Ring 2 is secured by screws b to upright 1 which has slots a for this purpose. Ring 2 can be set to any position along slots a to obtain the required coordinate x which is equal to A͞0 where 0 is the centre of ring 2. Rotating about fixed axis A is slider 3 which moves along groove d-d of disk 5. Slider 4, designed as a ring encircling fixed ring 2, has extensions c that fit in groove f-f of disk 5. The axes of grooves d-d and f-f are perpendicular to each other. When slider 3 rotates about axis A, a pencil clamped on upright 1 describes an ellipse on disk 5 which rotates about axis A and slides along the axes of its grooves d-d and f f . The size of the ellipse depends upon the preset distance x.
$1059$LG,Ge$