Form a plane passing through the north and south poles with its longitude right between J1 and J2. Then the line passing through (J1, W1) and (J2,W1) is perpendicular to the plane. The line passing through (J1, W2) and (J2, W2) is also perpendicular to the plane. Thus the two lines are parallel and therefore the four points lie in a plane.

Then we see that the four points form a symmetric trapezoid and hence they lie in a circle.