Snelling, Henry Hunt, 1816-1897 · [New York : W.B. Smith] · leaf 271
or touch it with the fingers, forthe slightest stain upon the surface will bea defect in the drawing. It is indispensa-ble that the last operation with the acid beperformed immediately before it is intend-ed for use. Let every particle of dust beremoved, by cleaning all the edges and theback also… … 31 blet near the corners; and the whole isretained in a proper position by means ofscrews, as represented at d d d d. Second Operation.—It is necessaryfor this operation, which is really the mostimportant of all, that a box, similar to figs.32 and 34, be provided. Figure 32 re-
Photography · Art and photography
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![An illustration from Vnderweysung der Messung : mit dem Zirkel vn[d] Richtscheyt in Linien, Ebnen vnnd gantzen Corporen (1525)](https://img.insideoutlibrary.com/img/200/ia-vnderweysungderm00drer-123-254.webp)
