REVOLTING TURRETS. 



721 



tbare is no limit to the possible size and thick- 

 ness. The illustration on page 722 represents 

 a cordon of three of these turrets arranged for 

 the protection of a harbor. They are supposed 

 to be one hundred feet in diameter, with two 

 tiers of guns. They rest upon a structure of 

 iron-clad masonry, in which are contained the 

 magazines and steam, engine. The diagram on 

 page 720 presents a sectional view of a turret, 

 cut down vertically through the centre so as to 

 show the interior arrangements. Directly un- 

 ber the dome-shaped roof is a platform resting 

 upon a central shaft, which revolves independ- 

 ently of the turret, and not by means of the 

 steam engine. This is the station of the com- 

 mander during action. In the roof is a narrow 

 opening through which, by means of a fixed 

 telescope, he keeps watch of the enemy. At 

 his hand is a wheel, connected by rods and 

 gearing with the shaft so that he can turn the 

 platform in any direction, and thus keep his 

 telescope always pointed upon the object of 

 attack. If this moves, he follows it, precisely 

 as a sharpshooter with a telescopic rifle follows 

 the course of a moving object. By an arrange- 

 ment of signals he can also give any directions 

 for the management of the vessel or of the guns. 

 As the turret revolves .each gun is for an instant 

 brought in the course of every revolution di- 

 rectly in a line with the commander's telescope. 

 If the gun is discharged at that instant, the 

 ball must go straight to its mark. Provision is 

 made for doing this with unerring certainty. 

 Each gun in the act of passing under the ver- 

 tical line of the telescope, is discharged by 

 means of an electric current. This telescope 

 being held pointing to the object of attack, 

 every gun in the battery is really aimed by the 

 commander. This automatic sighting and dis- 

 charge are essential features of the invention ; 

 they obviate the uncertainty of aim, which is 

 the main objection against the towers hereto- 

 fore built. The commander aims and dis- 

 charges every gun in his battery ; the gunners 

 have only to load, run the piece to the port- 

 hole, and place the fuse in the vent. This can 

 be done in one minute. A turret of one hun- 

 dred feet in diameter will give ample space for 

 sixty guns in two tiers. If it revolves once a 

 minute, which is equal to about three and a 

 half miles an hour, its effective fire is sixty 

 guns in a minute directed with unerring aim 

 upon any point of the circle an offensive 

 power greater than that of any fortress in the 

 world. For defensive power, such a turret 

 can be made absolutely invulnerable. The 

 "monitor" turrets are Irom nine to thirteen 

 inches thick ; but in a land turret, if one foot 

 is not sufficient, there may be two or five. The 

 only limit is the crushing weight of the struc- 

 ture upon the steel rollers on which it revolves. 

 The main purpose of a land turret is for 

 harbor defence. The illustration on page 722 

 shows the adaptation of a cordon of turrets for 

 the protection of the harbor of New York. 

 The point of defence is supposed to be the 

 VOL. iv. 46 A 



Narrows, where the channel is about one- 

 fourth of a mile wide. A tower is built upon 

 each shore, and another is placed midway. An 

 enemy approaching would be exposed, from the 

 moment he came within range, to the concen- 

 tric fire of these three forts, each capable of 

 delivering sixty shot in a minute with an accu- 

 racy hitherto unknown in gunnery. To pasi 

 these forts he must come, with broadsid. 

 posed, within one-sixteenth of a mile of the 

 muzzles of one hundred and twenty gun?, 

 aimed with the precision of a telescopic rifle. 

 Should he succeed in passing, his stern would 

 be exposed, so long as he continued within 

 range, to the fire of all the towers. The guns 

 may be of the largest calibres, for it has been 

 demonstrated that the heaviest ordnance can 

 be discharged within a turret with less incon- 

 venience than from the casemate of a forhv". 

 It would seem that nothing that can float could 

 sustain this fusillade for a quarter of the time 

 in which the swiftest steamer would be exposed 

 to it. A single hostile steamer once within 

 range of New York, Boston, or San Francisco, 

 could impose its own terms. To this system 

 of turrets Mr. Timby therefore proposes to add 

 a series of chains. These stretch from turret 

 to turret, and are attached to windlasses turned 

 by the steam engine within. Buoys are fast- 

 ened to the chains, leaving their specific gravity 

 just sufficient to sink them. In time of peace 

 they lie quietly on the bottom, presenting no 

 obstruction to navigation. On the approach 

 of an enemy they are drawn np, not taut, but 

 so as to hang swaying in the water at such a 

 depth as to prevent the passage of a vesse ; 

 the greater part of their weight being supported 

 by the buoys, almost their entire tensile strengtli 

 is available as a barricade. These chains may 

 be of any required size and number. They 

 possess the character of an immense iron raft, 

 sufficiently submerged to be wholly out of the 

 reach of an enemy. The most powerful steam- 

 er striking them would merely sway them back, 

 while its own momentum would be destroyed, 

 and it would be helpless under the guns of the 

 turrets. Outside of these chains it is proposed 

 to stretch a line of torpedoes attached to a 

 chain from tower to tower across the channel. 

 These can be drawn directly under the vessel 

 while detained, and exploded at the precise in- 

 stant desired by the discharge of an electric 

 current. This obviates the great practical de- 

 fect in all systems in which torpedoes have 

 been employed, that the discharge is a matter 

 of chance. The diagram on page 722 shows 

 the details of the system of turrets, chains, 

 buoys, and torpedoes, whjch combines in itself 

 all the elements of defensive warfare hitherto 

 employed. Its cost for construction and main- 

 tenance must be less than that of stone for- 

 tresses. The defensive works of Charleston 

 cost more than would be required to render 

 New York impregnable to the combined navies 

 of the world. Masonry having been shown to 

 be useless against modern artillery, the sole 



