A broken shaft is still a disagreeable possibility, but if one of the two shafts in a twin-screw ship breaks, the other, as with the engines, remains to avert complete disablement. An ingenious device has lately been patented to prevent a repetition of one of the most serious of recent disasters, which was caused by the wearing away of the bracket upon which rests the final bearing of the shaft. As this bracket is, in the largest ships, fully sixty feet from the stuffing-box, a new danger is created from the fact that it is far outside the hull and out of sight of the engineers. The invention referred to consists simply of a couple of completely insulated wires, positive and negative, connected by a battery, an indicator, and an alarm-bell in the engine-room. The wires run under the shaft out through the stuffing-box, and through the casing which protects the shaft from the sea; then they enter the bracket, where they turn from the horizontal to the perpendicular, and terminate about three-quarters of an inch from the surface of the bearing. Should the surface wear away so as to imperil the shaft, the latter would instantly come in contact with the ends of the wires, the insulation would be broken, the current closed, and the alarm-bell rung. Then, of course, the engine would be stopped until an examination could be made. Though it promotes safety and is winning favor, the twin screw has been applied so far only to the City of Paris, the City of New York, the Teutonic, the Majestic, the Columbia, the Normannia, the Fürst Bismarck, and the Augusta-Victoria. Credit for the infrequency of broken shafts does not belong wholly to this device, therefore, but in a much larger measure to the substitution of steel for iron and other improvements in the form and materials of the marine engine. [Illustration: The Lightship, off Sandy Hook.] The City of New York and the City of Paris are also provided with double bottoms, so that, should the outer skin be torn, the inner one would still exclude the sea; and the efficacy of oil in calming the troubled waters has been so well established that apparatus for its distribution is placed in the bows. The number of officers and seamen has been augmented, so that the staff of navigating officers now comprises the captain, the chief officer, two second officers, two third officers, and two fourth officers. Great improvements have also been made in the mariner’s compass and in the patent log and sounding machine. The latter can be used when the ship is going at a high rate of speed, and it records not only the depth of water but the character of the bottom, which is nearly always a clue to the position of the ship when other signs fail. Had these instruments been less perfect, we could not have made our way, with so little delay, past Fastnet and up the Channel to Holyhead, when the fog descended as we were making land.