these canals converging on the waterways of Bruges in such a manner that vessels of a certain limited size could pass from Ostende to Zeebrugge, and vice versa, without actually proceeding into the open sea. A series of small canals also connected Bruges to Antwerp, via Ghent, but this canal system, being only constructed to accommodate barges, did not materially add to the value of Bruges as a harbour for sea-going vessels.

Of the three canal systems connecting at Bruges, the canal to Zeebrugge easily held first place in importance. This canal was built by the Belgians. It was commenced in 1896 and completed in 1907. Six and a quarter miles in length, it was almost entirely straight throughout. It could accommodate torpedo-boat destroyers or submarines, both of the largest size, and could, if required, have been used by light cruisers.

The Harbours in Flanders

At the seaward end of the Ostende and Zeebrugge canals, locks were constructed so that vessels could pass from the canals to the sea, or the reverse, at any state of the tide, without lowering the level of the water in the canal.

The above-mentioned harbours were used for naval purposes by Germany as follows. Bruges was chosen as the main naval base. Shelters for protecting submarines from aerial attack, floating docks, repair workshops, all the other facilities which go to make a modern dockyard for small vessels, and the necessary stores and ammunition, were to be found there. The number of naval craft based on Flanders appeared to vary considerably; but, at the beginning of 1918, approximately eighteen submarines and twenty-five destroyers or torpedo-boats would be at Bruges on an average day. The submarines lay in the special shelters which were covered by roofs of reënforced concrete several feet in thickness. Bruges, then, was not only the dockyard but also the resting-place of practically all the German naval craft based on Flanders.

The sea exits from Bruges, as already mentioned, were situated at Ostende and Zeebrugge. There was some doubt, however, whether the Bruges-Ostende canal could be used for the passage of anything larger than very shallow draught vessels such as motor boats or barges. The Ostende canal was known to be narrow, tortuous, and shallow; it had been constructed many years earlier than the Zeebrugge canal.

At Zeebrugge and Ostende a few German craft were usually stationed for duties of an immediate nature such as mine-sweeping, patrolling, and duties connected with the defence of the coast. These harbours were specially useful as taking-off places for vessels which had concentrated in readiness for operations at sea, or as bolt-holes for the same craft when pursued by our patrol vessels. Both harbours were open to bombardment from the sea; that reason, more than any other, probably influenced the Germans to use Bruges for their main base. Ostende, being more open to attack from the sea and air than was Zeebrugge, was the less important harbour of the two.

Blankenberghe harbour, owing to its small size and shallow depth, was used as a base for the German armed motor boats; it is believed that about thirty were stationed there. This harbour, being unconnected with the canal system, was not in direct inland communication with Bruges by water.

In addition to the submarines and torpedo craft already mentioned, the Germans had a large number of trawlers based on the various harbours for mine-sweeping and patrol duties. At Zeebrugge they had their largest seaplane base in Flanders; another seaplane base was situated at Ostende.

In due course Flanders had become a veritable hornet's nest. Let us consider for a few moments to what extent these hornets could trouble us.

Our Lines of Communication

Across the English Channel, and especially in its eastern portion, we had established lines of communication of tremendous importance. It is no exaggeration to state that, every few minutes of the day and night, a vessel, of one sort or another, left the English shore for France with her cargo of personnel, guns, ammunition, food or fuel, etc. Day after day, night after night, for months on end, a constant stream of vessels poured across the Channel in support of the Allied armies or on the return trip to English ports with wounded, men to whom a welcome spell of leave had been granted, empties for refilling, motor transport vehicles for repair, and the like. The wounded were carried in hospital ships; but, as the world knows and can never forget, the Germans ruthlessly torpedoed them whenever the chance offered, regardless of the Geneva Convention, heedless of the damnable inhumanity of the proceeding, seeking only for opportunities for indulging in the frightfulness which formed part of their Kultur.

All these vessels were continually open to attack, not only from submarines but also from the surface craft and aircraft based in Flanders. At any chosen moment, preferably at night or during misty days, these hornets could emanate from Ostende or Zeebrugge on their deadly missions. Further westward our trans-Atlantic lines of communication offered innumerable opportunities for the German submarine commanders to display their brutality against comparatively defenceless merchant vessels, or to attack transports carrying munitions of war and troops from the American Continent. The passage through the English Channel afforded the most direct route for German submarines proceeding to, or returning from, their hunting-grounds.

The mercantile traffic off the southeast coast of England and in the entrance to the Thames was also within easy reach of the German bases in Flanders; so were our seaside resorts, such as Ramsgate and Margate, which provided favourable opportunities for bombardments with resultant casualty lists of innocent women and children.

Dunkerque and Calais on the French coast were the nearest seaport objectives to the Flanders coast; they both experienced frequent aerial attacks and an occasional bombardment from the sea.

As a counter to the German craft in Flanders the British Admiralty had established a force known as the "Dover Patrol." As the name implies, this force was primarily based on Dover. Their duties were mainly those of protecting the transports bound across the English Channel, preventing the German naval craft from passing through the Straits of Dover, and watching the exits from Bruges so as to obtain timely information of concentrated German forces putting to sea. The story of the Dover Patrol is of intense interest, but so many pages would be required to do it even bare justice that I can only refer the reader to books written especially on that subject. Suffice it to say here that, day and night, winter and summer, fair weather and foul, the Dover force patrolled the sea so successfully that the German attempts to use their surface craft for attacking the Allies were few and far between. The difficulties of preventing the submarines passing through the Straits of Dover were immense. We must realise that the maximum portion of a submerged submarine visible above water amounts to a periscope of a few inches in diameter. Compare that dimension to the width of the Strait which at its narrowest part is twenty miles. A few inches in twenty miles—if I have calculated aright that means that the visible portion of the submarine would cover little more than one-millionth part of the surface between Dover and Cape Grisnez. And when we also realise that the periscope would only be raised above water for a few seconds at long intervals we shall begin to understand the difficulty of the problem. Yet, as we know now, the Dover Patrol force, under the direction of Vice-Admiral Sir Roger Keyes, eventually rendered the passage through the Straits to