Our advance in the use of wireless telegraphy was very considerable indeed, and I owed a great debt of gratitude to Lieutenant-Commander Nicholson, the other wireless officers of the Fleet-Flagship, and the wireless officers and personnel of the whole Fleet. The progress was the more remarkable since, owing to extreme shortage of wireless personnel for the expanding Fleet and the large number of auxiliary vessels commissioned, we were forced to discharge many of the best operators in the Fleet as the War progressed and to replace them by boys trained in the Wireless School established by the Fleet at Scapa Flow. A point which war experience brought into considerable prominence was the difficulty of distinguishing, with sufficient rapidity, enemy vessels from our own ships both before, and, more particularly during, action. The difficulty applied to all classes of vessels, but was greatest in the case of torpedo craft and submarines. Steps were taken to deal with it, and satisfactory arrangements made for certain distinguishing marks visible at long distances to be worn during daylight by our own surface vessels. The question of identification at night was more difficult, and although we effected improvement in this respect also, the results were not so satisfactory. Of the original experimental work carried out by the Fleet at Scapa Flow none was more important than that connected with the safety of ships from mines. Early in the War it had become obvious that there was danger of a serious weakening of the Grand Fleet by successful mine attack, and no safeguard existed beyond the work of the mine-sweepers; these vessels could not work far afield, and in bad weather could not work even close to their bases, whereas the Fleet might be required to proceed to sea when mine-sweeping was impracticable. A solution of this difficulty was required. Commander Cecil V. Usborne, of the _Colossus_, in these circumstances proposed to me the trial of an apparatus which he suggested should be towed from the bows of ships; it was intended to fend off any mine encountered, provided the ship did not strike it absolutely “end on.” I ordered immediate trials; all the necessary _matériel_ was provided with Fleet labour and appliances, and starting with trials in a picket boat, they were continued until a series of experiments commenced in large ships, battleships and cruisers. I placed Rear-Admirals A. L. Duff and A. C. Leveson in charge of the experiments and great progress was made, although absolute success was not obtained.