In order to prevent this difficulty from arising, all salt-water steamships and many that are used on fresh water, for lakes and rivers often contain sediment that would foul the boilers, use condensers. These are water-cooled systems of pipes through which the steam is led after its final release from the engines. The steam, which of course is still hot, is led through these carefully cooled pipes, and in coming into contact with the cool walls of the pipes is condensed, just as the moisture in your warm breath is condensed in the winter when you breathe against a cold window pane. This condensation turns the steam into water once more, and it is led back to the tanks where it is held in readiness to be sent again to the boilers. The auxiliary machinery of such a ship as the _Majestic_ or the _Leviathan_ is even more complicated than, although not so powerful as, the engines which drive the propellers. I have mentioned the ventilation system of the stokehold, but that is only a small part of the system that ventilates every nook and cranny in the whole huge structure. There are refrigerators, which are capable of keeping in cold storage large quantities of perishable products. There is even, on the _Majestic_, a second refrigerating plant intended to cool a cargo hold in order that perishable freight may be carried. Another important auxiliary machine on the _Majestic_ is a Diesel engine for generating electricity in case something might put the main generating plant out of commission. With this emergency plant, power is assured for lighting and for lowering the lifeboats. In order to handle so great a ship when the engines are necessarily at such a distance from the “bridge” where the officer in command has his post when the ship is under way, it is necessary to have some means of communication between the bridge and the engine room. A person driving an automobile is not only in command of the steering of the machine, but is also in direct charge of the engine, the gears, and the brakes. Not so the captain of a ship. Neither he, nor any of the men with him on the bridge, has any means of starting or stopping the engines. There is a man at the steering wheel, of course, but the men who start and stop and reverse the engines are far below the bridge and far aft, hidden away beyond where any shouted orders could possibly reach them. Yet the engines must be operated as the captain commands, for he is the man who can see what must be done—he is the one upon whose judgment the safety of the ship depends. In order to bridge the gap between the bridge and the engine room an apparatus called the “engine-room telegraph” has been perfected. There are a number of designs, but all of them by simple mechanical means permit the officer on the bridge to operate a handle and set a hand on a dial placed in the engine room so that it signifies the officer’s orders. [Illustration: THE _HOMERIC_ _A British liner belonging to the White Star Line._]