Popular science monthly . 310 Popular Science Monthly Surveying Instrument. The tripod and sighting in-strument are constructed ofsimple materials TO make a practical surveying instru-ment, take a piece of tin or sheet-iron two ins. wide and sixteen ins. long;a piece of 7-8 in. wood shaped like atriangle, three ins. on a side; threestrips of wood as long as the distancefrom the ground to a little above youreyes when you are standing erect; onelath one foot long; and a wing-bolt. Bend up the strip of metal two each end so as to form right ]/i in. from the top of the b
Popular science monthly . 310 Popular Science Monthly Surveying Instrument. The tripod and sighting in-strument are constructed ofsimple materials TO make a practical surveying instru-ment, take a piece of tin or sheet-iron two ins. wide and sixteen ins. long;a piece of 7-8 in. wood shaped like atriangle, three ins. on a side; threestrips of wood as long as the distancefrom the ground to a little above youreyes when you are standing erect; onelath one foot long; and a wing-bolt. Bend up the strip of metal two each end so as to form right ]/i in. from the top of the bentportions and extending to }4 in. of thebottom, cut a slit >^ in. wide to sightthrough. Screw or nail the metal stripto the short lath. Drill a hole in themiddle of this apparatus to correspondwith the size of the wing-bolt, and onein the center of the triangle. Now make a tripod by hinging one ofthe three long strips to each side of thetriangle. Pnt a nail, with the head tiledoff, in the bottom of each leg to lormthree anchoring points. F To Re-Silver Old Mirrors i
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectscience, bookyear1872
