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`/ ✓ CURVE TABLES. <br /> __ `�``�1 ``�' �•� 3 <br /> 1-'147- Z`. 7 e.c K. Published by KEUFFEL ESSER CO. <br /> HOW TO USE CURVE TABLES. <br /> C•.. •_ 1 a t 9l Table I. contains Tangents and Externals to a 1°curve. Tan.and <br /> Ext.to any other radiusmay be found nearly enough,bydividing 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 ale by the given Tangent. <br /> To find Deg. of Curve, having the Central Angle and External: <br /> c7pDivide Ext. opposite the given Central Angle by the given External. <br /> /�- y�/V 7i .S �' To find Nat. .and Nat.Ex.See.for an angle b Table I.:Tan. <br /> -�"-- - ��svle Y g y <br /> Or Ext.of twice the given an le'divided b the radius of a P curve will be the Nat.Tah.or Nat.Ex.Sec. Y <br /> EXAMPLE. <br /> Wanted a Curve with an Ext. of about 12 ft. Angle <br /> of Intersection or I. P.=230 20' to the R. at Station <br /> v".G . UJ t 9 /'. v, 542+72. <br /> Ext.in Tab. I opposite 23°20'=120.87 3 1.7 <br /> - 120.87+12=10.07. Say a 10°Curve. <br /> —' 3 z,4 <br /> Tan.in Tab. I opp.23°20'=1183.1 p <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°19j'=def.for sta. 542 I.P.=sta. 542+72 <br /> 4049j'= " " " +50 Tan.= 1 .18.47 <br /> -_ 7019F= a a a 543 <br /> — <br /> 9049j'= a a a + B. C.=sta. 541+53.53 <br /> 11°40'= a a a 543+ 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.=2°30'for a 10°Curve. <br /> - Def.for 36.86 ft.=1°50j,'for a 10°Curve. <br /> - e* <br /> ax <br /> _ >r <br /> .P.Ang.23.20' <br /> N <br /> -._- - 10•Curve <br /> j <br /> FIELD B OK 457 <br /> ';,� <br /> j <br /> r <br />