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rs <br />CURVE TABLES. <br />Published by KEUFFEL & ESSER CO. <br />HOW TO USE CURVE TABLES. <br />Table I. contains Tangents and Externals to a 1° curve. Tan. and <br />Ext. to any other radius may be 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 about 12 ft. Angle <br />of Intersection or 1.,P.=23' 20' to the R. at Station <br />542--x-72. <br />Ext. in Tab. 4 opposite 23,° 20',=120.87 <br />:120.87 =12 =10.97. Say a 10° Curve. <br />Tan. in Tab. I opp. 23° 20'=1183.1 <br />' 1183.1=10=118.31. ' <br />y , Correction for A. 23° 20' for a 10° Cur.=0.16 <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 />i' 2°.192'=def. forsta.- 542 1. P.=sta. . 542+72 <br />$° 492' _ " `� " 1 50 Tan. = 1 .18.47 <br />7° 19Z'= a rc u 543 <br />7 B. 1C. =sta. 541+53.53 <br />9° 492'= u u -{-50 <br />110 543 } L. C. = 2 .33.33 <br />86.86 E. C. =Sta. 543 -86.86 <br />104-53.53-16.47X3'(def. for 1 ft. of 10° Cur.) = 139.41'= <br />J 2 19a' =def. for sta. 542. <br />Def. for 50 ft. =2° 30' for a 10° Curve. <br />f Def. for 36.86 ft. =1° 50a'.for a 10° Curve. <br />