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I ELD BOOK 514 ; <br /> CURVE TABLES. <br /> Published by KELJFFEL & ESSER CO. <br /> HOW TO USE CURVE TABLES. <br /> Table I. contains Tangents and Externals to a 1°curve. Tan.and <br /> f",Y a .�[/�o Ext.to any other radius maybe found nearly enough,bydividing theTan. <br /> o or Ext.opposite the given Central An le by the given degree of curve. <br /> $S To find Deg. of Curve, having the Central Angle and Tangent: <br /> -- Divide Tan.opposite the given Central An le 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 /> a i To find Nat.Tan.and Nat.Ex.Sec.for any angle by Table L:Tan. <br /> 7-- L _ ._._ 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 about 12 ft. Angle <br /> of Intersection or L' P.=230 20' to the R. at Station <br /> 542+72. <br /> - - - - - - Ext.in Tab. I o <br /> ' pposite 23°20'=120.87 • <br /> 120.87+12=10.07. Say a 100 Curve. <br /> Tan.in Tab. I opp.230 20'=1183.1 <br /> - --- <br /> 1183.1+10=118.31. <br /> Correction for A.230 20'for a 100 Cur.=0.16 j <br /> - -- - __ <br /> 118.31+0.16=118.47=corrected Tangent. <br /> (If corrected Ext.is required find in same way) <br /> Ang.23°20'=23.33 +10=2.3333=L.C. <br /> 2°19Y-def.for-sta. 542 I. P.=sta. 542+72 <br /> _ - — 40 49j'= a +50 Tan.= 1 ..18.47 <br /> 90 49+}'=a a a 543 B.C.=sta. 541+53.53 <br /> 110 40'= a a a �+ L.C.= 2 .33.33 <br /> 86.86 E. C.=Sta. 543+86.86 <br /> 100-53.53=46.47X3'(def.for 1 ft.of 10°Cur.)=139.41'= <br /> 2°191'=def.for sta.542. <br /> --- Def.for 50 ft.=20 30'for a 10°Curve. <br /> Def.for 36.86 ft.=10 50}'for a 100 Curve. <br /> ex , <br /> - - — - - -_ <br /> AAn .23'201 <br /> N <br /> IC•C¢rveI9 <br /> - - - -- \N. <br /> t i <br /> •., <br />