Gentlemen:—With the introduction of the 8 inch converted rifle, the United States Navy has taken its first decided step in the practical development of a system of rifled ordnance; and it becomes a matter not only of interest but of the greatest importance to all naval officers, that they should be able to form a rational opinion of the value and probable results of this first experiment. We are all aware that in the composition of this ship's battery there is but little that is original with Americans; and in considering its details, those who have but lightly followed up the progress of rifle development in Europe find themselves lost in a maze of inquiries. Why, for example, is the Palliser mode of conversion taken instead of the Parsons? Why do we insert a tube into a gun of a large calibre instead of rifling and hooping an 8 inch smooth-bore on the old French plan? Why do we convert guns at all? If we build them, should they be of steel like the German, steel and wrought iron like the English, steel and cast iron like the French, or cast and wrought iron like our own Parrott guns? Should we have breech or muzzle loaders; mechanical fitting, expanding or compressing projectiles; regular or increasing twist, square headed or pointed solid shot &c.?