“The power required to impel a vessel through the water is augmented by her submergence. If 5,000 1–h.p. are required to drive a displacement of 120 tons at 28 knots, then rather more power will be required to drive 120 tons wholly submerged at the same speed.” This statement appeared in the _Engineer_ in the early part of 1901, but it appears that an exactly opposite opinion is held by many eminent authorities. For instance, at the discussion which followed the reading of Mr. Nordenfelt’s paper on Submarine Boats at the Royal United Service Institution in 1886, Mr. Anderson, C.E., stated that it was well known through the late Mr. Froude’s investigation that a fish-shaped vessel under water was in much more favourable circumstances for obtaining high speed than any vessel on the surface of the water, because it had been established theoretically that a vessel of easy lines completely submarine met with no resistance at all except the skin friction of the water, no resistance, that was to say, such as that which arose from the bow wave. Mr. Anderson went on to say that he believed that if Mr. Nordenfelt would apply a little more ingenuity and perseverance to the perfecting of his boat, the result would be the attainment of a very high speed under water, and consequently a most formidable vessel. Mr. Nordenfelt himself said that it was absolutely proved that the speed below for a given consumption of fuel for a given boat must be greater than the speed above, and Mr. J. J. Thornycroft recently explained to an interviewer that the resistance is less for a completely submerged body than one travelling on the surface, because no waves are created. “The water that is displaced in front,” he said, “simply closes in behind and helps to push the body forward. A boat moving on the surface throws out waves in front and on either side, and that means an absolute loss of energy. You will find that for this reason a ‘Whitehead’ torpedo travels faster under the water than on the surface.”[5] Footnote 5: _Daily Graphic_, November 10, 1900. ARMAMENT. The armament of the boats designed by Bushnell and Fulton was a case of explosive; the armament of the _David_ that sank the _Housatonic_ was a spar-torpedo, but the armament of all modern submarines is the automobile fish torpedo. Mr. Holland in his earlier designs provided his boats with guns, but submarine cannon firing heavy shells have since been discarded. In the new British submarines one torpedo expulsion tube is fitted at the extreme forward end of the vessel, opening outward 2 feet below the light water-line. Five Whitehead torpedoes, each 11 feet 8 inches long, are carried. SAFETY AND HABITABILITY.