226 TREATISE on 



rarely anfwer any two fields of a hundred, and therefore, with-- 

 out getting a particular plan of every fpot, we get nothing, a ge- 

 nerally ufeful one being impradlicable. Nature muft ditlate the 

 courfes we are to follow, good fenfe purfae thofe didates, and^ 

 experience condudl the diffex^nt manners of operation,. 



Where double ditches are determined, the breadth of the" 

 bank between them muft be proportioned to what plantation 

 you there intend ; but in general they are made too narrow, . 

 from whence the bank becomes dry, and the plants of courfe 

 are not properly nouriihed. For a hedge only, the bank ought 

 to be nine feet at bottom, and eight at the top; for a hedge and 

 one line of trees, fixteen, that is, planting the trees at eight feet 

 from the hedge, and four from the edge of the bank ; and for 

 two lines of trees, one on each fide of the hedge, twenty-eight 

 feet. This I think is the meanefl allowance ought to be granted,; 

 but where what is commonly called ftripes of planting are rer 

 quired, either for the benefit of the wood, or the improvement 

 of the climate by fhelter, the plantation ought to be broader or 

 narrower as the inclofures they furround are greater or lefs, . 



Let the quality of the foil be confidered in the confl;ru<5lion 

 of ditches, and more bafe given to the perpendicular height, 

 where the land is loofe and fandy, or fpungy and mofiy, . than 

 where well tempered and folid, or obftinate clay and tilL, A 

 ditch, on foils of the latter qualities, four feet wide, will admit 

 of being the famxe depth ; of the former, three feet depth to the 

 fame breadth, will in general. be as much as it will bear, and fo 

 in proportion as the ditches are broader or narrower. In fpouty 

 and moffy foils the Sweet Briars will be doubly ufeful, as they 



