without increase of draft. Being submerged, all that part of the hull not covered by the shield is protected by the water from the projectiles of an enemy. The shield proposed for such improved form of vessel is of wood, covered on the exterior with iron, the surface inclined at such an angle as will permit the guns to be worked in the usual manner and yet deflect projectiles impinging upon it. This angle will be between 40° and 50°. The eaves of the shield may be about two feet under water. To divide and prevent the water over the submerged part of the vessel from banking up at the forward or after ends of the shield in going ahead or astern, thereby retarding her progress and perhaps preventing the use of the bow or stern gun, a false bow and stern or tanks are constructed upon the submerged portion of the vessel corresponding more or less in form with the hull below. The false bow and stern may be decked, in which case they should not be so high above water as to interfere with firing of the bow and stern guns. These tanks may be used as reservoirs of water by which the draft of the vessel may be regulated at will. The stem, being submerged, may be fitted as a ram to strike the wooden bottoms of iron-clad vessels. This plan of construction is applicable in plating effectually ships built in the usual manner; it being simply necessary to remove the upper works and to cut them down forward and abaft the shield sufficiently to submerge the ends when down to the load-line, as illustrated in the case of the Confederate States steamer Virginia, which vessel was constructed in accordance with the plan herein set forth, furnished by me on the 23rd day of June, 1861, to the Honorable S. R. Mallory, Secretary of the Navy, to William P. Williamson, Chief-Engineer Confederate States Navy, and John L. Porter, Constructor Confederate States Navy, the two latter having been directed by the Honorable Secretary of the Navy, in conjunction with myself, to devise an iron-clad vessel. And this plan was applied to the Merrimac in preference to constructing a new vessel of eight or ten feet draft, in consequence of the impossibility of procuring in time boilers and engines suitable to the purpose. The boilers of the Merrimac were good, and as the chief-engineer was of opinion that the engines could be speedily repaired, it was considered expedient to apply the plan to her.
"What I claim as my invention, and desire to secure by letters patent, consists in so constructing the hull of a vessel that her bow