lock-gates at Zeebrugge, with her crew fallen in on the fore superstructure, her captain called for three cheers,--'As that's the last you'll see of Flanders.' The cheers were given very heartily--an involuntary tribute to the four years' work of the naval services at Dunkirk. All these things were yet to come when the third of the naval aeroplane raids into enemy territory was made on the 21st of November 1914. This, the successful attack on the Zeppelin sheds at Friedrichshafen, Lake Constance, was planned and executed to perfection. Lieutenant Pemberton Billing, of the Royal Naval Volunteer Reserve, left England on the 21st of October under Admiralty instructions. He arrived at Belfort on the 24th and, by the courtesy of the French general in command, obtained permission to use the aerodrome within the fortifications and its large dirigible shed as the starting-point for a raid. German spies were believed to be at work in Belfort, so arrangements were made for the machines to be brought into the place by road transport at night, and for their pilots to be boarded and lodged, during the whole of their stay, in the dirigible shed. Having completed these preliminaries, Lieutenant Billing carried out discreet inquiries which enabled him to draw up a chart of the proposed route, a complete plan of the Zeppelin factory, and a draft of instructions for the proposed raid. Meantime the French had themselves been meditating a raid on Friedrichshafen, and the Governor of Belfort had received some valuable reports on the factory and the prevailing weather conditions. After some discussion it was decided that as Zeppelins were intended to assist in the destruction of the British fleet, the Royal Naval Air Service should be privileged to pay the first visit, but that this privilege should lapse if the visit were not paid within thirty days. In the season of late autumn, when the barometer is high and the air calm, the whole of the Swiss plateau and the Rhine valley bordering it is often plunged in a thick mist which reaches to a height of about 3,000 feet. Above this sea of mist the air is clear and the flight of an aeroplane safe and easy. The course chosen from Belfort to Lake Constance, a distance of about 125 miles, was bent, like an elbow at an obtuse angle, round the northern border of Switzerland, so that Swiss neutrality should not be violated. It lay over country much of which is wooded and sparsely inhabited--first from Belfort to Muelhausen, thence over the Black Forest and some groups of wooded peaks to a point north of Schaffhausen. Here the prescribed course was to bend southwards, between the two arms of Lake Constance which stretch to the north-west, and when once the lake was reached the objective would be full in view.