On the morning of the 12th, at daylight, we discovered that the enemy had thrown up a breastwork upon the sand, about one hundred and fifty yards to the north-east of the cuartel, and entirely commanding our watering place. We fired several round shot at it, with little effect. We succeeded in getting in being in strong force, and kept a close watch upon us. Their force was over three hundred, speaking within bounds. I immediately commenced digging a well in the rear of Mott's house, which is the lowest ground. I found that we had to go through rock, and judged we should have to dig about twenty feet. I thought it imprudent to blast, as the enemy, suspecting our intention, would throw every obstacle in our way. The men worked cheerfully on this and the succeeding day against all difficulties. Our situation was becoming now an imminently critical one, having with the greatest economy but four days' water. On the 14th we continued digging for water. We found that the enemy had thrown up a second breastwork more to the westward, giving them a cross-fire upon our watering place: there was a continual fire kept up upon the cuartel during the day. At three o'clock, 30 minutes P.M., a sail was reported in sight, which proved to be the United Ship Cyane. She anchored after sundown. It was of course a joyful sight to us to see friends so near; but I was apprehensive that they could render us but little assistance, the enemy being so vastly superior in numbers. The enemy continued their firing upon us during the night. On the 15th at day-light, we became aware that the Cyane was landing men. They soon commenced their advance, which for a few moments was opposed only by a scattering fire; then the enemy opened upon them in earnest. They had concentrated nearly their entire force near San Vincente. We saw the flash of musketry through all the hills above the village. There was the odds of three to one against our friends. Steadily they came on, giving back the enemy's fire as they advanced. There was still a party of the enemy occupying the town, firing upon us. I took thirty men, and sallied out upon them, drove them from cover, killed one and wounded several of them, and marched out to join the Cyane's men, who, with Captain Dupont at their head, had now drawn quite near to us. There were small detached parties of the enemy still hovering about them, and firing at them, but the main body of the enemy had been broken, and retired to "Las Animas," distant two miles. The march of the Cyane's men to our relief, through an enemy so vastly their superior in numbers, well mounted and possessing every advantage in knowledge of the ground, was certainly an intrepid exploit, as creditably performed as it was skilfully and boldly planned, and reflects the greatest honor on all concerned. It resulted most fortunately for us in our harassed situation. They had but four wounded; this cannot be termed any thing but the most remarkably good