This head-quarters of the Vigilance Committee, San Francisco, is situated on Sacramento street… The breastwork… composed of sand bags… is about ten feet high, and is six feet wide. Behind it are planted cannon, in positions to rake all the approaches to the building. The Committees’ Rooms extend into the adjoining edifices, and on their tops sentries are posted and cannon mounted. On the top of the fort, a small piece of artillery is placed commanding the vacant square in front of the building.