Of the serious risk to a ship of collision with an iceberg, it is superfluous to say anything here. The swift sinking of the world's greatest steamship has driven that lesson home, surely, for all time to come. But there are two other forms of accident on the high seas--collision with another ship and the running down of a derelict--whose possibilities of disaster are scarcely less. For if the huge steamships of our day, moving at high speed, are such potential engines of destruction, it follows that the damaging effects of collisions are proportionately increased. If a 60,000-ton ship, such as the _Titanic_, while running at high speed, were struck on the beam by a vessel of large size, it is quite conceivable that the outside plating of three of her compartments (not merely the "two adjoining" of standard shipbuilding practice) might be broken in, or the seams and butts started, before the energy of the colliding ship was absorbed and the two vessels swung clear of each other. The average length of the compartments of the _Titanic_ was about 53 feet. At 21 knots she would move forward about 35 feet in one second. Hence, in a few seconds' time (even allowing for her slowing down due to the drag of the other ship), her enormous energy of over 1,000,000 foot-tons would cause her to grind along past the broken bow, surely more than the 100 feet or so which would suffice to involve three compartments. If three compartments amidships were opened to the sea, it would mean the admission of some 12,000 to 15,000 tons of water. Even more insidious is the menace of the abandoned and water-logged ship--the justly dreaded derelict--which, floating low in the water, and without a light to reveal its position, may lie directly in the path of the high-speed ocean liner. So slightly does the derelict project above the surface, that it is almost impossible of detection by night from the lofty position of the lookout on a modern steamship. [Illustration: Test of fire mains is made every time the ship is in port. FIRE-DRILL ON A GERMAN LINER]