Designed for the Use of the Locating Eigineer. Containing Tables of Actual Tangents, and Arcs Expressed in Chords of 100 Feet for Every Minute of Intersection, from 0 ̊to 90,̊ from a 1 ̊curve to a 10 ̊curve, Inclusive; Also Tables of Formulæ Applicable to Railroad Curves and the Location of Frogs. With Explanatory Problems