midnight
The river was running full of ice , which rendered crossing , especially by night , exceedingly perilous . To this was added the danger of being challenged , and it might be shot , by the sentries of the American camp . But when did true love in man or woman stop to calculate chances , or hesitate to encounter danger or even death for the beloved one ? It was on the 9th of December -- a bleak , cold , cloudy night -- that Mary , having secured the aid of her father 's faithful servant , Michael O'Brian , a jolly but rather stupid Irishman , who knew no fear , escaped through the window of her room after the family had retired to rest , which was not till near midnight , and set forth on her perilous mission of mercy . In order to avoid the American sentries they attempted to cross about a mile above the camp , and in the murky darkness , fearlessly launched their little boat , steering by the lights in the town , slumbering unconscious of its fate , where some patient watcher kept her vigil beside a sick bed . The dark water eddied and gurgled amid the ice-floes , from which a ghastly gleam was reflected , like that from the face of a corpse dimly seen amid the dark . Occasionally a huge fragment of ice would grate , and crash , and crunch against the frail ribs of the boat , as if eager to crush it and frustrate the generous purpose of its passengers .