Owing to the danger of disclosing the position of the Fleet to enemy submarines or destroyers, it was not possible to use visual signalling at night, except with carefully shaded lamps which were only visible at a distance of about a quarter of a mile, and then only by the ship addressed, and this problem thus became complicated at night, in fogs or in very thick weather. Occasional resort had then to be made to wireless, but by signalling before dark all expected movements during the night, and by arranging the course of the Fleet so that few alterations were necessary, we succeeded in keeping almost absolute wireless silence. It had to be used, however, when important information from the Admiralty and elsewhere was to be transmitted to the Fleet-Flagship, or to senior officers of squadrons, or to single ships when at sea engaged in operations, etc., and early in the War we had to devise a method by which this could be done without calling up the ships in question by wireless, thus necessitating a reply from them, and thus possibly acquainting the enemy of their position. After a time a satisfactory and ingenious system of communicating the required information without causing the ship herself to divulge her position was devised by the Fleet Wireless officer, Lieutenant-Commander R. L. Nicholson. This plan worked excellently and gradually was greatly extended during the later stages of the War. It must not be thought that, because wireless signalling at sea was restricted, it was not intended to make full use of it when necessary and when silence was no longer required, such as when the fleets were within sight of one another. On the contrary, a great advance was made during the War in the use of wireless telegraphy for manœuvring the Battle Fleet, as well as in every other direction. So proficient did the ships become under the organisation introduced by Lieutenant-Commander Nicholson, assisted as he was by the very efficient wireless officers and wireless personnel, that in 1916 I could handle the Battle Fleet by wireless with as much ease and rapidity as by visual signals. At the beginning of the War ten minutes to a quarter of an hour would elapse before I could be sure that all ships had received a manœuvring wireless signal addressed to the whole Battle Fleet. In 1916 the time rarely exceeded two to three minutes. This great improvement was due to new methods introduced, as well as to incessant practice in harbour.