midnight
Even as he stood performing this pagan rite , there sounded afar off a dull , low boom like the distant report of heavy cannon . It echoed weirdly along the valley where all was quiet and at rest , and was three times repeated , like some ominous voice of warning . Omar heard it . Surely the noise was an unexpected one , for it instantly filled him with apprehension , and he listened attentively , little dreaming that I also was his companion upon this strange midnight vigil . THE low booming was , however , not repeated , and by this my companion apparently became reassured , for shortly afterwards he threw himself down near me to snatch a few hours ' repose before dawn . I suppose I , too , must have slept for some time , until suddenly a noise like thunder that seemed to cause the earth to tremble awakened me , and together with the rest of our party I sprang to my feet , fancying that some terrible earthquake had occurred . It was still dark , and as each asked breathlessly of his neighbour the cause of the deafening noise a sudden red flash showed for an instant on the summit of the rock near where I had seen the light , and a second report thundered forth , making the valley echo and startling the birds in thousands from their roosting-places .