1838] 



FARMERS' REGISTER. 



71S^ 



merit from Its first posilinn, and oautionin<]f the man 

 to fix the siijht to the staff at the point directed, he 

 may proceed lorty or fil'ty yards farther ; and aller 

 havinj; again adjusted the level, make a siijn to 

 him to move to higher or lower ground, till the 

 eiglit on the staff again coincide with the cross 

 hair in the telescope. He may then leave a peir 

 at the place where he held the staff, and proceed 

 in like manner to other stations, till the whole line 

 is finished, leaving pegs, or making pits, at the 

 places where the staff' was held. 



If the length of the line to be levelled req.n'res 

 the instrument to he shifted from its first position, 

 the level must ajjain be taken from the last station 

 where the staff' was held, and the sight on it fixed 

 in the pro[)er place, as before directed, proceeding 

 in the same manner at every forty or fifty yards, 

 till the who'e is accomplished. After the line is 

 thus levelled, and ascertained by marks left at 

 every station where the staff was fixed, it may 

 acrain be examined, and other pegs put in between 

 those first placed, the better to direct the work- 

 men m cutting the drain ; giving the line such al- 

 teration from the course of the level, as may 

 shorten or siraiirhten it, according to the nature 

 and situation of the ground. 



For the sake of accuracy, where the work re- 

 quires it, especially if the water is to be conveyed 

 a considerable distance, or wanted to supply a 

 house, or for the purpose of irrigation, the levels 

 may be proved by reversing the former line of di- 

 rection. The spirit-level is also useful for ascer- 

 taining how much fall can be obtained from the 

 drain to the nearest outlet where the water can be 

 discharged; the shorter that distance is, the better, 

 provided fall enough can be got. 



It is often necessary to level a much longer dis- 

 tnce than the length of the drain may require to 

 be cut; but when the level of the whole line is 

 known, and the nature of the ground carefully ex- 

 amined, a shorter Ime of drain may effect the pur- 

 pose ; as will be judged of by circumstances that 

 may be discovered in the course of cutting. 



There is a triangular wooden instrument, in 

 form of a mason's plumb, called the American 

 level, which has been used in ascertaining lines 

 on the surface, for the purpose of conducting 

 drains or water-courses on a level ; but as it has 

 never been used in this country, and is very in- 

 ferior in point of accuracy to the spirit-level, it de- 

 serves no particular description. 'When the line 

 or lines of a drain nfe marked out in the field, it is 

 useful to make a sketch of both, with the dimen- 

 sions and levels marked at the various points, the 

 better to preserve their exact direction, in citse of 

 their not being executed immediately ; or the su- 

 perintendence of their execution left to a different 

 person than the one who marked them our. This 

 is also uselijl in finding the lines afterwards, when 

 it may be nec(!ssary to ascertain them. 



PART III. 



SECTION I. 



Of the varidils modes of forming and filling 

 drains, and their duration. 



There is only one effectual mode of forming and 

 filling drains, intended for the purpose of cutting 

 off and conducting springs, and that has already 

 Vol. V— 90 



been described The depth, in that case, depends 

 on that at which the stratum containing the water 

 lies; the width at top must be in proportion to 

 that depth; and the width at bottom nmst con- 

 form to the size of the conduit that is requisite, 

 which is regulated by the ijuantity of water it has 

 to convey. In short, tiie size of a drain, in point 

 of width, should lie no more than to give room lor 

 the men to work, unless when the soil is so soft 

 and loose, that a greater siupe is necessary, to pre- 

 vent its closing or coming together ; for an over 

 width only increases the expense of digging, and 

 also the quantity of materials used in filling, which 

 is in many situations an object of economical con- 

 sideration. Stone and brick are the most durable 

 materials, where they can be had at a reasonable 

 expense ; but other substitutes have been found to' 

 answer well, where neither of the former can be 

 easily procured. Stones are used in three ways: 

 formmg a square conduit ; coupled, or set on end, 

 so as to form a triangular opening; or thrown in 

 promiscuously, which should never be done, if 

 stones large enough can he got for boxing, or 

 coupling below. The common brick, or those 

 made on purpose, are perhaps preferable to stone, 

 iri respect that they can be more quickly and uni- 

 formly laid, and give less interruption to water 

 than the ragged edges of stone. Whether stone 

 or brick is used in forming the box or conduit, 

 there should always be as many small stones above, 

 the cover as to close the interstices before the turf. 

 is laid on, and the other stuff is thrown in, part of 

 which might otherwise find its way into the water- 

 course, and injure or choke it up. 'Wood, particu- 

 larly old thorris, is next best to these, and when 

 cut into billets, and laid in the manner represented 

 in the plate, is found to answer remarkably well, 

 particularly in soft or peaty soils, where the weight 

 and pressure of stones would be apt to make them 

 sink. 



In clay soils, where the sides are solid, and not 

 apt to crumble down, and where the quantity of 

 water may ne small, straw, loose or twisted inlof 

 ropes, has been used. It leaves a sufficient open- 

 ing for the water to flow through, and when the 

 straw decays, the clay has formed an arch over it,' 

 capable of" supporting the incumbent soil, and 

 leaving a clear passage for the water below. But 

 to resist the pressure of horses or cattle, in the act 

 of ploughing, the depth must be sufficient to' 

 allow a prober quantity of earth above. Tlie' 

 effect of every perishable material depends on this,< 

 and therefore the depth should be accordingly. 

 Heath, furze, or broom, may be employed for the'^ 

 same purpose ; and in all these cases, the bottoiir 

 may be very narrow (not exceeding a foot), whicji 

 greatly lessens the expense of digging, and saves" 

 both material and labor in filling. 



The sod or pipe drains are undoubtedly m€ 

 least expensive of any, and may be of considera!- 

 ble benefit in some soils, particularly in pasture? f 

 but their duration, and safety in tillage grounds,- 

 cannot be much depended on, unless, as in the' 

 last-mentioned cases, the openin'g is at a consider- 

 able distance from the surface, and wl^en the 

 mould that covers it becomes incrusted over the' 

 sod. The method of executing them is, by dig- 

 ging a trench of a proper width, and of a depth 

 not less than three feet ; and then, taking out the 

 last portion with the narrow under-dyainmg spade, 

 a shoulder is left on each side, upoti which a sod' 



