COLUMNS, denominated from their use.—Astronomical COLUMN, is a kind of observatory, in form of a very high tower built hollow, and with a spiral ascent to an armillary sphere placed a-top for observing the motions of the heavenly bodies. Such is that of the Doric order erected at the Hotel de Soissons at Paris by Catharine de Medicis for the observations of Oronotius Fineus, a celebrated astronomer of that time.