are five houses immediately in front of the proposed battery, but upon a personal examination of the ground I find there are a dozen or more. These buildings are small and of wood, but they are occupied by a number of persons, probably forty or fifty. At the foot of the bluff, and immediately in front of the proposed battery, is a large brick building, not very high, and used, as I am told, as a store-house or ware-house. These buildings, with the exception of the latter, must all be removed before the battery is used, or they will be destroyed the first time the battery opens. The projectiles, however, will pass over the ware-house, but as the distance from it is but 500 feet, it becomes a question whether or not it will be injured or destroyed by the discharge. The battery when erected must be used for practice, even if no enemy should appear. The large high brick building used as a hospital is to the left of the battery, but it is also 200 yards in advance of it, and therefore to preserve this buildings no shot can be directed to the left of Yerba Buena Island. This, however, though a disadvantage, may be considered of not much importance. Thinking it possible that the necessity for removing the buildings referred to, if the proposed locality of the battery is not already decided upon, may be sufficient cause for at least an examination, before a final decision, to see if any other locality for the battery can serve the end in view, and at the same time obviate the necessity of removing so many persons from their homes, I have made an examination of the vicinity of Steam-Boat Point, and find that there are several localities suitable for batteries and which are not occupied by or in front of dwellings, and where a more extended field of fire can be obtained, but they are more distant from the proposed works on Yerba Buena Island by from 500 to 800 yards. One, I may mention, is on Second street, just below Brannan street, where there is a nearly horizontal piece of ground, nearly or quite as long as the locality on Beale street, and directly on the bluff, the direction of which there is nearly at right angles with a line to Yerba Buena. The bluff there is about thirty feet above low-water mark, according to the Coast Survey. Another suitable locality, but of a different character, is on or near the summit of a hill back of the locality just described. The hill in its highest point is 111 feet above low-water mark. A battery of three or four guns (or more if desired) can easily be located there in a very commanding position. I respectfully submit that, in my opinion and in the absence of Colonel De Russy, the subject of a change in the proposed position of the battery is one of sufficient importance to suggest a personal examination of the vicinity by the commanding general of the division. With regard to the batteries on Yerba Buena Island, the party must either return to the city every night or suitable messing arrangements and shelter must be provided for them. As transportation must be furnished for the material, &c., necessary for the work, it is probable the purchase or charter of a suitable steam-boat will prove in the end the cheaper, and obviate the necessity of building shelters for the men. On account of the rocky nature of the island the work will necessarily progress slowly. I propose to make a personal inspection of the island in a day or tow. I beg leave also to be informed when the necessary funds for this work will be furnished, and their amount.

I have the honor to be, very respectfully, your obedient servant,

R. S. WILLIAMSON.

Captain, U. S. Engineers.

P. S. - In order that you may understand the position of the points I have referred to, I return you the maps of Colonel De Russy, and also