Moreover, in some of the latest battleships of the dreadnought type the practice has been followed of permitting no doors of any description to be cut through the bulkheads below the water-line. Access from one compartment to another can be had only by way of the decks above. Furthermore, all the openings through the protective deck are provided with strong watertight hatches or, as in the case of the openings for the smoke stacks, ammunition-hoists, and ventilators, they are enclosed by watertight steel casings, extending to the upper decks, far above the water-line. In the later warships, further protection is afforded by constructing the first deck above the protective deck of heavy steel plating and making it thoroughly watertight, every opening in this deck, such as those for stairways, being provided with watertight steel hatches. This deck, also, is thoroughly subdivided by bulkheads and provided with watertight doors. It sounds like a truism to say that a watertight bulkhead must be watertight; yet it is a fact that only in the navy are the proper precautions taken to test the bulkheads and make sure that they will not leak when they are subjected to heavy water pressure. Before a ship is accepted by the government, every compartment is tested by filling it with water and placing it under the maximum pressure to which it would be subjected if the ship were deeply submerged. If any leaks are observed in the bulkheads, decks, etc., they are carefully caulked up, and the test is repeated until the bulkhead is absolutely tight. Now, here is a practice which should be made compulsory in the construction of all passenger-carrying steamships. Only by filling a compartment with water is it possible to determine whether that compartment is watertight. To send an important ship to sea without testing her bulkheads is an invitation to disaster. The amount of water that may find its way through a newly-constructed bulkhead is something astonishing; for although the leakage along any particular joint or seam of the plating may be relatively small, the aggregate amount will be surprisingly large. [Illustration: Between the boiler rooms and the sea are four, separate, watertight walls of steel. The whole is covered in by a 3-inch watertight steel deck. MIDSHIP SECTION OF A BATTLESHIP] Let us now pass on to consider the actual efficiency of the watertight subdivision as thus so carefully worked out in the modern warship. Thanks to the Russo-Japanese war, which afforded a supreme test of the underwater protection of ships, the value of the present methods of construction has been proved to an absolute demonstration.