The necessity for wireless installations on all sea-going vessels has been brought home to us in startling fashion on several occasions during the last few years. Time after time we have read thrilling accounts of ocean disasters in which wireless has come to the rescue in the most wonderful way. A magnificent liner, with its precious human freight, steams majestically out of harbour, and ploughs its way out into the waste of waters. In mid-ocean comes disaster, swift and awful, and the lives of all on board are in deadly peril. Agonized eyes sweep the horizon, but no sail is in sight, and succour seems hopeless. But on the deck of that vessel is a small, unpretentious cabin, and at a desk in that cabin sits a young fellow with strange-looking instruments before him. At the first tidings of disaster he presses a key, and out across the waters speed electric waves bearing the wireless cry for help, “S.O.S.,” incessantly repeated. Far away, on another liner, is a similar small cabin, and its occupant is busy with messages of everyday matters. Suddenly, in the midst of his work, comes the call from the stricken vessel, and instantly all else is forgotten. No matter what the message in hand, it must wait, for lives are in danger. Quickly the call is answered, the position of the doomed ship received, and the captain is informed. A few orders are hurriedly given, the ship’s course is changed, and away she steams to the rescue, urged on by the full power of her engines. In an hour or two she arrives alongside, boats are lowered, and passengers and crew are snatched from death and placed in safety. This scene, with variations, has been enacted many times, and never yet has wireless failed to play its part. It is only too true that in some instances many lives have been lost, but in these cases it is necessary to remember that without wireless every soul on board might have gone down. The total number of lives already saved by wireless is estimated at about 5000, and of these some 3000 have been saved in the Atlantic. Ship aerials are carried from one mast to another, as high up as possible. The transmitting and receiving apparatus is much the same as in land stations, so that it need not be described. In addition, most liners carry a large induction coil and a suitable battery, so that distress signals can be transmitted even when the ordinary apparatus is rendered useless by the failure of the current supply. Most of the wireless systems are represented amongst ship installations, but the great majority of vessels have either Marconi or Telefunken apparatus.