64 ANNUAL OF SCIENTIFIC DISCOVERY 



der-magazine, communicating from the deck, just underneath the 

 tower, by hatches. In the after-end of the forward turret is the pilot- 

 house, which is two feet higher than the main structure. 



The turret gun decks, twenty inches below the main deck, consist 

 of a circular iron frame six inches deep by three-quarters of an inch 

 thick, supported by twelve wrought-iron ^earns two and a half inches 

 in diameter. This frame is further crossed at regular intervals by 

 fourteen wrought-iron beams, also six inches deep and three quarters 

 of an inch thick. At right angles with the latter a strong box girder, 

 twelve inches by eighteen inches across the angles, is riveted to the 

 circular frame, being strengthened in the middle by a heavy wrought- 

 iron column five inches thick. Upon the top of the fourteen beams, 

 previously mentioned, a wooden deck five inches thick is laid, to 

 which the gunways are made fast. In the centre of the turret the 

 gun is pivoted ; three ports are made for it in the turret two broad- 

 side, and one aft or forward, as the case may be. A lateral range of 

 eight degrees and a vertical one of ten degrees can be obtained for 

 the missile. From the lower deck, inside the turrets, two doors per- 

 mit communication with the forecastle, and also the engine-room and 

 officers' quarters. There are two water-tight compartments in the 

 vessel, one fore-and-aft, to which access is had by the usual man- 

 holes ; these can be filled with water, if desirable, in a short time, and 

 will, it is calculated, settle the ship one foot. The forecastle is large 

 and roomy, so much so that one hundred men can swing their ham- 

 mocks in it. Alongside of the vessel, just behind the casemates, are 

 the coal-bunkers, and immediately enclosed by them and two fore-and- 

 aft bulkheads are the steam boilers. Before a shot can strike the latter 

 it must pass through the inclined side, the coal, and also the two stiff 

 bulkheads or partitions just mentioned ; they are, therefore, very fully 

 protected. 



The Keokuk is propelled by engines of five hundred horse power, 

 which drive a true screw under each quarter of the vessel of about 

 seven feet diameter. 



Contracts have also been entered into between the United States 

 Government and Captain Ericsson for the construction of two iron- 

 plated vessels of a more formidable character than any hitherto es- 

 sayed by him. They will bear a general resemblance to the Monitor, 

 with such modifications as have been suggested by experience. One 

 of them is to be three hundred and twenty feet in length, and the 

 other three hundred and forty-one, with fifty feet beam. The vertical 

 sides are six feet in depth, and are to be protected with iron armor- 

 plating ten and a half inches in thickness, backed with four feet of 

 solid oak. 



The turrets are to be absolutely invulnerable. The contract pro- 

 vides that they shall be two feet in thickness, but the contractor has 

 leave to reduce the thickness, provided he can satisfy the navy depart- 

 ment that less will be sufficient. The engines are to be of sufficient 

 size and power to give an average guaranteed speed of sixteen knots 

 per hour. The armament will consist of fifteen-inch guns. 



But it is as rams that these two new vessels are expected to be 

 most efficient. Where the plates of the sides meet at the bow they 



