Smith, G. / The laboratory; or, School of arts: containing a large collection of valuable secrets, experiments, and manual operations in arts and manufactures, highly useful to gilders, jewellers, enamellers, goldsmiths, dyers, cutlers, pewterers, joiners, japanners, book-binders, plasterers, artists, and to the workers in metals in general; and in plaster of paris, wood, ivory, bone, horn, and other materials
Part VI. Gnomonics; or, the art of dialling, pp. 109-126
IALIG PART V.L GNOMONICS; OR, THE ART OF DILLING. PROBLEM L to prepari the fwundamntal Quadrant for the erecting ofSan-dis. '"RAW the line a b~fig. 1. plate XIV; erect thereon a L.Iperpendicular, b c; froi b describe the arch a c, i ourth part of a cic, and containing ninety 4eges ThenMok for the e1~vation of the pole, or tlh ltu of the plae where the dial is designed for, which, for. exmmla, for London, is fifty-one degrees, thirty-two inutes ; subtract this from the ninety degrees, and there reugain thirty-eight. degrees, twenty-eight minutes. This done, divide the arch a c in three equal parts, each con- tainingthirty degrees. The part d e divide again into three parts, each containing ten degrees. These ten degrees di- %ide again in two, each coiAtaining five degrees, consequently from a tof thirty-five degrees. Divide f g in five single degrees.
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