20 FEBRUARY 1926, Page 19

WALKING IN CIRCLES [To the Editor of the SPJicTATOR.] Snt,—Your

many correspondents on this subject have over- looked the rotation of the earth as a factor in this question. Neglect the convexity of the Northern hemisphere, and treat it as a disc revolving round the pole as its centre, and the natural tendency of a body set in motion on its surface will be to swerve to the right (or.on the Southern hemisphere to the left). The free air in an anti-cyclone moves to the right round its axis, while a cyclonic disturbance takes the opposite course.

Another analogy is that of a free pendulum set swinging due •north and south, which will be found at the end of an hour to have swerved to the right—i.e., to N.E. and S.W.—