206 Mr. Harvey on Square and 



injuring very materially the strength of the ship. It is proper how- 

 ever to add, that by removing the rudder-head, the gun could be run 

 out twenty-one inches farther than when it was in its former posi- 

 tion, which must be regarded as an advantage, since it diminishes, 

 in some degree, the danger of fire. 



The next position assumed for the gun, was that of D d, Fig 1, 

 plate III, forming with the principal axis X Y, the angle d D Y of 

 27° ; this direction affording the greatest possible bearing at the 

 stern, towards the opposite quarter of the ship, when the recoil was 

 limited to four feet*. The magnitude of the arc cd, between the 

 extreme bearings at the stern-port, was therefore found to be 30J^r°, 

 when the rudder-head was preserved ; but nearly a degree more 

 when it was removed. In this situation, however, the muzzle of the 

 gun was still farther tdthin the stern, than determined in the pre- 

 ceding experiment. 



From the foregoing experiments, it therefore appears that the 

 entire arc a b d b a surrounding the square stern, and which 

 amounts in quantity to 204°, may be separated into the 



Cab == 46° 

 <cc =47° 



three defended arcs 



'-a 6 = 46° 

 amounting together to 139° ; and into the 



two undefended arcs ^ " - 

 1.6 c = 32^° 



amounting jointly to 65° ; the sum of the defended and undefended 



arcs being 204°, as before mentioned. Of the defended arcs, it 



may be observed, that the first and last a b, ab, admit of a ready 



tionably certain, according to the de^ee in which the divergence of the lines 

 of fire is increased j and which in every practical case will be much more con- 

 siderable than what was stated above. It may also be remarked, that in order 

 to obtain the extreme lines of fire for the stern-guns, the muzzles were brought 

 so very far uithm the framework of the stern, as to render it, in the opinion 

 of the naval gentlemen present, extremely dangerous to fight the gun under 

 such circumstances. 



* In such an application of a gun, the breeching must be so ordered, as to 

 prevent a greater recoil. 



