The long surges of the Gulf of Mexico were beating heavily upon the sandy beach of Point Isabel, but the dull and boding sounds were not the roar of the surf. There came a long silence, and then another boom. Each in succession entered the white tents of the American army on the upland, carrying with it a message of especial importance to all who were within. It was also of more importance to the whole world than any man who heard it could then have imagined. It spoke to the sentries at their posts, and compelled them to turn and listen. It halted all patrolling and scouting parties, making them stand still to utter sudden exclamations. More than one mounted officer reined in his horse to hear, and then wheeled to spur away toward the tent of General Zachary Taylor, commanding the forces of the United States upon the Rio Grande.