly cut find jointed, pro- 

 jectiiiiT nearly a foot over the perpendicular wall 

 on the under side, with a rise of a few inches to- 

 wards the upper side. The length of these stones 

 will require to be three feet; but, if such are d;fii- 

 cult to be got, planks of oak, or larch v*ood, may 

 be used in their stead. That no water mny leak 

 ihrouga the buildinsr, it will be proper to iiave a 

 bed of clay, thr^-e or iburfiiet in thickness, along 

 the upper side of it, well beaten down, and that to 

 the whole height of the wail. The section of 

 clay should be founded lower than the breast- 

 work ol stone, to prevent the water escapinir un- 

 der it. The coping stones should be laid on clay 

 or tarrae, so that the upper part of the buildintr 

 may be perfectly water-tight, which is a material 

 object in operations of thi^ kind. Gravel, or any 

 loose rubbish, should be tumbled over into flie 



dam, above the clay, shelving gradually from the 

 dike into the water, so as to make the siope as long 

 and easy as possil)le. 



The use of the projection in the coping is to 

 throw the water cle.ir over, so as it may fall .it a 

 distance from the bottom of the buildinir. The 

 pavement ihere will prevent the water makinii an 

 impression, or openinj? a cavity in the bed of the 

 river, whereby ilie wail miiiiit be underminetl; and 

 il is necessary that this pavement shouki extend 

 solar as to be beyond reach oi' the iiill when the 

 stream is in flood. 



JFI^ads. or hanks oj earth, for the confinement of 

 water in artificial lakes or jionds, are often con- 

 structed at great expense, and nut being pro|;eily 

 formed, often break out. and occasion considerable 

 (bimage. The error in their construction is com- 

 monly owingto the want of breadth at the base, in 

 proportion to their height; and to their not having 

 a sutTicient sirjpe towards the water, nor a proper 

 section oC puddle iti the centre. 



Fig. 4, in the Plate No. V. is a representation 

 of what an embankment of this kind should be, 

 according to the supposed dej)th of water it may 

 have to supjjort. As this bank is acted upon by 

 the vAJ^ater, in a similar manner as tliatlbrthe con- 

 fining of lakes, as has been already described, its 

 degrees of slope should be the same, more or less, 

 according to tlie depth or shallowness of the wa- 

 ter. If in a park, or pleasure-ground, the out- 

 ward slope should also lie i^ieater than that of 

 any other embankment, that ii may connect moie 

 naturally with the adjoining' surlace, and have as 

 little appearance of art as possible; and shrubs, or 

 clumps of low trees, may be planted on it, to lessen 

 that ap[)earance. Mounds fijrthis purpose are com- 

 monly constructed across dens or hollows, where 

 that part of the water immediately above them 

 is of considerable depth. Where this is the case, 

 tmd the depth exceeds ten It^et, tlie breadth ai the 

 base of the embankment will require to be greater 

 in proportion than the section repiesenieii in the 

 plate; that is, if the depth is fitieen feet (which it 

 will seldom exceed), the laeadih at bottom should 

 be sixty feet; and at top, fifteen. The puddle will 

 require to be equally thick in proportion, and must 

 be sunk several feet deeper than the surface on 

 which the bank is founded, or till a stratum of 

 clay or other sale tbundation is got. The mound 

 shouid be formed of as solia materials as can be 

 (jot from the space to be occupied by the water; 

 and to render it the more compact, it should be 

 well beaten down, and consolidated in the course 

 of ils beinnf formed. 



Both sitles should be lined with turf, and the 

 water should not be admitted lor some months af- 

 ter the bank is com[;leted. For want of altending^ 

 to this, many heads have given way, by letting- 

 in the water, and filling the pond, before the earth 

 was sufHeiently consolidated; and it is very diffi- 

 cult to make up a breach m the bank afteirwards. 

 Where the artificial mound joins the natural banks, 

 a space should be dug out, to insert, as it were 

 the one into the other, to prevent the constant 

 pressure and agitation of the water at these points 

 from making a breach, and Ibrcing an outlet lliere. 

 A sluice, strongly secured by masoi>work. should 

 be placed in the most convenient part of the bank, 

 to let out the water when necessary; and an over- 

 fall, for the waste water, will also he requisite, 

 which ought to be parhcularly attended to. This 



