The planet Mercury.
--On Thursday night, the 20th ult., this planet attained its greatest Eastern elongation from the sun, with a more northerly declination of eight or nine degrees; it was therefore in an uncommonly favorable position for observation; indeed, in the
Northern hemisphere, the most favorable in 1861, except during its transit or passage over the sun on the 12th of Novembernext, which phenomenon will not, however, be visible in
America.
During last week, and early in March, the planet will set an hour and a half after the sun, and at 6 50m. P. M., will appear in the
West by South, or a little South of West, at an altitude of 10 degrees, as a reddish star of the first magnitude.