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CURVE TABLES. <br />Published by KEUFFEL & ESSER CO. <br />IffO`V TO USE .CURVE TABLES. <br />Table I. contains Tangents and Externals to a V curve. Tan, and <br />Ext, to any other radius maybe found nearly enough, by dividing the Tan. <br />or Ext. opposite the given:Central Angle by the given degree of curve. <br />To find Deg. of Curve, having the Central Angle and Tangent: <br />Divide Tan. opposite the given Central Angle by the given Tangent. <br />To find Deg. of Curve, having the Central Angle and External: <br />Divide Ext. opposite the given Central Angle by the given External. <br />To find Nat. Tan. and Nat. Ex. Sec. for any angle by Table I.: Tan. <br />or Ext. of twice. the given angle divided by the radius of a 1° curve will <br />be the Nat. Tan. or Nat. Ex. Sec. <br />EXAMPLE. <br />Wanted a Curve with an Ext. of abut 12 ft. Angle <br />o <br />of Intersection or I. P. =230 20' to the R. at Station <br />542+72. <br />Ext. in Tab. I opposite 23° 20, =120.87 <br />120.87=12.=10.07* Say a 10° Curve. <br />Tan. in Tab, l opp. 23°20'=1183.1 <br />1183.1=10=118.31._ <br />.,Correction for A. 23° 20' for a 10° Car. =0.16 <br />118.31+0.16,=118.47 =corrected Tangent. <br />(If corrected Ext. is.rtuired find in same way) <br />Ang. 23' 20'=23.33 --10=2.3333=1-.C. - <br />2° 191'=def. forsta.- 542„ I. P.=sta. 542+72 <br />40 49;' _ a « <br />I-50 Tan. 1 .18.47 <br />70 1911= a,< a <br />90 4911= « « g .+50 B. C. = sta. 541+53.53 <br />110 40' « « « ... 543+ L. C.= 2 .33.33 <br />86.86 E. C. = Sta.' 543+86.86 <br />100-53.53=46.47XT(def. for 1 ft: of 10° Cur.) 139.41' <br />2' 1912'=def. for sta. 542. <br />Def. for 50 ft. =2° 30' for a' 10° Curve. <br />Def: for 36.86 ft. =1° 50+}' for -a 10° Curve, <br />