which, at a speed of 8–9 knots, could drive the boat a distance of 1,000 miles. Should it be necessary to transport her to a greater distance, her water tanks could be filled with coal, enabling her to steam 2,500 miles. Two vertical propellers, one forward and one aft, kept the vessel submerged and overcame the retained force of buoyancy (500 lbs.). The boat was lighted by candles; without any special provision of air it contained enough for a crew of nine men for about six hours. _Nordenfelt IV._ made her passage from Barrow-in-Furness to Southampton through some heavy seas, and during the voyage she was tested by her commander in every wind and every condition of wave and sea, and she proved that she was capable of being manœuvred in any weather, however bad. On the 26th of May, 1887, she underwent her first examination before a body of critics, composed for the most part of skilled, experienced scientific officers of both branches of the Service. She was first run with nothing above water save the two conning towers and a few inches of her back, at the rate of about six miles an hour. The time occupied by the trial in the awash condition was 1½ hours, and at the end of the time a sufficiency of steam was stored up in the boilers to drive her a distance of about 24 miles. On the pumps being put in motion, some 20 tons of water were pumped out in eight minutes. The funnels were then fixed, the fires relighted, and the _Nordenfelt_ was soon making 15 knots on the surface. On December 19, 1887, a semi-official trial of the _Nordenfelt_ took place, when she manœuvred successfully both on the surface and submerged, but no attempt was made to fire the torpedoes. “The neutral tint she was painted,” wrote the special correspondent of the _Engineer_, “rendered her almost invisible at the distance of even a few hundred yards, while as a target she presented nothing to attack save the two conning towers and a few inches of her turtle back, and as these were of great strength and rendered still more invulnerable by their shape, it is all but certain that no gun carried on any other torpedo boat would ever do her the slightest injury, while she at the same time possesses the enormous advantage of being able to attack without smoke, or fire, or noise. Indeed, given these advantages of a minimum of target and a total absence of noise and smoke, we fail to see what more could be desired in any vessel of war.” In a leading article in the issue of December 23, 1887, the _Engineer_ said: “We may—we hope we shall—have quite a little fleet of _Nordenfelts_ when Christmas comes round again. When once Columbus had shown the way to America, the water was freely traversed.”