The first object is to prevent the landing of any force for the purposes above stated between the Rigolets and the bay of Mobile; the second, to defeat that force in case it should be landed.  When the distance from one point to the other is considered, it is believed that it would be impossible to establish works so near to each other as to prevent the landing of such a force.  Its defeat, therefore, should be effectually provided for.  If the arrangement should be such as to make that result evident, it ought to be fairly concluded that the attempt would not be made, and thus we should accomplish in the best mode possible and with the least expense the complete security of this important part of our Union, the great object of our system of defense for the whole.

There are some other views of this subject which it is thought will merit particular attention in deciding the point in question.  Not being able to establish a chain of posts, at least for the present, along the whole coast from the Rigolets to Dauphine Island, or on all the islands between them, at which point shall we begin?  Should an attack on the city be anticipated, it can not be doubted that an adequate force would immediately be ordered there for its defense.  If the enemy should despair of making an impression on the works near the town, it may be presumed that they would promptly decide to make the attempt in the manner and in the line above suggested between the Rigolets and the bay of Mobile.  It will be obvious that the nearer the fortification is erected to the Rigolets with a view to this object, should it be on Cat or Ship Island, for example, the wider would the passage be left open between that work and the bay of Mobile for such an enterprise.  The main army, being drawn to New Orleans, would be ready to meet such an attempt near the Rigolets or at any other point not distant from the city.  It is probable, therefore, that the enemy, profiting of a fair wind, would make his attempt at the greatest distance compatible with his object from that point, and at the bay of Mobile should there not be works there of sufficient strength to prevent it.  Should, however, strong works be erected there, such as were sufficient not only for their own defense against any attack which might be made on them, but to hold a force connected with that which might be drawn from the neighboring country, capable of cooperating with the force at the city, and which would doubtless be ordered to those works in the event of war, it would be dangerous for the invading force to land anywhere between the Rigolets and the bay of Mobile and to pass toward the Mississippi above the city, lest such a body might be thrown in its rear as to cut off its retreat.  These considerations show the great advantage of establishing at the mouth of the bay of Mobile very strong works, such as would be adequate to all the purposes suggested.