On the 30th the 3rd Cruiser Squadron and 1st Light Cruiser Squadron, with destroyers, left Rosyth and carried out a sweep to the south-eastward, returning on the 31st. On the same day, a lamentable disaster occurred, the cruiser _Natal_ (Captain Eric Back) being blown up in Cromarty harbour with great loss of life. Captain Back was amongst those who lost their lives. It was reported by adjacent vessels at 3.25 P.M. that the ship was on fire, and at 3.30 P.M., before any action could be taken, the ship blew up and sank, the explosion taking place in her after magazines. Steps were taken to deal with the situation in case the explosion had been caused by an enemy submarine having entered the harbour, but it soon became evident that this was not the case. Examination of the wreck by divers later showed no signs of any external explosion. A court-martial was subsequently held at Chatham to investigate the causes of the disaster, but the conclusions were not made public. During the month of December independent exercises from the Fleet bases were continued, as well as target practice from Cromarty. As to the latter, an interesting practice was carried out by the _Iron Duke_ at the range, and under the conditions of battle practice before the War, in order to ascertain, by examining the actual hits made on the canvas of the target, whether the pre-War standard of shooting was being maintained. Some uncertainty existed owing to the great increase in the ranges at which practices were carried out during the War, namely, 16,000 to 19,000 yards, as compared with the 9,500 yards, which was the maximum peace range. The result was very satisfactory and indicated a most decided advance on pre-War accuracy of fire. On December 13th the first target practice was carried out in the Pentland Firth. This was in the nature of an experiment and, being successful, practice in this locality was later substituted for practice in the Moray Firth; it was far more convenient for the main Fleet base and much less extravagant in the use of screening and protecting destroyers. On December 16th Vice-Admiral Sir Martyn Jerram, K.C.B., relieved Vice-Admiral Sir George Warrender, Bart., in command of the 2nd Battle Squadron, on the termination of the latter officer’s three years’ command. During December patrols seaward of the bases were strengthened and considerably extended during the first and fourth quarters of the moon in order to frustrate any attempted mine-laying on the part of the enemy. This “dark night” patrol subsequently became a matter of routine. The 10th Cruiser Squadron’s weekly average showed: Ships intercepted, 35; sent in, 14; number of ships on patrol, 12; number at bases or _en route_, 7; number on special service, 2.