GEN. TODLEBEN is superintending the works for strengthening Cronstadt, and barring the approach to the Neva. In one channel leading to the back of Cronstadt, about 300 lighters laden with stones have been sunk, so that now in no part is there more than 4 feet of water. In another channel 300 infernal machines are to be laid, each of which will contain 7 pounds of powder, and explode by a slight touch of a vessel passing over. On the main island of Cronstadt several large earthworks are being thrown up. Some of these earthworks are to be covered with 7½ inch plates, placed on an angle of 45°, and curved over the top so as to form a cover. Another means of defense consists of a submarine boat of colossal dimensions, in the construction of which about 200 tuns of iron and steel are to be used. It is to have engines worked by compressed air, to have a very strong beak, with provision for attaching large cylinders charged with powder to the bottoms of vessels to be fired by electricity.
The parties navigating the vessel will see what they are doing by means of bull's eyes, and they will regulate the depth at which they swim, keeping quite close to the surface. By the 1st of June, 1864, the Marine Department confidently expects to have at Cronstadt 16 iron-clad vessels, and they consider these a very poor fleet for such a Power as Russia. Enormous exertions are being used to obtain the requisite quantity of guns, with suitable ammunition, for all the forts, earthworks, and ships, and it will perhaps be found that the Russians have really got ahead of England in guns, and shot-guns are now being produced in about a dozen factories, working day and night. and in a few days another Elswick will commence. Its production will be solid cast-steel guns, from the 6-pounder to the 11-inch gun, which latter is to fire a 500-pound shell.
To provide the necessary shot and shell to their guns, all the founderies around St. Petersburg have orders varying from 15,000 to 50,000 each. All the shot and shell from 12-pounders upward are for field-guns. Round hammered-steel shot are also being prepared to suit the naval 60-pound gun. One firm alone has on hand 30,000 of these. Land-artillery forces are also adopting the steel guns for their service. In anticipation of war and the supplies of armor-plates being stopped, two forges are erecting, capable of making 10,000 or 12,000 tuns of armor-plates per year. Large supplies of saltpeter have been purchased during the summer, and the powder-works have been extended, and are working night and day. Flour has been very largely bought for delivery in February, and for those places to which the ordinary route is by water in spring extra prices are being paid for winter delivery. Two years' supply of coal has been provided for the fleet.