These boats preserve the "porpoise" shape, are equipped with wireless apparatus, and provided with panoramic periscopes to enable them to sight their target when submerged. There is no necessity nowadays to describe the principle of a periscope, since little portable patterns of this optical instrument, of various types, made for use in the trenches, can be seen exposed for sale almost anywhere. But, of course, those in use on a submarine are of a large and highly perfected type. The conning-tower of the "E" boats is armoured, and they carry a couple of quick-firing guns of 3 inches calibre in recesses on their decks, closed in by folding doors. These little weapons can be quickly raised into position by an arrangement of hydraulic machinery, and by merely pressing a lever they sink down and are boxed in again in a second or two.[71] They are so mounted as to be able to fire at a very high elevation, in order to defend the boat against bomb-dropping air-ships or aeroplanes, but, of course, can be used against surface vessels in the same way as those of the German submarines, which have made several attempts to sink merchantmen. As a modern Whitehead has a range of something like 3 miles, travels at a speed of 50 miles an hour, and carries a heavy charge of high explosive in its head, we need not dwell on its formidable nature, which has been amply proved in the course of the war. It has also been equally proved that it is almost impossible for a submarine to torpedo a fast and well-handled vessel once it has located the position of its attacker. [Illustration: _Photo. Cribb, Southsea_ THE BRITISH SUBMARINE _E 2_ It was a boat of this class, _E9_, by which the German cruiser _Hela_ and a destroyer were sunk by Lieutenant Max Horton; and another, _E11_, specially distinguished herself at the Dardanelles.] "The modern submarine has every comfort commensurate with the size and service of the vessel. The principal item making for comfort is, of course, properly-prepared food.... As time passed, electric cooking-apparatus was installed. This was always subject to the many troubles inherent in early electrical heating-apparatus. However, the idea was a step in advance. To-day there is installed a well-arranged oven, four or five independent plates for cooking meats and vegetables, and an urn for keeping coffee constantly hot and on tap when cruising. All of these things, though small in themselves, make for contentment in the crew."[72] Whether or not such cooking appliances are installed in our own submarines I am unable to say, but there is no doubt that everything necessary for the comfort of their crews has been provided by the Admiralty, and the boats themselves are very like the American submarines which are referred to above.