“_Armament._—The main battery, which consists of twelve 6-inch breech-loading rifles, all on centre-pivot mounts, with two-inch segmental steel shields, is arranged on sponsons so as to obtain the greatest possible arc of fire. The forecastle, the poop, and the bridges have been as much as possible availed of to shelter the guns. The two guns forward and the two guns aft converge their fire a short distance from the ends of the ship, and the broadside can be concentrated within 100 feet of the side. Four above-water torpedo-tubes are provided on the berth-deck, and two direct ahead under-water torpedoes in the bow. The secondary battery is composed of four 47-millimetre revolvers, four 57-millimetre single-shots, two 37-millimetre revolvers, and one short Gatling. The coal capacity is 850 tons. The complement of men 300.... “To appreciate what is required to make nineteen knots an hour at sea, we have only to remember that the _Umbria_ and _Etruria_ are 500 feet long, with more than 12,000 tons displacement and 14,500 indicated horse-power, ordinarily making 18½ and on special occasions 19 knots an hour. Now, to increase her speed to 20 knots an hour, the _Umbria_ would require about 19,500 horse-power, which means 5000 extra horse-power for the extra knot. For a second extra knot would be required about 6000 horse-power more, making about 25,000 horse-power necessary to develop a speed of 21 knots.” Gun-boats Nos. 3 and 4 are to be copies of gun-boat No. 1. No designs for the floating batteries and the torpedo-boat have been published. The _Stiletto_ is one of the famous Herreshoff boats, and is now being tested in consequence of a favorable report made by a board of officers. On July 23, 1886, with a total displacement of twenty-eight tons, she made an average of 22.12 knots as the mean of four runs over the measured mile in a rough sea and fresh wind, and on July 30th she attained an average of 22.89 knots. These were excellent results for a boat ninety feet in length, and promised that the type, with certain modifications, was equal to greater demands. The trial data of this year have not yet been published, though it is unofficially reported that her performance was equally as creditable. UNITED STATES NAVAL ARTILLERY.