Mr. Eppes has this moment put into my hands your letter of yesterday, asking information on the subject of the gun-boats proposed to be built. I lose no time in communicating to you fully my whole views respecting them, premising a few words on the system of fortifications. Considering the harbors which, from their situation and importance, are entitled to defence, and the estimates we have seen of the fortifications planned for some of them, this system cannot be completed on a moderate scale for less than fifty millions of dollars, nor manned in time of war with less than fifty thousand men, and in peace, two thousand. And when done, they avail little; because all military men agree, that wherever a vessel may pass a fort without tacking under her guns, which is the case at all our sea-port towns, she may be annoyed more or less, according to the advantages of the position, but can never be prevented. Our own experience during the war proved this on different occasions. Our predecessors have, nevertheless, proposed to go into this system, and had commenced it. But, no law requiring us to proceed, we have suspended it. If we cannot hinder vessels from entering our harbors, we should turn our attention to the putting it out of their power to lie, or come to, before a town, to injure it. Two means of doing this may be adopted in aid of each other. 1. Heavy cannon on travelling carriages, which may be moved to any point on the bank or beach most convenient for dislodging the vessel. A sufficient number of these should be lent to each sea-port town, and their militia trained to them. The executive is authorized to do this; it has been done in a smaller degree, and will now be done more competently.