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Differences are ever to be cautiouslyweighed and considered, for they occasiona different Method of Scrutiny and Exami-nation, as well as a different Method of work-ing ; nor can we borrow any Light from ourNeighbours into this Affair, the Picture muff;absolutely be takenfrqm the Original; there-fore if any Authorfnouldattempt to writea Treatise of this Art, and describe the par-ticular Method of working which ought tobe pursued in a particular County or Soil,before he can pretend to render such anUndertaking compleat and beneficial to theInhabitants and Proficients of the Place hedesigns it for ; he must: survey the mineralMountains very carefully, that he may beable to compose his Geographia Subter -ranea in a correct and skilful Manner ; forif this is not done, how can he be supposedto form his Maps exactly true? How willhe be able to describe the labouring Part ?How will he be capable of distinguishingthe promising Symptoms from those thatare otherwise ? How will he manifest theSufficiency and Deficiency of the Produceof the Mountains, and point out the Wayby which they may be worked to the bestAdvantage ? Yet all these things must bediligently observed, and punctually prose-cuted ; ’ these Rules must be strictly obeyedand pursued by every Writer that designshis Labour to Benefit the Nation, to servethe Proprietor, and to instruct the Igno-rant.