Before we can appreciate this aspect of the work of the Navy in the war, we must gain some idea of what is implied by the military service of these armies in the field. It is not enough to dispatch armies. They must be maintained and supplied. The communications of an army are vital to its operations, and the communications of all the armies that England is employing are by sea, and are guarded by the Navy. It would not be an easy thing to estimate the vast requirements of fighting forces; but that is unnecessary. They are on an infinitely greater scale, in proportion to the strength of the troops employed, than in any previous war. Guns are far more numerous and much heavier than they were. The expenditure of ammunition has gone beyond all anticipation, and a real fleet is required for its transport. Horses, mules, many descriptions of heavy and light ordnance and ammunition for them, warlike and general stores of innumerable kinds, aeroplanes, balloons, the gigantic “tanks,” hospitals and hospital requisites, clothing, food, forage, camp equipment, transport vehicles, traction engines, pontooning, railway, telegraph, building, and mining material, locomotives of many kinds, petrol, and a hundred other stores and things are necessary, and they must day and night be in transit, without rest or pause. It will illustrate the gigantic nature of the operation if we record that between November, 1916, and June, 1917, 2,000 miles of complete railway track were shipped, with nearly 1,000 locomotives, and other supplies by railway companies. Labour and work for a hundred different services have to be provided also. The United States and other countries have contributed enormous supplies, and, with the coming of the American Army, the volume of the ceaseless torrent—the veritable Niagara—will increase still more. History has no parallel for such operations. This vast business being the charge of the British Navy and of the navies allied with it, we see how great an object it must be of the enemy to strike at the lines of supply. That they have completely failed would appear almost miraculous, if we did not know that the reasons for the failure are altogether of a practical character. It was inevitable that there should be some losses when submarines and mine-layers were at work, but the destruction effected has been a mere fraction of the whole, and the influence upon the campaigns is entirely negligible. The Ministry of Munitions imports 1,500,000 tons of material every month. The most considerable loss due to attack has been in the matter of shell components, but it did not amount to more than 5.9 per cent. of the whole supply from the beginning of the submarine campaign up to June, 1917. The most serious disasters were in the Mediterranean, where submarines sank the French transports _Provence II._ and _Gallia_, engaged in the Salonika expedition, with the loss of about 1,600 lives. The enemy will certainly continue his efforts.