midnight
At the first overt act of resistance , let them give the word to fire . After that , leave everything to the military . '' `` Quite so , your Excellency . '' `` Be careful to keep yourself in touch with me until midnight to-morrow . It may be necessary to declare a state of siege , and in that event the royal decree will have to be obtained without delay . Prepare your own staff for a general order . Ask for the use of the cannon of St. Angelo as a signal , and let it be understood that if the gun is fired to-morrow night , every gate of the city is to be closed , every outward train is to be stopped , and every telegraph office is to be put under control .