. The railroad and engineering journal . Fig- 245- • Students who wish to study this subject still further are advised to re?d THE ELLIPSE. An ellipse is an oval-shaped curve, fig. 247, which has thecharacteristic property that the sum of the distances of anypoint in the curve from two points, a and b, called the foci, is The Field Practice of Laying out Circular Curves for Railroads, by Johng. Trautwine, Vol. LXV, No. 5.] ENGINEERING JOURNAL. 2^ TABLE OF UADII—CIIOKD, OlfE FOOT. (ConUntied.). Fig. 247. equal to the long diameter, C D, called the majoror conjugate axis. Thus, in fig. 247,
. The railroad and engineering journal . Fig- 245- • Students who wish to study this subject still further are advised to re?d THE ELLIPSE. An ellipse is an oval-shaped curve, fig. 247, which has thecharacteristic property that the sum of the distances of anypoint in the curve from two points, a and b, called the foci, is The Field Practice of Laying out Circular Curves for Railroads, by Johng. Trautwine, Vol. LXV, No. 5.] ENGINEERING JOURNAL. 2^ TABLE OF UADII—CIIOKD, OlfE FOOT. (ConUntied.). Fig. 247. equal to the long diameter, C D, called the majoror conjugate axis. Thus, in fig. 247, the distancea f -(- f i = C A and a <• + * = C /). If wemeasure the distance of any point of the curvefrom the two foci, and add these distances to-gether, their sum will be equal to the majoraxis. Ellipses also have the peculiarity that the nearertheir two axes are of the same length, the morethe curve approximates to a circle, and it willcoincide with a circle if the axes are of equallength ; on the other hand, if Che minor axis isshortened in proportion to the major axis, thelength of the figure will approximate to a straightline, and will become such a line if the short di-ameter is infinitely small. Ellipses may, there-fore, be round or flat, but they always have theproperties described above. Problem 69. To draw an ellipse with a stringand pencil. Lay down the major axis CD, fig. 247, and bi-sect it at E, and draw the minor axis c ^throughE and perpendicular to C D. To find the
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectrailroa, bookyear1887
