Federal agencies will be closed and most employees will be excused from duty without charge to leave on Friday, December 26 under an executive order issued by President Bush. The order adds that agency heads “may determine that certain installations of their organizations, or parts thereof, must remain open and that certain employees must report for duty . . . for reasons of national security or defense or other public need.” The announcement follows the general practice of giving employees an additional day off to create a four-day weekend when Christmas Day falls on a Tuesday or a Thursday.