ELONGATION OF MERCURY.—The easterly elongations of Mercury in spring are the most convenient and favourable of the year for observing this planet. They occur in 1929 on Jan. 22 and May 15, and the former will afford some excellent opportunities for viewing the planet from about Jan. 14 until Jan. 28. On Jan. 16 Mercury will set about 1¼ hr. after the sun, on Jan. 26 about 1¾ hr. later. It will be brighter before the date of elongation than afterwards, so that observations should be attempted during the third week of the month. It will be moving in an easterly direction amongst the southern stars, but at the close of January will appear stationary in the western region of Aquarius.