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CURVETABLES <br />PubliAed,by KEUFFEL & ESSER-CO.. <br />HOW JO- 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 theTan. <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 giveri'External. <br />To find Nat. Tan. and Nat. 'Ex. Sec. for any angle by Table'L: Tan. <br />or Ext. of twice the given angle divided by the radius of a'1_7 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 I. P.=23* 20' to: the R. at' Station <br />542+72. <br />Ext. in Tab. I opposite 230 201--120.87 <br />120.87=12=10.07.. Say a 10° Curve. <br />'Tan. in Tab. I opp. 23° 20'= 1183.1 <br />1183.1 :-10 =118.31. <br />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 />2°192'=def. forsta.542 I.P.=sta. 542+72 <br />4° 4912'= " +50 Tan. = 1 .18.47 <br />70 1921= u aa" 543 <br />9°.49.2.= a as s' +50 B. C.=sta. `; 541+53:53 . <br />" it 543+ L.C.= 2..33.33 <br />11°40'= <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° 192.'=def, for sta. 542. <br />Def. for 50 ft. =2° 30' for a 10' Curve. <br />Def. for 36.86 ft. =1° 502' for a 10° Curve. <br />x) <br />