Mercury stations retrograde on March 29, 1919 at 22° Aries, and direct on April 21 at 10° Aries — 23 days. From the Earth, Mercury seems to back up against the stars as we overtake it, as a car passed on the highway seems to slide backward. Astrology holds it a time for crossed wires and delays. Computed from JPL's approximate orbits; the stations agree with an almanac's to within minutes.