It had been snowing hard for the past twenty-four hours, but as the light of a new day strengthened it eased somewhat, and away to the westward the blue outline of the land became visible. The fitful wind of the night rose to a stiff breeze, but no one paid much attention to the increasing volume of bitter spray which swept the deck as the grey-green rollers put on their white caps of foam, for the ship was heading towards the harbour and their vigil was over until darkness again closed down. Few things are more trying to the temper than to be kept waiting for relief after a bad spell at sea, and but few crimes are more heinous than to leave the watched area before another patrol takes up the never-ceasing duties. Therefore, if peace and quietness and an absence of insulting signals counted for anything, it ill behove any ship in the day patrol to keep her opposite member of the night guard waiting. This time the relief was late and the M.L. steamed angrily up and down, with all eyes strained shorewards. Then the first of the line of armed trawlers and motor launches crawled out of the harbour in a smother of black smoke. When barely half-a-mile of sea separated the incoming and outgoing ships a loud reverberating boom rolled over the sea. So great was the explosion that the shock of it was felt rather than heard, and a gigantic column of black smoke, rising over 100 feet into the air, appeared to engulf the leading unit of the trawler patrol. Regardless of the danger, the C.O. of the motor launch sent his swift shallow-draught boat flying over the mine-field into the floating debris. The only two mangled survivors had, however, been picked up by the trawler astern of the ill-fated vessel, which had been literally blown to pieces, nothing remaining afloat when the smoke cleared away except a signal locker and a few timbers. [Illustration: A MOTOR LAUNCH OF THE NAVAL PATROL _Yachting Monthly_ _Photo by Com. Sir A. Lee Guinness_] More than one of the other vessels, whose engines had been stopped immediately the explosion occurred, narrowly escaped drifting down with the tide on to the field of hidden mines, but with the skill and presence of mind gained by similar experiences in the past both the trawler unit and the M.L. flotilla were extricated without further loss. It was evident from the fact that several of the mines were barely submerged and could be dimly seen from the decks that the work of laying them had been done hastily under the cover of night, and a sense of keen sorrow and disappointment pervaded the vessels of the night guard. Once again climatic conditions had favoured the enemy. In those long winter hours of impenetrable blackness and driving snow no watch, however efficient, could be relied upon to prevent such operations from being occasionally carried out. It was merely the chance of war, but nevertheless it was felt keenly, and the sense of responsibility was not dispelled until some weeks later.